pubsub-mqtt.js

(function(f){if(typeof exports==="object"&&typeof module!=="undefined"){module.exports=f()}else if(typeof define==="function"&&define.amd){define([],f)}else{var g;if(typeof window!=="undefined"){g=window}else if(typeof global!=="undefined"){g=global}else if(typeof self!=="undefined"){g=self}else{g=this}g.MQTTAdapter = f()}})(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){

/**
 * This is the web browser implementation of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = require('./debug');
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;

/**
 * Use chrome.storage.local if we are in an app
 */

var storage;

if (typeof chrome !== 'undefined' && typeof chrome.storage !== 'undefined')
  storage = chrome.storage.local;
else
  storage = localstorage();

/**
 * Colors.
 */

exports.colors = [
  'lightseagreen',
  'forestgreen',
  'goldenrod',
  'dodgerblue',
  'darkorchid',
  'crimson'
];

/**
 * Currently only WebKit-based Web Inspectors, Firefox >= v31,
 * and the Firebug extension (any Firefox version) are known
 * to support "%c" CSS customizations.
 *
 * TODO: add a `localStorage` variable to explicitly enable/disable colors
 */

function useColors() {
  // is webkit? http://stackoverflow.com/a/16459606/376773
  return ('WebkitAppearance' in document.documentElement.style) ||
    // is firebug? http://stackoverflow.com/a/398120/376773
    (window.console && (console.firebug || (console.exception && console.table))) ||
    // is firefox >= v31?
    // https://developer.mozilla.org/en-US/docs/Tools/Web_Console#Styling_messages
    (navigator.userAgent.toLowerCase().match(/firefox\/(\d+)/) && parseInt(RegExp.$1, 10) >= 31);
}

/**
 * Map %j to `JSON.stringify()`, since no Web Inspectors do that by default.
 */

exports.formatters.j = function(v) {
  return JSON.stringify(v);
};


/**
 * Colorize log arguments if enabled.
 *
 * @api public
 */

function formatArgs() {
  var args = arguments;
  var useColors = this.useColors;

  args[0] = (useColors ? '%c' : '')
    + this.namespace
    + (useColors ? ' %c' : ' ')
    + args[0]
    + (useColors ? '%c ' : ' ')
    + '+' + exports.humanize(this.diff);

  if (!useColors) return args;

  var c = 'color: ' + this.color;
  args = [args[0], c, 'color: inherit'].concat(Array.prototype.slice.call(args, 1));

  // the final "%c" is somewhat tricky, because there could be other
  // arguments passed either before or after the %c, so we need to
  // figure out the correct index to insert the CSS into
  var index = 0;
  var lastC = 0;
  args[0].replace(/%[a-z%]/g, function(match) {
    if ('%%' === match) return;
    index++;
    if ('%c' === match) {
      // we only are interested in the *last* %c
      // (the user may have provided their own)
      lastC = index;
    }
  });

  args.splice(lastC, 0, c);
  return args;
}

/**
 * Invokes `console.log()` when available.
 * No-op when `console.log` is not a "function".
 *
 * @api public
 */

function log() {
  // this hackery is required for IE8/9, where
  // the `console.log` function doesn't have 'apply'
  return 'object' === typeof console
    && console.log
    && Function.prototype.apply.call(console.log, console, arguments);
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */

function save(namespaces) {
  try {
    if (null == namespaces) {
      storage.removeItem('debug');
    } else {
      storage.debug = namespaces;
    }
  } catch(e) {}
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */

function load() {
  var r;
  try {
    r = storage.debug;
  } catch(e) {}
  return r;
}

/**
 * Enable namespaces listed in `localStorage.debug` initially.
 */

exports.enable(load());

/**
 * Localstorage attempts to return the localstorage.
 *
 * This is necessary because safari throws
 * when a user disables cookies/localstorage
 * and you attempt to access it.
 *
 * @return {LocalStorage}
 * @api private
 */

function localstorage(){
  try {
    return window.localStorage;
  } catch (e) {}
}

},{"./debug":2}],2:[function(require,module,exports){

/**
 * This is the common logic for both the Node.js and web browser
 * implementations of `debug()`.
 *
 * Expose `debug()` as the module.
 */

exports = module.exports = debug;
exports.coerce = coerce;
exports.disable = disable;
exports.enable = enable;
exports.enabled = enabled;
exports.humanize = require('ms');

/**
 * The currently active debug mode names, and names to skip.
 */

exports.names = [];
exports.skips = [];

/**
 * Map of special "%n" handling functions, for the debug "format" argument.
 *
 * Valid key names are a single, lowercased letter, i.e. "n".
 */

exports.formatters = {};

/**
 * Previously assigned color.
 */

var prevColor = 0;

/**
 * Previous log timestamp.
 */

var prevTime;

/**
 * Select a color.
 *
 * @return {Number}
 * @api private
 */

function selectColor() {
  return exports.colors[prevColor++ % exports.colors.length];
}

/**
 * Create a debugger with the given `namespace`.
 *
 * @param {String} namespace
 * @return {Function}
 * @api public
 */

function debug(namespace) {

  // define the `disabled` version
  function disabled() {
  }
  disabled.enabled = false;

  // define the `enabled` version
  function enabled() {

    var self = enabled;

    // set `diff` timestamp
    var curr = +new Date();
    var ms = curr - (prevTime || curr);
    self.diff = ms;
    self.prev = prevTime;
    self.curr = curr;
    prevTime = curr;

    // add the `color` if not set
    if (null == self.useColors) self.useColors = exports.useColors();
    if (null == self.color && self.useColors) self.color = selectColor();

    var args = Array.prototype.slice.call(arguments);

    args[0] = exports.coerce(args[0]);

    if ('string' !== typeof args[0]) {
      // anything else let's inspect with %o
      args = ['%o'].concat(args);
    }

    // apply any `formatters` transformations
    var index = 0;
    args[0] = args[0].replace(/%([a-z%])/g, function(match, format) {
      // if we encounter an escaped % then don't increase the array index
      if (match === '%%') return match;
      index++;
      var formatter = exports.formatters[format];
      if ('function' === typeof formatter) {
        var val = args[index];
        match = formatter.call(self, val);

        // now we need to remove `args[index]` since it's inlined in the `format`
        args.splice(index, 1);
        index--;
      }
      return match;
    });

    if ('function' === typeof exports.formatArgs) {
      args = exports.formatArgs.apply(self, args);
    }
    var logFn = enabled.log || exports.log || console.log.bind(console);
    logFn.apply(self, args);
  }
  enabled.enabled = true;

  var fn = exports.enabled(namespace) ? enabled : disabled;

  fn.namespace = namespace;

  return fn;
}

/**
 * Enables a debug mode by namespaces. This can include modes
 * separated by a colon and wildcards.
 *
 * @param {String} namespaces
 * @api public
 */

function enable(namespaces) {
  exports.save(namespaces);

  var split = (namespaces || '').split(/[\s,]+/);
  var len = split.length;

  for (var i = 0; i < len; i++) {
    if (!split[i]) continue; // ignore empty strings
    namespaces = split[i].replace(/\*/g, '.*?');
    if (namespaces[0] === '-') {
      exports.skips.push(new RegExp('^' + namespaces.substr(1) + '$'));
    } else {
      exports.names.push(new RegExp('^' + namespaces + '$'));
    }
  }
}

/**
 * Disable debug output.
 *
 * @api public
 */

function disable() {
  exports.enable('');
}

/**
 * Returns true if the given mode name is enabled, false otherwise.
 *
 * @param {String} name
 * @return {Boolean}
 * @api public
 */

function enabled(name) {
  var i, len;
  for (i = 0, len = exports.skips.length; i < len; i++) {
    if (exports.skips[i].test(name)) {
      return false;
    }
  }
  for (i = 0, len = exports.names.length; i < len; i++) {
    if (exports.names[i].test(name)) {
      return true;
    }
  }
  return false;
}

/**
 * Coerce `val`.
 *
 * @param {Mixed} val
 * @return {Mixed}
 * @api private
 */

function coerce(val) {
  if (val instanceof Error) return val.stack || val.message;
  return val;
}

},{"ms":3}],3:[function(require,module,exports){
/**
 * Helpers.
 */

var s = 1000;
var m = s * 60;
var h = m * 60;
var d = h * 24;
var y = d * 365.25;

/**
 * Parse or format the given `val`.
 *
 * Options:
 *
 *  - `long` verbose formatting [false]
 *
 * @param {String|Number} val
 * @param {Object} options
 * @return {String|Number}
 * @api public
 */

module.exports = function(val, options){
  options = options || {};
  if ('string' == typeof val) return parse(val);
  return options.long
    ? long(val)
    : short(val);
};

/**
 * Parse the given `str` and return milliseconds.
 *
 * @param {String} str
 * @return {Number}
 * @api private
 */

function parse(str) {
  var match = /^((?:\d+)?\.?\d+) *(milliseconds?|msecs?|ms|seconds?|secs?|s|minutes?|mins?|m|hours?|hrs?|h|days?|d|years?|yrs?|y)?$/i.exec(str);
  if (!match) return;
  var n = parseFloat(match[1]);
  var type = (match[2] || 'ms').toLowerCase();
  switch (type) {
    case 'years':
    case 'year':
    case 'yrs':
    case 'yr':
    case 'y':
      return n * y;
    case 'days':
    case 'day':
    case 'd':
      return n * d;
    case 'hours':
    case 'hour':
    case 'hrs':
    case 'hr':
    case 'h':
      return n * h;
    case 'minutes':
    case 'minute':
    case 'mins':
    case 'min':
    case 'm':
      return n * m;
    case 'seconds':
    case 'second':
    case 'secs':
    case 'sec':
    case 's':
      return n * s;
    case 'milliseconds':
    case 'millisecond':
    case 'msecs':
    case 'msec':
    case 'ms':
      return n;
  }
}

/**
 * Short format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function short(ms) {
  if (ms >= d) return Math.round(ms / d) + 'd';
  if (ms >= h) return Math.round(ms / h) + 'h';
  if (ms >= m) return Math.round(ms / m) + 'm';
  if (ms >= s) return Math.round(ms / s) + 's';
  return ms + 'ms';
}

/**
 * Long format for `ms`.
 *
 * @param {Number} ms
 * @return {String}
 * @api private
 */

function long(ms) {
  return plural(ms, d, 'day')
    || plural(ms, h, 'hour')
    || plural(ms, m, 'minute')
    || plural(ms, s, 'second')
    || ms + ' ms';
}

/**
 * Pluralization helper.
 */

function plural(ms, n, name) {
  if (ms < n) return;
  if (ms < n * 1.5) return Math.floor(ms / n) + ' ' + name;
  return Math.ceil(ms / n) + ' ' + name + 's';
}

},{}],4:[function(require,module,exports){
(function (global){
/**
 * @license
 * lodash 3.7.0 (Custom Build) <https://lodash.com/>
 * Build: `lodash modern -d -o ./index.js`
 * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2015 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <https://lodash.com/license>
 */
;(function() {

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  typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
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  /*--------------------------------------------------------------------------*/

  /**
   * The base implementation of `compareAscending` which compares values and
   * sorts them in ascending order without guaranteeing a stable sort.
   *
   * @private
   * @param {*} value The value to compare to `other`.
   * @param {*} other The value to compare to `value`.
   * @returns {number} Returns the sort order indicator for `value`.
   */
  function baseCompareAscending(value, other) {
    if (value !== other) {
      var valIsReflexive = value === value,
          othIsReflexive = other === other;

      if (value > other || !valIsReflexive || (value === undefined && othIsReflexive)) {
        return 1;
      }
      if (value < other || !othIsReflexive || (other === undefined && valIsReflexive)) {
        return -1;
      }
    }
    return 0;
  }

  /**
   * The base implementation of `_.findIndex` and `_.findLastIndex` without
   * support for callback shorthands and `this` binding.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {Function} predicate The function invoked per iteration.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseFindIndex(array, predicate, fromRight) {
    var length = array.length,
        index = fromRight ? length : -1;

    while ((fromRight ? index-- : ++index < length)) {
      if (predicate(array[index], index, array)) {
        return index;
      }
    }
    return -1;
  }

  /**
   * The base implementation of `_.indexOf` without support for binary searches.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {*} value The value to search for.
   * @param {number} fromIndex The index to search from.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseIndexOf(array, value, fromIndex) {
    if (value !== value) {
      return indexOfNaN(array, fromIndex);
    }
    var index = fromIndex - 1,
        length = array.length;

    while (++index < length) {
      if (array[index] === value) {
        return index;
      }
    }
    return -1;
  }

  /**
   * The base implementation of `_.isFunction` without support for environments
   * with incorrect `typeof` results.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
   */
  function baseIsFunction(value) {
    // Avoid a Chakra JIT bug in compatibility modes of IE 11.
    // See https://github.com/jashkenas/underscore/issues/1621 for more details.
    return typeof value == 'function' || false;
  }

  /**
   * Converts `value` to a string if it is not one. An empty string is returned
   * for `null` or `undefined` values.
   *
   * @private
   * @param {*} value The value to process.
   * @returns {string} Returns the string.
   */
  function baseToString(value) {
    if (typeof value == 'string') {
      return value;
    }
    return value == null ? '' : (value + '');
  }

  /**
   * Used by `_.max` and `_.min` as the default callback for string values.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the code unit of the first character of the string.
   */
  function charAtCallback(string) {
    return string.charCodeAt(0);
  }

  /**
   * Used by `_.trim` and `_.trimLeft` to get the index of the first character
   * of `string` that is not found in `chars`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @param {string} chars The characters to find.
   * @returns {number} Returns the index of the first character not found in `chars`.
   */
  function charsLeftIndex(string, chars) {
    var index = -1,
        length = string.length;

    while (++index < length && chars.indexOf(string.charAt(index)) > -1) {}
    return index;
  }

  /**
   * Used by `_.trim` and `_.trimRight` to get the index of the last character
   * of `string` that is not found in `chars`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @param {string} chars The characters to find.
   * @returns {number} Returns the index of the last character not found in `chars`.
   */
  function charsRightIndex(string, chars) {
    var index = string.length;

    while (index-- && chars.indexOf(string.charAt(index)) > -1) {}
    return index;
  }

  /**
   * Used by `_.sortBy` to compare transformed elements of a collection and stable
   * sort them in ascending order.
   *
   * @private
   * @param {Object} object The object to compare to `other`.
   * @param {Object} other The object to compare to `object`.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareAscending(object, other) {
    return baseCompareAscending(object.criteria, other.criteria) || (object.index - other.index);
  }

  /**
   * Used by `_.sortByOrder` to compare multiple properties of each element
   * in a collection and stable sort them in the following order:
   *
   * If `orders` is unspecified, sort in ascending order for all properties.
   * Otherwise, for each property, sort in ascending order if its corresponding value in
   * orders is true, and descending order if false.
   *
   * @private
   * @param {Object} object The object to compare to `other`.
   * @param {Object} other The object to compare to `object`.
   * @param {boolean[]} orders The order to sort by for each property.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareMultiple(object, other, orders) {
    var index = -1,
        objCriteria = object.criteria,
        othCriteria = other.criteria,
        length = objCriteria.length,
        ordersLength = orders.length;

    while (++index < length) {
      var result = baseCompareAscending(objCriteria[index], othCriteria[index]);
      if (result) {
        if (index >= ordersLength) {
          return result;
        }
        return result * (orders[index] ? 1 : -1);
      }
    }
    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
    // that causes it, under certain circumstances, to provide the same value for
    // `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
    // for more details.
    //
    // This also ensures a stable sort in V8 and other engines.
    // See https://code.google.com/p/v8/issues/detail?id=90 for more details.
    return object.index - other.index;
  }

  /**
   * Used by `_.deburr` to convert latin-1 supplementary letters to basic latin letters.
   *
   * @private
   * @param {string} letter The matched letter to deburr.
   * @returns {string} Returns the deburred letter.
   */
  function deburrLetter(letter) {
    return deburredLetters[letter];
  }

  /**
   * Used by `_.escape` to convert characters to HTML entities.
   *
   * @private
   * @param {string} chr The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeHtmlChar(chr) {
    return htmlEscapes[chr];
  }

  /**
   * Used by `_.template` to escape characters for inclusion in compiled
   * string literals.
   *
   * @private
   * @param {string} chr The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeStringChar(chr) {
    return '\\' + stringEscapes[chr];
  }

  /**
   * Gets the index at which the first occurrence of `NaN` is found in `array`.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {number} fromIndex The index to search from.
   * @param {boolean} [fromRight] Specify iterating from right to left.
   * @returns {number} Returns the index of the matched `NaN`, else `-1`.
   */
  function indexOfNaN(array, fromIndex, fromRight) {
    var length = array.length,
        index = fromIndex + (fromRight ? 0 : -1);

    while ((fromRight ? index-- : ++index < length)) {
      var other = array[index];
      if (other !== other) {
        return index;
      }
    }
    return -1;
  }

  /**
   * Checks if `value` is object-like.
   *
   * @private
   * @param {*} value The value to check.
   * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
   */
  function isObjectLike(value) {
    return !!value && typeof value == 'object';
  }

  /**
   * Used by `trimmedLeftIndex` and `trimmedRightIndex` to determine if a
   * character code is whitespace.
   *
   * @private
   * @param {number} charCode The character code to inspect.
   * @returns {boolean} Returns `true` if `charCode` is whitespace, else `false`.
   */
  function isSpace(charCode) {
    return ((charCode <= 160 && (charCode >= 9 && charCode <= 13) || charCode == 32 || charCode == 160) || charCode == 5760 || charCode == 6158 ||
      (charCode >= 8192 && (charCode <= 8202 || charCode == 8232 || charCode == 8233 || charCode == 8239 || charCode == 8287 || charCode == 12288 || charCode == 65279)));
  }

  /**
   * Replaces all `placeholder` elements in `array` with an internal placeholder
   * and returns an array of their indexes.
   *
   * @private
   * @param {Array} array The array to modify.
   * @param {*} placeholder The placeholder to replace.
   * @returns {Array} Returns the new array of placeholder indexes.
   */
  function replaceHolders(array, placeholder) {
    var index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      if (array[index] === placeholder) {
        array[index] = PLACEHOLDER;
        result[++resIndex] = index;
      }
    }
    return result;
  }

  /**
   * An implementation of `_.uniq` optimized for sorted arrays without support
   * for callback shorthands and `this` binding.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {Function} [iteratee] The function invoked per iteration.
   * @returns {Array} Returns the new duplicate-value-free array.
   */
  function sortedUniq(array, iteratee) {
    var seen,
        index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      var value = array[index],
          computed = iteratee ? iteratee(value, index, array) : value;

      if (!index || seen !== computed) {
        seen = computed;
        result[++resIndex] = value;
      }
    }
    return result;
  }

  /**
   * Used by `_.trim` and `_.trimLeft` to get the index of the first non-whitespace
   * character of `string`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the index of the first non-whitespace character.
   */
  function trimmedLeftIndex(string) {
    var index = -1,
        length = string.length;

    while (++index < length && isSpace(string.charCodeAt(index))) {}
    return index;
  }

  /**
   * Used by `_.trim` and `_.trimRight` to get the index of the last non-whitespace
   * character of `string`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the index of the last non-whitespace character.
   */
  function trimmedRightIndex(string) {
    var index = string.length;

    while (index-- && isSpace(string.charCodeAt(index))) {}
    return index;
  }

  /**
   * Used by `_.unescape` to convert HTML entities to characters.
   *
   * @private
   * @param {string} chr The matched character to unescape.
   * @returns {string} Returns the unescaped character.
   */
  function unescapeHtmlChar(chr) {
    return htmlUnescapes[chr];
  }

  /*--------------------------------------------------------------------------*/

  /**
   * Create a new pristine `lodash` function using the given `context` object.
   *
   * @static
   * @memberOf _
   * @category Utility
   * @param {Object} [context=root] The context object.
   * @returns {Function} Returns a new `lodash` function.
   * @example
   *
   * _.mixin({ 'foo': _.constant('foo') });
   *
   * var lodash = _.runInContext();
   * lodash.mixin({ 'bar': lodash.constant('bar') });
   *
   * _.isFunction(_.foo);
   * // => true
   * _.isFunction(_.bar);
   * // => false
   *
   * lodash.isFunction(lodash.foo);
   * // => false
   * lodash.isFunction(lodash.bar);
   * // => true
   *
   * // using `context` to mock `Date#getTime` use in `_.now`
   * var mock = _.runInContext({
   *   'Date': function() {
   *     return { 'getTime': getTimeMock };
   *   }
   * });
   *
   * // or creating a suped-up `defer` in Node.js
   * var defer = _.runInContext({ 'setTimeout': setImmediate }).defer;
   */
  function runInContext(context) {
    // Avoid issues with some ES3 environments that attempt to use values, named
    // after built-in constructors like `Object`, for the creation of literals.
    // ES5 clears this up by stating that literals must use built-in constructors.
    // See https://es5.github.io/#x11.1.5 for more details.
    context = context ? _.defaults(root.Object(), context, _.pick(root, contextProps)) : root;

    /** Native constructor references. */
    var Array = context.Array,
        Date = context.Date,
        Error = context.Error,
        Function = context.Function,
        Math = context.Math,
        Number = context.Number,
        Object = context.Object,
        RegExp = context.RegExp,
        String = context.String,
        TypeError = context.TypeError;

    /** Used for native method references. */
    var arrayProto = Array.prototype,
        objectProto = Object.prototype,
        stringProto = String.prototype;

    /** Used to detect DOM support. */
    var document = (document = context.window) && document.document;

    /** Used to resolve the decompiled source of functions. */
    var fnToString = Function.prototype.toString;

    /** Used to check objects for own properties. */
    var hasOwnProperty = objectProto.hasOwnProperty;

    /** Used to generate unique IDs. */
    var idCounter = 0;

    /**
     * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
     * of values.
     */
    var objToString = objectProto.toString;

    /** Used to restore the original `_` reference in `_.noConflict`. */
    var oldDash = context._;

    /** Used to detect if a method is native. */
    var reIsNative = RegExp('^' +
      escapeRegExp(objToString)
      .replace(/toString|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
    );

    /** Native method references. */
    var ArrayBuffer = isNative(ArrayBuffer = context.ArrayBuffer) && ArrayBuffer,
        bufferSlice = isNative(bufferSlice = ArrayBuffer && new ArrayBuffer(0).slice) && bufferSlice,
        ceil = Math.ceil,
        clearTimeout = context.clearTimeout,
        floor = Math.floor,
        getOwnPropertySymbols = isNative(getOwnPropertySymbols = Object.getOwnPropertySymbols) && getOwnPropertySymbols,
        getPrototypeOf = isNative(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
        push = arrayProto.push,
        preventExtensions = isNative(Object.preventExtensions = Object.preventExtensions) && preventExtensions,
        propertyIsEnumerable = objectProto.propertyIsEnumerable,
        Set = isNative(Set = context.Set) && Set,
        setTimeout = context.setTimeout,
        splice = arrayProto.splice,
        Uint8Array = isNative(Uint8Array = context.Uint8Array) && Uint8Array,
        WeakMap = isNative(WeakMap = context.WeakMap) && WeakMap;

    /** Used to clone array buffers. */
    var Float64Array = (function() {
      // Safari 5 errors when using an array buffer to initialize a typed array
      // where the array buffer's `byteLength` is not a multiple of the typed
      // array's `BYTES_PER_ELEMENT`.
      try {
        var func = isNative(func = context.Float64Array) && func,
            result = new func(new ArrayBuffer(10), 0, 1) && func;
      } catch(e) {}
      return result;
    }());

    /** Used as `baseAssign`. */
    var nativeAssign = (function() {
      // Avoid `Object.assign` in Firefox 34-37 which have an early implementation
      // with a now defunct try/catch behavior. See https://bugzilla.mozilla.org/show_bug.cgi?id=1103344
      // for more details.
      //
      // Use `Object.preventExtensions` on a plain object instead of simply using
      // `Object('x')` because Chrome and IE fail to throw an error when attempting
      // to assign values to readonly indexes of strings in strict mode.
      var object = { '1': 0 },
          func = preventExtensions && isNative(func = Object.assign) && func;

      try { func(preventExtensions(object), 'xo'); } catch(e) {}
      return !object[1] && func;
    }());

    /* Native method references for those with the same name as other `lodash` methods. */
    var nativeIsArray = isNative(nativeIsArray = Array.isArray) && nativeIsArray,
        nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate,
        nativeIsFinite = context.isFinite,
        nativeKeys = isNative(nativeKeys = Object.keys) && nativeKeys,
        nativeMax = Math.max,
        nativeMin = Math.min,
        nativeNow = isNative(nativeNow = Date.now) && nativeNow,
        nativeNumIsFinite = isNative(nativeNumIsFinite = Number.isFinite) && nativeNumIsFinite,
        nativeParseInt = context.parseInt,
        nativeRandom = Math.random;

    /** Used as references for `-Infinity` and `Infinity`. */
    var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
        POSITIVE_INFINITY = Number.POSITIVE_INFINITY;

    /** Used as references for the maximum length and index of an array. */
    var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1,
        MAX_ARRAY_INDEX =  MAX_ARRAY_LENGTH - 1,
        HALF_MAX_ARRAY_LENGTH = MAX_ARRAY_LENGTH >>> 1;

    /** Used as the size, in bytes, of each `Float64Array` element. */
    var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT : 0;

    /**
     * Used as the [maximum length](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.max_safe_integer)
     * of an array-like value.
     */
    var MAX_SAFE_INTEGER = Math.pow(2, 53) - 1;

    /** Used to store function metadata. */
    var metaMap = WeakMap && new WeakMap;

    /** Used to lookup unminified function names. */
    var realNames = {};

    /*------------------------------------------------------------------------*/

    /**
     * Creates a `lodash` object which wraps `value` to enable implicit chaining.
     * Methods that operate on and return arrays, collections, and functions can
     * be chained together. Methods that return a boolean or single value will
     * automatically end the chain returning the unwrapped value. Explicit chaining
     * may be enabled using `_.chain`. The execution of chained methods is lazy,
     * that is, execution is deferred until `_#value` is implicitly or explicitly
     * called.
     *
     * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
     * fusion is an optimization that merges iteratees to avoid creating intermediate
     * arrays and reduce the number of iteratee executions.
     *
     * Chaining is supported in custom builds as long as the `_#value` method is
     * directly or indirectly included in the build.
     *
     * In addition to lodash methods, wrappers have `Array` and `String` methods.
     *
     * The wrapper `Array` methods are:
     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`,
     * `splice`, and `unshift`
     *
     * The wrapper `String` methods are:
     * `replace` and `split`
     *
     * The wrapper methods that support shortcut fusion are:
     * `compact`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `filter`,
     * `first`, `initial`, `last`, `map`, `pluck`, `reject`, `rest`, `reverse`,
     * `slice`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `toArray`,
     * and `where`
     *
     * The chainable wrapper methods are:
     * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
     * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
     * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defer`, `delay`,
     * `difference`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `fill`,
     * `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`, `forEach`,
     * `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `functions`,
     * `groupBy`, `indexBy`, `initial`, `intersection`, `invert`, `invoke`, `keys`,
     * `keysIn`, `map`, `mapValues`, `matches`, `matchesProperty`, `memoize`,
     * `merge`, `mixin`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
     * `partition`, `pick`, `plant`, `pluck`, `property`, `propertyOf`, `pull`,
     * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `reverse`,
     * `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`, `sortByOrder`, `splice`,
     * `spread`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `tap`,
     * `throttle`, `thru`, `times`, `toArray`, `toPlainObject`, `transform`,
     * `union`, `uniq`, `unshift`, `unzip`, `values`, `valuesIn`, `where`,
     * `without`, `wrap`, `xor`, `zip`, and `zipObject`
     *
     * The wrapper methods that are **not** chainable by default are:
     * `add`, `attempt`, `camelCase`, `capitalize`, `clone`, `cloneDeep`, `deburr`,
     * `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`,
     * `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`, `has`,
     * `identity`, `includes`, `indexOf`, `inRange`, `isArguments`, `isArray`,
     * `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`, `isFinite`
     * `isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`,
     * `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `isTypedArray`,
     * `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`, `noConflict`,
     * `noop`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`,
     * `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`, `shift`, `size`,
     * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`, `startsWith`,
     * `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`, `unescape`,
     * `uniqueId`, `value`, and `words`
     *
     * The wrapper method `sample` will return a wrapped value when `n` is provided,
     * otherwise an unwrapped value is returned.
     *
     * @name _
     * @constructor
     * @category Chain
     * @param {*} value The value to wrap in a `lodash` instance.
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var wrapped = _([1, 2, 3]);
     *
     * // returns an unwrapped value
     * wrapped.reduce(function(total, n) {
     *   return total + n;
     * });
     * // => 6
     *
     * // returns a wrapped value
     * var squares = wrapped.map(function(n) {
     *   return n * n;
     * });
     *
     * _.isArray(squares);
     * // => false
     *
     * _.isArray(squares.value());
     * // => true
     */
    function lodash(value) {
      if (isObjectLike(value) && !isArray(value) && !(value instanceof LazyWrapper)) {
        if (value instanceof LodashWrapper) {
          return value;
        }
        if (hasOwnProperty.call(value, '__chain__') && hasOwnProperty.call(value, '__wrapped__')) {
          return wrapperClone(value);
        }
      }
      return new LodashWrapper(value);
    }

    /**
     * The function whose prototype all chaining wrappers inherit from.
     *
     * @private
     */
    function baseLodash() {
      // No operation performed.
    }

    /**
     * The base constructor for creating `lodash` wrapper objects.
     *
     * @private
     * @param {*} value The value to wrap.
     * @param {boolean} [chainAll] Enable chaining for all wrapper methods.
     * @param {Array} [actions=[]] Actions to peform to resolve the unwrapped value.
     */
    function LodashWrapper(value, chainAll, actions) {
      this.__wrapped__ = value;
      this.__actions__ = actions || [];
      this.__chain__ = !!chainAll;
    }

    /**
     * An object environment feature flags.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    var support = lodash.support = {};

    (function(x) {
      var Ctor = function() { this.x = x; },
          object = { '0': x, 'length': x },
          props = [];

      Ctor.prototype = { 'valueOf': x, 'y': x };
      for (var key in new Ctor) { props.push(key); }

      /**
       * Detect if functions can be decompiled by `Function#toString`
       * (all but Firefox OS certified apps, older Opera mobile browsers, and
       * the PlayStation 3; forced `false` for Windows 8 apps).
       *
       * @memberOf _.support
       * @type boolean
       */
      support.funcDecomp = /\bthis\b/.test(function() { return this; });

      /**
       * Detect if `Function#name` is supported (all but IE).
       *
       * @memberOf _.support
       * @type boolean
       */
      support.funcNames = typeof Function.name == 'string';

      /**
       * Detect if the DOM is supported.
       *
       * @memberOf _.support
       * @type boolean
       */
      try {
        support.dom = document.createDocumentFragment().nodeType === 11;
      } catch(e) {
        support.dom = false;
      }

      /**
       * Detect if `arguments` object indexes are non-enumerable.
       *
       * In Firefox < 4, IE < 9, PhantomJS, and Safari < 5.1 `arguments` object
       * indexes are non-enumerable. Chrome < 25 and Node.js < 0.11.0 treat
       * `arguments` object indexes as non-enumerable and fail `hasOwnProperty`
       * checks for indexes that exceed the number of function parameters and
       * whose associated argument values are `0`.
       *
       * @memberOf _.support
       * @type boolean
       */
      try {
        support.nonEnumArgs = !propertyIsEnumerable.call(arguments, 1);
      } catch(e) {
        support.nonEnumArgs = true;
      }
    }(1, 0));

    /**
     * By default, the template delimiters used by lodash are like those in
     * embedded Ruby (ERB). Change the following template settings to use
     * alternative delimiters.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    lodash.templateSettings = {

      /**
       * Used to detect `data` property values to be HTML-escaped.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'escape': reEscape,

      /**
       * Used to detect code to be evaluated.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'evaluate': reEvaluate,

      /**
       * Used to detect `data` property values to inject.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'interpolate': reInterpolate,

      /**
       * Used to reference the data object in the template text.
       *
       * @memberOf _.templateSettings
       * @type string
       */
      'variable': '',

      /**
       * Used to import variables into the compiled template.
       *
       * @memberOf _.templateSettings
       * @type Object
       */
      'imports': {

        /**
         * A reference to the `lodash` function.
         *
         * @memberOf _.templateSettings.imports
         * @type Function
         */
        '_': lodash
      }
    };

    /*------------------------------------------------------------------------*/

    /**
     * Creates a lazy wrapper object which wraps `value` to enable lazy evaluation.
     *
     * @private
     * @param {*} value The value to wrap.
     */
    function LazyWrapper(value) {
      this.__wrapped__ = value;
      this.__actions__ = null;
      this.__dir__ = 1;
      this.__dropCount__ = 0;
      this.__filtered__ = false;
      this.__iteratees__ = null;
      this.__takeCount__ = POSITIVE_INFINITY;
      this.__views__ = null;
    }

    /**
     * Creates a clone of the lazy wrapper object.
     *
     * @private
     * @name clone
     * @memberOf LazyWrapper
     * @returns {Object} Returns the cloned `LazyWrapper` object.
     */
    function lazyClone() {
      var actions = this.__actions__,
          iteratees = this.__iteratees__,
          views = this.__views__,
          result = new LazyWrapper(this.__wrapped__);

      result.__actions__ = actions ? arrayCopy(actions) : null;
      result.__dir__ = this.__dir__;
      result.__filtered__ = this.__filtered__;
      result.__iteratees__ = iteratees ? arrayCopy(iteratees) : null;
      result.__takeCount__ = this.__takeCount__;
      result.__views__ = views ? arrayCopy(views) : null;
      return result;
    }

    /**
     * Reverses the direction of lazy iteration.
     *
     * @private
     * @name reverse
     * @memberOf LazyWrapper
     * @returns {Object} Returns the new reversed `LazyWrapper` object.
     */
    function lazyReverse() {
      if (this.__filtered__) {
        var result = new LazyWrapper(this);
        result.__dir__ = -1;
        result.__filtered__ = true;
      } else {
        result = this.clone();
        result.__dir__ *= -1;
      }
      return result;
    }

    /**
     * Extracts the unwrapped value from its lazy wrapper.
     *
     * @private
     * @name value
     * @memberOf LazyWrapper
     * @returns {*} Returns the unwrapped value.
     */
    function lazyValue() {
      var array = this.__wrapped__.value();
      if (!isArray(array)) {
        return baseWrapperValue(array, this.__actions__);
      }
      var dir = this.__dir__,
          isRight = dir < 0,
          view = getView(0, array.length, this.__views__),
          start = view.start,
          end = view.end,
          length = end - start,
          index = isRight ? end : (start - 1),
          takeCount = nativeMin(length, this.__takeCount__),
          iteratees = this.__iteratees__,
          iterLength = iteratees ? iteratees.length : 0,
          resIndex = 0,
          result = [];

      outer:
      while (length-- && resIndex < takeCount) {
        index += dir;

        var iterIndex = -1,
            value = array[index];

        while (++iterIndex < iterLength) {
          var data = iteratees[iterIndex],
              iteratee = data.iteratee,
              type = data.type;

          if (type == LAZY_DROP_WHILE_FLAG) {
            if (data.done && (isRight ? (index > data.index) : (index < data.index))) {
              data.count = 0;
              data.done = false;
            }
            data.index = index;
            if (!data.done) {
              var limit = data.limit;
              if (!(data.done = limit > -1 ? (data.count++ >= limit) : !iteratee(value))) {
                continue outer;
              }
            }
          } else {
            var computed = iteratee(value);
            if (type == LAZY_MAP_FLAG) {
              value = computed;
            } else if (!computed) {
              if (type == LAZY_FILTER_FLAG) {
                continue outer;
              } else {
                break outer;
              }
            }
          }
        }
        result[resIndex++] = value;
      }
      return result;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a cache object to store key/value pairs.
     *
     * @private
     * @static
     * @name Cache
     * @memberOf _.memoize
     */
    function MapCache() {
      this.__data__ = {};
    }

    /**
     * Removes `key` and its value from the cache.
     *
     * @private
     * @name delete
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the value to remove.
     * @returns {boolean} Returns `true` if the entry was removed successfully, else `false`.
     */
    function mapDelete(key) {
      return this.has(key) && delete this.__data__[key];
    }

    /**
     * Gets the cached value for `key`.
     *
     * @private
     * @name get
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the value to get.
     * @returns {*} Returns the cached value.
     */
    function mapGet(key) {
      return key == '__proto__' ? undefined : this.__data__[key];
    }

    /**
     * Checks if a cached value for `key` exists.
     *
     * @private
     * @name has
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the entry to check.
     * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
     */
    function mapHas(key) {
      return key != '__proto__' && hasOwnProperty.call(this.__data__, key);
    }

    /**
     * Sets `value` to `key` of the cache.
     *
     * @private
     * @name set
     * @memberOf _.memoize.Cache
     * @param {string} key The key of the value to cache.
     * @param {*} value The value to cache.
     * @returns {Object} Returns the cache object.
     */
    function mapSet(key, value) {
      if (key != '__proto__') {
        this.__data__[key] = value;
      }
      return this;
    }

    /*------------------------------------------------------------------------*/

    /**
     *
     * Creates a cache object to store unique values.
     *
     * @private
     * @param {Array} [values] The values to cache.
     */
    function SetCache(values) {
      var length = values ? values.length : 0;

      this.data = { 'hash': nativeCreate(null), 'set': new Set };
      while (length--) {
        this.push(values[length]);
      }
    }

    /**
     * Checks if `value` is in `cache` mimicking the return signature of
     * `_.indexOf` by returning `0` if the value is found, else `-1`.
     *
     * @private
     * @param {Object} cache The cache to search.
     * @param {*} value The value to search for.
     * @returns {number} Returns `0` if `value` is found, else `-1`.
     */
    function cacheIndexOf(cache, value) {
      var data = cache.data,
          result = (typeof value == 'string' || isObject(value)) ? data.set.has(value) : data.hash[value];

      return result ? 0 : -1;
    }

    /**
     * Adds `value` to the cache.
     *
     * @private
     * @name push
     * @memberOf SetCache
     * @param {*} value The value to cache.
     */
    function cachePush(value) {
      var data = this.data;
      if (typeof value == 'string' || isObject(value)) {
        data.set.add(value);
      } else {
        data.hash[value] = true;
      }
    }

    /*------------------------------------------------------------------------*/

    /**
     * Copies the values of `source` to `array`.
     *
     * @private
     * @param {Array} source The array to copy values from.
     * @param {Array} [array=[]] The array to copy values to.
     * @returns {Array} Returns `array`.
     */
    function arrayCopy(source, array) {
      var index = -1,
          length = source.length;

      array || (array = Array(length));
      while (++index < length) {
        array[index] = source[index];
      }
      return array;
    }

    /**
     * A specialized version of `_.forEach` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns `array`.
     */
    function arrayEach(array, iteratee) {
      var index = -1,
          length = array.length;

      while (++index < length) {
        if (iteratee(array[index], index, array) === false) {
          break;
        }
      }
      return array;
    }

    /**
     * A specialized version of `_.forEachRight` for arrays without support for
     * callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns `array`.
     */
    function arrayEachRight(array, iteratee) {
      var length = array.length;

      while (length--) {
        if (iteratee(array[length], length, array) === false) {
          break;
        }
      }
      return array;
    }

    /**
     * A specialized version of `_.every` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`.
     */
    function arrayEvery(array, predicate) {
      var index = -1,
          length = array.length;

      while (++index < length) {
        if (!predicate(array[index], index, array)) {
          return false;
        }
      }
      return true;
    }

    /**
     * A specialized version of `_.filter` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Array} Returns the new filtered array.
     */
    function arrayFilter(array, predicate) {
      var index = -1,
          length = array.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];
        if (predicate(value, index, array)) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.map` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns the new mapped array.
     */
    function arrayMap(array, iteratee) {
      var index = -1,
          length = array.length,
          result = Array(length);

      while (++index < length) {
        result[index] = iteratee(array[index], index, array);
      }
      return result;
    }

    /**
     * A specialized version of `_.max` for arrays without support for iteratees.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @returns {*} Returns the maximum value.
     */
    function arrayMax(array) {
      var index = -1,
          length = array.length,
          result = NEGATIVE_INFINITY;

      while (++index < length) {
        var value = array[index];
        if (value > result) {
          result = value;
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.min` for arrays without support for iteratees.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @returns {*} Returns the minimum value.
     */
    function arrayMin(array) {
      var index = -1,
          length = array.length,
          result = POSITIVE_INFINITY;

      while (++index < length) {
        var value = array[index];
        if (value < result) {
          result = value;
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.reduce` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {boolean} [initFromArray] Specify using the first element of `array`
     *  as the initial value.
     * @returns {*} Returns the accumulated value.
     */
    function arrayReduce(array, iteratee, accumulator, initFromArray) {
      var index = -1,
          length = array.length;

      if (initFromArray && length) {
        accumulator = array[++index];
      }
      while (++index < length) {
        accumulator = iteratee(accumulator, array[index], index, array);
      }
      return accumulator;
    }

    /**
     * A specialized version of `_.reduceRight` for arrays without support for
     * callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {boolean} [initFromArray] Specify using the last element of `array`
     *  as the initial value.
     * @returns {*} Returns the accumulated value.
     */
    function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
      var length = array.length;
      if (initFromArray && length) {
        accumulator = array[--length];
      }
      while (length--) {
        accumulator = iteratee(accumulator, array[length], length, array);
      }
      return accumulator;
    }

    /**
     * A specialized version of `_.some` for arrays without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     */
    function arraySome(array, predicate) {
      var index = -1,
          length = array.length;

      while (++index < length) {
        if (predicate(array[index], index, array)) {
          return true;
        }
      }
      return false;
    }

    /**
     * A specialized version of `_.sum` for arrays without support for iteratees.
     *
     * @private
     * @param {Array} array The array to iterate over.
     * @returns {number} Returns the sum.
     */
    function arraySum(array) {
      var length = array.length,
          result = 0;

      while (length--) {
        result += +array[length] || 0;
      }
      return result;
    }

    /**
     * Used by `_.defaults` to customize its `_.assign` use.
     *
     * @private
     * @param {*} objectValue The destination object property value.
     * @param {*} sourceValue The source object property value.
     * @returns {*} Returns the value to assign to the destination object.
     */
    function assignDefaults(objectValue, sourceValue) {
      return objectValue === undefined ? sourceValue : objectValue;
    }

    /**
     * Used by `_.template` to customize its `_.assign` use.
     *
     * **Note:** This function is like `assignDefaults` except that it ignores
     * inherited property values when checking if a property is `undefined`.
     *
     * @private
     * @param {*} objectValue The destination object property value.
     * @param {*} sourceValue The source object property value.
     * @param {string} key The key associated with the object and source values.
     * @param {Object} object The destination object.
     * @returns {*} Returns the value to assign to the destination object.
     */
    function assignOwnDefaults(objectValue, sourceValue, key, object) {
      return (objectValue === undefined || !hasOwnProperty.call(object, key))
        ? sourceValue
        : objectValue;
    }

    /**
     * A specialized version of `_.assign` for customizing assigned values without
     * support for argument juggling, multiple sources, and `this` binding `customizer`
     * functions.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {Function} customizer The function to customize assigned values.
     * @returns {Object} Returns `object`.
     */
    function assignWith(object, source, customizer) {
      var props = keys(source);
      push.apply(props, getSymbols(source));

      var index = -1,
          length = props.length;

      while (++index < length) {
        var key = props[index],
            value = object[key],
            result = customizer(value, source[key], key, object, source);

        if ((result === result ? (result !== value) : (value === value)) ||
            (value === undefined && !(key in object))) {
          object[key] = result;
        }
      }
      return object;
    }

    /**
     * The base implementation of `_.assign` without support for argument juggling,
     * multiple sources, and `customizer` functions.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @returns {Object} Returns `object`.
     */
    var baseAssign = nativeAssign || function(object, source) {
      return source == null
        ? object
        : baseCopy(source, getSymbols(source), baseCopy(source, keys(source), object));
    };

    /**
     * The base implementation of `_.at` without support for string collections
     * and individual key arguments.
     *
     * @private
     * @param {Array|Object} collection The collection to iterate over.
     * @param {number[]|string[]} props The property names or indexes of elements to pick.
     * @returns {Array} Returns the new array of picked elements.
     */
    function baseAt(collection, props) {
      var index = -1,
          length = collection.length,
          isArr = isLength(length),
          propsLength = props.length,
          result = Array(propsLength);

      while(++index < propsLength) {
        var key = props[index];
        if (isArr) {
          result[index] = isIndex(key, length) ? collection[key] : undefined;
        } else {
          result[index] = collection[key];
        }
      }
      return result;
    }

    /**
     * Copies properties of `source` to `object`.
     *
     * @private
     * @param {Object} source The object to copy properties from.
     * @param {Array} props The property names to copy.
     * @param {Object} [object={}] The object to copy properties to.
     * @returns {Object} Returns `object`.
     */
    function baseCopy(source, props, object) {
      object || (object = {});

      var index = -1,
          length = props.length;

      while (++index < length) {
        var key = props[index];
        object[key] = source[key];
      }
      return object;
    }

    /**
     * The base implementation of `_.callback` which supports specifying the
     * number of arguments to provide to `func`.
     *
     * @private
     * @param {*} [func=_.identity] The value to convert to a callback.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {number} [argCount] The number of arguments to provide to `func`.
     * @returns {Function} Returns the callback.
     */
    function baseCallback(func, thisArg, argCount) {
      var type = typeof func;
      if (type == 'function') {
        return thisArg === undefined
          ? func
          : bindCallback(func, thisArg, argCount);
      }
      if (func == null) {
        return identity;
      }
      if (type == 'object') {
        return baseMatches(func);
      }
      return thisArg === undefined
        ? property(func)
        : baseMatchesProperty(func, thisArg);
    }

    /**
     * The base implementation of `_.clone` without support for argument juggling
     * and `this` binding `customizer` functions.
     *
     * @private
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep] Specify a deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {string} [key] The key of `value`.
     * @param {Object} [object] The object `value` belongs to.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates clones with source counterparts.
     * @returns {*} Returns the cloned value.
     */
    function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
      var result;
      if (customizer) {
        result = object ? customizer(value, key, object) : customizer(value);
      }
      if (result !== undefined) {
        return result;
      }
      if (!isObject(value)) {
        return value;
      }
      var isArr = isArray(value);
      if (isArr) {
        result = initCloneArray(value);
        if (!isDeep) {
          return arrayCopy(value, result);
        }
      } else {
        var tag = objToString.call(value),
            isFunc = tag == funcTag;

        if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
          result = initCloneObject(isFunc ? {} : value);
          if (!isDeep) {
            return baseAssign(result, value);
          }
        } else {
          return cloneableTags[tag]
            ? initCloneByTag(value, tag, isDeep)
            : (object ? value : {});
        }
      }
      // Check for circular references and return corresponding clone.
      stackA || (stackA = []);
      stackB || (stackB = []);

      var length = stackA.length;
      while (length--) {
        if (stackA[length] == value) {
          return stackB[length];
        }
      }
      // Add the source value to the stack of traversed objects and associate it with its clone.
      stackA.push(value);
      stackB.push(result);

      // Recursively populate clone (susceptible to call stack limits).
      (isArr ? arrayEach : baseForOwn)(value, function(subValue, key) {
        result[key] = baseClone(subValue, isDeep, customizer, key, value, stackA, stackB);
      });
      return result;
    }

    /**
     * The base implementation of `_.create` without support for assigning
     * properties to the created object.
     *
     * @private
     * @param {Object} prototype The object to inherit from.
     * @returns {Object} Returns the new object.
     */
    var baseCreate = (function() {
      function Object() {}
      return function(prototype) {
        if (isObject(prototype)) {
          Object.prototype = prototype;
          var result = new Object;
          Object.prototype = null;
        }
        return result || context.Object();
      };
    }());

    /**
     * The base implementation of `_.delay` and `_.defer` which accepts an index
     * of where to slice the arguments to provide to `func`.
     *
     * @private
     * @param {Function} func The function to delay.
     * @param {number} wait The number of milliseconds to delay invocation.
     * @param {Object} args The arguments provide to `func`.
     * @returns {number} Returns the timer id.
     */
    function baseDelay(func, wait, args) {
      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return setTimeout(function() { func.apply(undefined, args); }, wait);
    }

    /**
     * The base implementation of `_.difference` which accepts a single array
     * of values to exclude.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {Array} values The values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     */
    function baseDifference(array, values) {
      var length = array ? array.length : 0,
          result = [];

      if (!length) {
        return result;
      }
      var index = -1,
          indexOf = getIndexOf(),
          isCommon = indexOf == baseIndexOf,
          cache = (isCommon && values.length >= 200) ? createCache(values) : null,
          valuesLength = values.length;

      if (cache) {
        indexOf = cacheIndexOf;
        isCommon = false;
        values = cache;
      }
      outer:
      while (++index < length) {
        var value = array[index];

        if (isCommon && value === value) {
          var valuesIndex = valuesLength;
          while (valuesIndex--) {
            if (values[valuesIndex] === value) {
              continue outer;
            }
          }
          result.push(value);
        }
        else if (indexOf(values, value, 0) < 0) {
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.forEach` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array|Object|string} Returns `collection`.
     */
    var baseEach = createBaseEach(baseForOwn);

    /**
     * The base implementation of `_.forEachRight` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array|Object|string} Returns `collection`.
     */
    var baseEachRight = createBaseEach(baseForOwnRight, true);

    /**
     * The base implementation of `_.every` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`
     */
    function baseEvery(collection, predicate) {
      var result = true;
      baseEach(collection, function(value, index, collection) {
        result = !!predicate(value, index, collection);
        return result;
      });
      return result;
    }

    /**
     * The base implementation of `_.fill` without an iteratee call guard.
     *
     * @private
     * @param {Array} array The array to fill.
     * @param {*} value The value to fill `array` with.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns `array`.
     */
    function baseFill(array, value, start, end) {
      var length = array.length;

      start = start == null ? 0 : (+start || 0);
      if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
      end = (end === undefined || end > length) ? length : (+end || 0);
      if (end < 0) {
        end += length;
      }
      length = start > end ? 0 : (end >>> 0);
      start >>>= 0;

      while (start < length) {
        array[start++] = value;
      }
      return array;
    }

    /**
     * The base implementation of `_.filter` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Array} Returns the new filtered array.
     */
    function baseFilter(collection, predicate) {
      var result = [];
      baseEach(collection, function(value, index, collection) {
        if (predicate(value, index, collection)) {
          result.push(value);
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.find`, `_.findLast`, `_.findKey`, and `_.findLastKey`,
     * without support for callback shorthands and `this` binding, which iterates
     * over `collection` using the provided `eachFunc`.
     *
     * @private
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function} predicate The function invoked per iteration.
     * @param {Function} eachFunc The function to iterate over `collection`.
     * @param {boolean} [retKey] Specify returning the key of the found element
     *  instead of the element itself.
     * @returns {*} Returns the found element or its key, else `undefined`.
     */
    function baseFind(collection, predicate, eachFunc, retKey) {
      var result;
      eachFunc(collection, function(value, key, collection) {
        if (predicate(value, key, collection)) {
          result = retKey ? key : value;
          return false;
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.flatten` with added support for restricting
     * flattening and specifying the start index.
     *
     * @private
     * @param {Array} array The array to flatten.
     * @param {boolean} isDeep Specify a deep flatten.
     * @param {boolean} isStrict Restrict flattening to arrays and `arguments` objects.
     * @returns {Array} Returns the new flattened array.
     */
    function baseFlatten(array, isDeep, isStrict) {
      var index = -1,
          length = array.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];

        if (isObjectLike(value) && isLength(value.length) && (isArray(value) || isArguments(value))) {
          if (isDeep) {
            // Recursively flatten arrays (susceptible to call stack limits).
            value = baseFlatten(value, isDeep, isStrict);
          }
          var valIndex = -1,
              valLength = value.length;

          result.length += valLength;
          while (++valIndex < valLength) {
            result[++resIndex] = value[valIndex];
          }
        } else if (!isStrict) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * The base implementation of `baseForIn` and `baseForOwn` which iterates
     * over `object` properties returned by `keysFunc` invoking `iteratee` for
     * each property. Iteratee functions may exit iteration early by explicitly
     * returning `false`.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns `object`.
     */
    var baseFor = createBaseFor();

    /**
     * This function is like `baseFor` except that it iterates over properties
     * in the opposite order.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns `object`.
     */
    var baseForRight = createBaseFor(true);

    /**
     * The base implementation of `_.forIn` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForIn(object, iteratee) {
      return baseFor(object, iteratee, keysIn);
    }

    /**
     * The base implementation of `_.forOwn` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForOwn(object, iteratee) {
      return baseFor(object, iteratee, keys);
    }

    /**
     * The base implementation of `_.forOwnRight` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForOwnRight(object, iteratee) {
      return baseForRight(object, iteratee, keys);
    }

    /**
     * The base implementation of `_.functions` which creates an array of
     * `object` function property names filtered from those provided.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @param {Array} props The property names to filter.
     * @returns {Array} Returns the new array of filtered property names.
     */
    function baseFunctions(object, props) {
      var index = -1,
          length = props.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var key = props[index];
        if (isFunction(object[key])) {
          result[++resIndex] = key;
        }
      }
      return result;
    }

    /**
     * The base implementation of `get` without support for string paths
     * and default values.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {Array} path The path of the property to get.
     * @param {string} [pathKey] The key representation of path.
     * @returns {*} Returns the resolved value.
     */
    function baseGet(object, path, pathKey) {
      if (object == null) {
        return;
      }
      if (pathKey !== undefined && pathKey in toObject(object)) {
        path = [pathKey];
      }
      var index = -1,
          length = path.length;

      while (object != null && ++index < length) {
        var result = object = object[path[index]];
      }
      return result;
    }

    /**
     * The base implementation of `_.isEqual` without support for `this` binding
     * `customizer` functions.
     *
     * @private
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @param {Function} [customizer] The function to customize comparing values.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA] Tracks traversed `value` objects.
     * @param {Array} [stackB] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
     */
    function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
      // Exit early for identical values.
      if (value === other) {
        // Treat `+0` vs. `-0` as not equal.
        return value !== 0 || (1 / value == 1 / other);
      }
      var valType = typeof value,
          othType = typeof other;

      // Exit early for unlike primitive values.
      if ((valType != 'function' && valType != 'object' && othType != 'function' && othType != 'object') ||
          value == null || other == null) {
        // Return `false` unless both values are `NaN`.
        return value !== value && other !== other;
      }
      return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);
    }

    /**
     * A specialized version of `baseIsEqual` for arrays and objects which performs
     * deep comparisons and tracks traversed objects enabling objects with circular
     * references to be compared.
     *
     * @private
     * @param {Object} object The object to compare.
     * @param {Object} other The other object to compare.
     * @param {Function} equalFunc The function to determine equivalents of values.
     * @param {Function} [customizer] The function to customize comparing objects.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA=[]] Tracks traversed `value` objects.
     * @param {Array} [stackB=[]] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
      var objIsArr = isArray(object),
          othIsArr = isArray(other),
          objTag = arrayTag,
          othTag = arrayTag;

      if (!objIsArr) {
        objTag = objToString.call(object);
        if (objTag == argsTag) {
          objTag = objectTag;
        } else if (objTag != objectTag) {
          objIsArr = isTypedArray(object);
        }
      }
      if (!othIsArr) {
        othTag = objToString.call(other);
        if (othTag == argsTag) {
          othTag = objectTag;
        } else if (othTag != objectTag) {
          othIsArr = isTypedArray(other);
        }
      }
      var objIsObj = objTag == objectTag,
          othIsObj = othTag == objectTag,
          isSameTag = objTag == othTag;

      if (isSameTag && !(objIsArr || objIsObj)) {
        return equalByTag(object, other, objTag);
      }
      if (!isLoose) {
        var valWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
            othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

        if (valWrapped || othWrapped) {
          return equalFunc(valWrapped ? object.value() : object, othWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
        }
      }
      if (!isSameTag) {
        return false;
      }
      // Assume cyclic values are equal.
      // For more information on detecting circular references see https://es5.github.io/#JO.
      stackA || (stackA = []);
      stackB || (stackB = []);

      var length = stackA.length;
      while (length--) {
        if (stackA[length] == object) {
          return stackB[length] == other;
        }
      }
      // Add `object` and `other` to the stack of traversed objects.
      stackA.push(object);
      stackB.push(other);

      var result = (objIsArr ? equalArrays : equalObjects)(object, other, equalFunc, customizer, isLoose, stackA, stackB);

      stackA.pop();
      stackB.pop();

      return result;
    }

    /**
     * The base implementation of `_.isMatch` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @param {Array} props The source property names to match.
     * @param {Array} values The source values to match.
     * @param {Array} strictCompareFlags Strict comparison flags for source values.
     * @param {Function} [customizer] The function to customize comparing objects.
     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
     */
    function baseIsMatch(object, props, values, strictCompareFlags, customizer) {
      var index = -1,
          length = props.length,
          noCustomizer = !customizer;

      while (++index < length) {
        if ((noCustomizer && strictCompareFlags[index])
              ? values[index] !== object[props[index]]
              : !(props[index] in object)
            ) {
          return false;
        }
      }
      index = -1;
      while (++index < length) {
        var key = props[index],
            objValue = object[key],
            srcValue = values[index];

        if (noCustomizer && strictCompareFlags[index]) {
          var result = objValue !== undefined || (key in object);
        } else {
          result = customizer ? customizer(objValue, srcValue, key) : undefined;
          if (result === undefined) {
            result = baseIsEqual(srcValue, objValue, customizer, true);
          }
        }
        if (!result) {
          return false;
        }
      }
      return true;
    }

    /**
     * The base implementation of `_.map` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns the new mapped array.
     */
    function baseMap(collection, iteratee) {
      var index = -1,
          length = getLength(collection),
          result = isLength(length) ? Array(length) : [];

      baseEach(collection, function(value, key, collection) {
        result[++index] = iteratee(value, key, collection);
      });
      return result;
    }

    /**
     * The base implementation of `_.matches` which does not clone `source`.
     *
     * @private
     * @param {Object} source The object of property values to match.
     * @returns {Function} Returns the new function.
     */
    function baseMatches(source) {
      var props = keys(source),
          length = props.length;

      if (!length) {
        return constant(true);
      }
      if (length == 1) {
        var key = props[0],
            value = source[key];

        if (isStrictComparable(value)) {
          return function(object) {
            if (object == null) {
              return false;
            }
            return object[key] === value && (value !== undefined || (key in toObject(object)));
          };
        }
      }
      var values = Array(length),
          strictCompareFlags = Array(length);

      while (length--) {
        value = source[props[length]];
        values[length] = value;
        strictCompareFlags[length] = isStrictComparable(value);
      }
      return function(object) {
        return object != null && baseIsMatch(toObject(object), props, values, strictCompareFlags);
      };
    }

    /**
     * The base implementation of `_.matchesProperty` which does not which does
     * not clone `value`.
     *
     * @private
     * @param {string} path The path of the property to get.
     * @param {*} value The value to compare.
     * @returns {Function} Returns the new function.
     */
    function baseMatchesProperty(path, value) {
      var isArr = isArray(path),
          isCommon = isKey(path) && isStrictComparable(value),
          pathKey = (path + '');

      path = toPath(path);
      return function(object) {
        if (object == null) {
          return false;
        }
        var key = pathKey;
        object = toObject(object);
        if ((isArr || !isCommon) && !(key in object)) {
          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
          if (object == null) {
            return false;
          }
          key = last(path);
          object = toObject(object);
        }
        return object[key] === value
          ? (value !== undefined || (key in object))
          : baseIsEqual(value, object[key], null, true);
      };
    }

    /**
     * The base implementation of `_.merge` without support for argument juggling,
     * multiple sources, and `this` binding `customizer` functions.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {Function} [customizer] The function to customize merging properties.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates values with source counterparts.
     * @returns {Object} Returns `object`.
     */
    function baseMerge(object, source, customizer, stackA, stackB) {
      if (!isObject(object)) {
        return object;
      }
      var isSrcArr = isLength(source.length) && (isArray(source) || isTypedArray(source));
      if (!isSrcArr) {
        var props = keys(source);
        push.apply(props, getSymbols(source));
      }
      arrayEach(props || source, function(srcValue, key) {
        if (props) {
          key = srcValue;
          srcValue = source[key];
        }
        if (isObjectLike(srcValue)) {
          stackA || (stackA = []);
          stackB || (stackB = []);
          baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
        }
        else {
          var value = object[key],
              result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
              isCommon = result === undefined;

          if (isCommon) {
            result = srcValue;
          }
          if ((isSrcArr || result !== undefined) &&
              (isCommon || (result === result ? (result !== value) : (value === value)))) {
            object[key] = result;
          }
        }
      });
      return object;
    }

    /**
     * A specialized version of `baseMerge` for arrays and objects which performs
     * deep merges and tracks traversed objects enabling objects with circular
     * references to be merged.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {string} key The key of the value to merge.
     * @param {Function} mergeFunc The function to merge values.
     * @param {Function} [customizer] The function to customize merging properties.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates values with source counterparts.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stackB) {
      var length = stackA.length,
          srcValue = source[key];

      while (length--) {
        if (stackA[length] == srcValue) {
          object[key] = stackB[length];
          return;
        }
      }
      var value = object[key],
          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
          isCommon = result === undefined;

      if (isCommon) {
        result = srcValue;
        if (isLength(srcValue.length) && (isArray(srcValue) || isTypedArray(srcValue))) {
          result = isArray(value)
            ? value
            : (getLength(value) ? arrayCopy(value) : []);
        }
        else if (isPlainObject(srcValue) || isArguments(srcValue)) {
          result = isArguments(value)
            ? toPlainObject(value)
            : (isPlainObject(value) ? value : {});
        }
        else {
          isCommon = false;
        }
      }
      // Add the source value to the stack of traversed objects and associate
      // it with its merged value.
      stackA.push(srcValue);
      stackB.push(result);

      if (isCommon) {
        // Recursively merge objects and arrays (susceptible to call stack limits).
        object[key] = mergeFunc(result, srcValue, customizer, stackA, stackB);
      } else if (result === result ? (result !== value) : (value === value)) {
        object[key] = result;
      }
    }

    /**
     * The base implementation of `_.property` without support for deep paths.
     *
     * @private
     * @param {string} key The key of the property to get.
     * @returns {Function} Returns the new function.
     */
    function baseProperty(key) {
      return function(object) {
        return object == null ? undefined : object[key];
      };
    }

    /**
     * A specialized version of `baseProperty` which supports deep paths.
     *
     * @private
     * @param {Array|string} path The path of the property to get.
     * @returns {Function} Returns the new function.
     */
    function basePropertyDeep(path) {
      var pathKey = (path + '');
      path = toPath(path);
      return function(object) {
        return baseGet(object, path, pathKey);
      };
    }

    /**
     * The base implementation of `_.pullAt` without support for individual
     * index arguments and capturing the removed elements.
     *
     * @private
     * @param {Array} array The array to modify.
     * @param {number[]} indexes The indexes of elements to remove.
     * @returns {Array} Returns `array`.
     */
    function basePullAt(array, indexes) {
      var length = indexes.length;
      while (length--) {
        var index = parseFloat(indexes[length]);
        if (index != previous && isIndex(index)) {
          var previous = index;
          splice.call(array, index, 1);
        }
      }
      return array;
    }

    /**
     * The base implementation of `_.random` without support for argument juggling
     * and returning floating-point numbers.
     *
     * @private
     * @param {number} min The minimum possible value.
     * @param {number} max The maximum possible value.
     * @returns {number} Returns the random number.
     */
    function baseRandom(min, max) {
      return min + floor(nativeRandom() * (max - min + 1));
    }

    /**
     * The base implementation of `_.reduce` and `_.reduceRight` without support
     * for callback shorthands and `this` binding, which iterates over `collection`
     * using the provided `eachFunc`.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} accumulator The initial value.
     * @param {boolean} initFromCollection Specify using the first or last element
     *  of `collection` as the initial value.
     * @param {Function} eachFunc The function to iterate over `collection`.
     * @returns {*} Returns the accumulated value.
     */
    function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
      eachFunc(collection, function(value, index, collection) {
        accumulator = initFromCollection
          ? (initFromCollection = false, value)
          : iteratee(accumulator, value, index, collection);
      });
      return accumulator;
    }

    /**
     * The base implementation of `setData` without support for hot loop detection.
     *
     * @private
     * @param {Function} func The function to associate metadata with.
     * @param {*} data The metadata.
     * @returns {Function} Returns `func`.
     */
    var baseSetData = !metaMap ? identity : function(func, data) {
      metaMap.set(func, data);
      return func;
    };

    /**
     * The base implementation of `_.slice` without an iteratee call guard.
     *
     * @private
     * @param {Array} array The array to slice.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns the slice of `array`.
     */
    function baseSlice(array, start, end) {
      var index = -1,
          length = array.length;

      start = start == null ? 0 : (+start || 0);
      if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
      end = (end === undefined || end > length) ? length : (+end || 0);
      if (end < 0) {
        end += length;
      }
      length = start > end ? 0 : ((end - start) >>> 0);
      start >>>= 0;

      var result = Array(length);
      while (++index < length) {
        result[index] = array[index + start];
      }
      return result;
    }

    /**
     * The base implementation of `_.some` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     */
    function baseSome(collection, predicate) {
      var result;

      baseEach(collection, function(value, index, collection) {
        result = predicate(value, index, collection);
        return !result;
      });
      return !!result;
    }

    /**
     * The base implementation of `_.sortBy` which uses `comparer` to define
     * the sort order of `array` and replaces criteria objects with their
     * corresponding values.
     *
     * @private
     * @param {Array} array The array to sort.
     * @param {Function} comparer The function to define sort order.
     * @returns {Array} Returns `array`.
     */
    function baseSortBy(array, comparer) {
      var length = array.length;

      array.sort(comparer);
      while (length--) {
        array[length] = array[length].value;
      }
      return array;
    }

    /**
     * The base implementation of `_.sortByOrder` without param guards.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
     * @param {boolean[]} orders The sort orders of `iteratees`.
     * @returns {Array} Returns the new sorted array.
     */
    function baseSortByOrder(collection, iteratees, orders) {
      var callback = getCallback(),
          index = -1;

      iteratees = arrayMap(iteratees, function(iteratee) { return callback(iteratee); });

      var result = baseMap(collection, function(value) {
        var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
        return { 'criteria': criteria, 'index': ++index, 'value': value };
      });

      return baseSortBy(result, function(object, other) {
        return compareMultiple(object, other, orders);
      });
    }

    /**
     * The base implementation of `_.sum` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {number} Returns the sum.
     */
    function baseSum(collection, iteratee) {
      var result = 0;
      baseEach(collection, function(value, index, collection) {
        result += +iteratee(value, index, collection) || 0;
      });
      return result;
    }

    /**
     * The base implementation of `_.uniq` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {Function} [iteratee] The function invoked per iteration.
     * @returns {Array} Returns the new duplicate-value-free array.
     */
    function baseUniq(array, iteratee) {
      var index = -1,
          indexOf = getIndexOf(),
          length = array.length,
          isCommon = indexOf == baseIndexOf,
          isLarge = isCommon && length >= 200,
          seen = isLarge ? createCache() : null,
          result = [];

      if (seen) {
        indexOf = cacheIndexOf;
        isCommon = false;
      } else {
        isLarge = false;
        seen = iteratee ? [] : result;
      }
      outer:
      while (++index < length) {
        var value = array[index],
            computed = iteratee ? iteratee(value, index, array) : value;

        if (isCommon && value === value) {
          var seenIndex = seen.length;
          while (seenIndex--) {
            if (seen[seenIndex] === computed) {
              continue outer;
            }
          }
          if (iteratee) {
            seen.push(computed);
          }
          result.push(value);
        }
        else if (indexOf(seen, computed, 0) < 0) {
          if (iteratee || isLarge) {
            seen.push(computed);
          }
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.values` and `_.valuesIn` which creates an
     * array of `object` property values corresponding to the property names
     * of `props`.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {Array} props The property names to get values for.
     * @returns {Object} Returns the array of property values.
     */
    function baseValues(object, props) {
      var index = -1,
          length = props.length,
          result = Array(length);

      while (++index < length) {
        result[index] = object[props[index]];
      }
      return result;
    }

    /**
     * The base implementation of `_.dropRightWhile`, `_.dropWhile`, `_.takeRightWhile`,
     * and `_.takeWhile` without support for callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to query.
     * @param {Function} predicate The function invoked per iteration.
     * @param {boolean} [isDrop] Specify dropping elements instead of taking them.
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Array} Returns the slice of `array`.
     */
    function baseWhile(array, predicate, isDrop, fromRight) {
      var length = array.length,
          index = fromRight ? length : -1;

      while ((fromRight ? index-- : ++index < length) && predicate(array[index], index, array)) {}
      return isDrop
        ? baseSlice(array, (fromRight ? 0 : index), (fromRight ? index + 1 : length))
        : baseSlice(array, (fromRight ? index + 1 : 0), (fromRight ? length : index));
    }

    /**
     * The base implementation of `wrapperValue` which returns the result of
     * performing a sequence of actions on the unwrapped `value`, where each
     * successive action is supplied the return value of the previous.
     *
     * @private
     * @param {*} value The unwrapped value.
     * @param {Array} actions Actions to peform to resolve the unwrapped value.
     * @returns {*} Returns the resolved value.
     */
    function baseWrapperValue(value, actions) {
      var result = value;
      if (result instanceof LazyWrapper) {
        result = result.value();
      }
      var index = -1,
          length = actions.length;

      while (++index < length) {
        var args = [result],
            action = actions[index];

        push.apply(args, action.args);
        result = action.func.apply(action.thisArg, args);
      }
      return result;
    }

    /**
     * Performs a binary search of `array` to determine the index at which `value`
     * should be inserted into `array` in order to maintain its sort order.
     *
     * @private
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {boolean} [retHighest] Specify returning the highest qualified index.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     */
    function binaryIndex(array, value, retHighest) {
      var low = 0,
          high = array ? array.length : low;

      if (typeof value == 'number' && value === value && high <= HALF_MAX_ARRAY_LENGTH) {
        while (low < high) {
          var mid = (low + high) >>> 1,
              computed = array[mid];

          if (retHighest ? (computed <= value) : (computed < value)) {
            low = mid + 1;
          } else {
            high = mid;
          }
        }
        return high;
      }
      return binaryIndexBy(array, value, identity, retHighest);
    }

    /**
     * This function is like `binaryIndex` except that it invokes `iteratee` for
     * `value` and each element of `array` to compute their sort ranking. The
     * iteratee is invoked with one argument; (value).
     *
     * @private
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {boolean} [retHighest] Specify returning the highest qualified index.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     */
    function binaryIndexBy(array, value, iteratee, retHighest) {
      value = iteratee(value);

      var low = 0,
          high = array ? array.length : 0,
          valIsNaN = value !== value,
          valIsUndef = value === undefined;

      while (low < high) {
        var mid = floor((low + high) / 2),
            computed = iteratee(array[mid]),
            isReflexive = computed === computed;

        if (valIsNaN) {
          var setLow = isReflexive || retHighest;
        } else if (valIsUndef) {
          setLow = isReflexive && (retHighest || computed !== undefined);
        } else {
          setLow = retHighest ? (computed <= value) : (computed < value);
        }
        if (setLow) {
          low = mid + 1;
        } else {
          high = mid;
        }
      }
      return nativeMin(high, MAX_ARRAY_INDEX);
    }

    /**
     * A specialized version of `baseCallback` which only supports `this` binding
     * and specifying the number of arguments to provide to `func`.
     *
     * @private
     * @param {Function} func The function to bind.
     * @param {*} thisArg The `this` binding of `func`.
     * @param {number} [argCount] The number of arguments to provide to `func`.
     * @returns {Function} Returns the callback.
     */
    function bindCallback(func, thisArg, argCount) {
      if (typeof func != 'function') {
        return identity;
      }
      if (thisArg === undefined) {
        return func;
      }
      switch (argCount) {
        case 1: return function(value) {
          return func.call(thisArg, value);
        };
        case 3: return function(value, index, collection) {
          return func.call(thisArg, value, index, collection);
        };
        case 4: return function(accumulator, value, index, collection) {
          return func.call(thisArg, accumulator, value, index, collection);
        };
        case 5: return function(value, other, key, object, source) {
          return func.call(thisArg, value, other, key, object, source);
        };
      }
      return function() {
        return func.apply(thisArg, arguments);
      };
    }

    /**
     * Creates a clone of the given array buffer.
     *
     * @private
     * @param {ArrayBuffer} buffer The array buffer to clone.
     * @returns {ArrayBuffer} Returns the cloned array buffer.
     */
    function bufferClone(buffer) {
      return bufferSlice.call(buffer, 0);
    }
    if (!bufferSlice) {
      // PhantomJS has `ArrayBuffer` and `Uint8Array` but not `Float64Array`.
      bufferClone = !(ArrayBuffer && Uint8Array) ? constant(null) : function(buffer) {
        var byteLength = buffer.byteLength,
            floatLength = Float64Array ? floor(byteLength / FLOAT64_BYTES_PER_ELEMENT) : 0,
            offset = floatLength * FLOAT64_BYTES_PER_ELEMENT,
            result = new ArrayBuffer(byteLength);

        if (floatLength) {
          var view = new Float64Array(result, 0, floatLength);
          view.set(new Float64Array(buffer, 0, floatLength));
        }
        if (byteLength != offset) {
          view = new Uint8Array(result, offset);
          view.set(new Uint8Array(buffer, offset));
        }
        return result;
      };
    }

    /**
     * Creates an array that is the composition of partially applied arguments,
     * placeholders, and provided arguments into a single array of arguments.
     *
     * @private
     * @param {Array|Object} args The provided arguments.
     * @param {Array} partials The arguments to prepend to those provided.
     * @param {Array} holders The `partials` placeholder indexes.
     * @returns {Array} Returns the new array of composed arguments.
     */
    function composeArgs(args, partials, holders) {
      var holdersLength = holders.length,
          argsIndex = -1,
          argsLength = nativeMax(args.length - holdersLength, 0),
          leftIndex = -1,
          leftLength = partials.length,
          result = Array(argsLength + leftLength);

      while (++leftIndex < leftLength) {
        result[leftIndex] = partials[leftIndex];
      }
      while (++argsIndex < holdersLength) {
        result[holders[argsIndex]] = args[argsIndex];
      }
      while (argsLength--) {
        result[leftIndex++] = args[argsIndex++];
      }
      return result;
    }

    /**
     * This function is like `composeArgs` except that the arguments composition
     * is tailored for `_.partialRight`.
     *
     * @private
     * @param {Array|Object} args The provided arguments.
     * @param {Array} partials The arguments to append to those provided.
     * @param {Array} holders The `partials` placeholder indexes.
     * @returns {Array} Returns the new array of composed arguments.
     */
    function composeArgsRight(args, partials, holders) {
      var holdersIndex = -1,
          holdersLength = holders.length,
          argsIndex = -1,
          argsLength = nativeMax(args.length - holdersLength, 0),
          rightIndex = -1,
          rightLength = partials.length,
          result = Array(argsLength + rightLength);

      while (++argsIndex < argsLength) {
        result[argsIndex] = args[argsIndex];
      }
      var pad = argsIndex;
      while (++rightIndex < rightLength) {
        result[pad + rightIndex] = partials[rightIndex];
      }
      while (++holdersIndex < holdersLength) {
        result[pad + holders[holdersIndex]] = args[argsIndex++];
      }
      return result;
    }

    /**
     * Creates a function that aggregates a collection, creating an accumulator
     * object composed from the results of running each element in the collection
     * through an iteratee.
     *
     * **Note:** This function is used to create `_.countBy`, `_.groupBy`, `_.indexBy`,
     * and `_.partition`.
     *
     * @private
     * @param {Function} setter The function to set keys and values of the accumulator object.
     * @param {Function} [initializer] The function to initialize the accumulator object.
     * @returns {Function} Returns the new aggregator function.
     */
    function createAggregator(setter, initializer) {
      return function(collection, iteratee, thisArg) {
        var result = initializer ? initializer() : {};
        iteratee = getCallback(iteratee, thisArg, 3);

        if (isArray(collection)) {
          var index = -1,
              length = collection.length;

          while (++index < length) {
            var value = collection[index];
            setter(result, value, iteratee(value, index, collection), collection);
          }
        } else {
          baseEach(collection, function(value, key, collection) {
            setter(result, value, iteratee(value, key, collection), collection);
          });
        }
        return result;
      };
    }

    /**
     * Creates a function that assigns properties of source object(s) to a given
     * destination object.
     *
     * **Note:** This function is used to create `_.assign`, `_.defaults`, and `_.merge`.
     *
     * @private
     * @param {Function} assigner The function to assign values.
     * @returns {Function} Returns the new assigner function.
     */
    function createAssigner(assigner) {
      return restParam(function(object, sources) {
        var index = -1,
            length = object == null ? 0 : sources.length,
            customizer = length > 2 && sources[length - 2],
            guard = length > 2 && sources[2],
            thisArg = length > 1 && sources[length - 1];

        if (typeof customizer == 'function') {
          customizer = bindCallback(customizer, thisArg, 5);
          length -= 2;
        } else {
          customizer = typeof thisArg == 'function' ? thisArg : null;
          length -= (customizer ? 1 : 0);
        }
        if (guard && isIterateeCall(sources[0], sources[1], guard)) {
          customizer = length < 3 ? null : customizer;
          length = 1;
        }
        while (++index < length) {
          var source = sources[index];
          if (source) {
            assigner(object, source, customizer);
          }
        }
        return object;
      });
    }

    /**
     * Creates a `baseEach` or `baseEachRight` function.
     *
     * @private
     * @param {Function} eachFunc The function to iterate over a collection.
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new base function.
     */
    function createBaseEach(eachFunc, fromRight) {
      return function(collection, iteratee) {
        var length = collection ? getLength(collection) : 0;
        if (!isLength(length)) {
          return eachFunc(collection, iteratee);
        }
        var index = fromRight ? length : -1,
            iterable = toObject(collection);

        while ((fromRight ? index-- : ++index < length)) {
          if (iteratee(iterable[index], index, iterable) === false) {
            break;
          }
        }
        return collection;
      };
    }

    /**
     * Creates a base function for `_.forIn` or `_.forInRight`.
     *
     * @private
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new base function.
     */
    function createBaseFor(fromRight) {
      return function(object, iteratee, keysFunc) {
        var iterable = toObject(object),
            props = keysFunc(object),
            length = props.length,
            index = fromRight ? length : -1;

        while ((fromRight ? index-- : ++index < length)) {
          var key = props[index];
          if (iteratee(iterable[key], key, iterable) === false) {
            break;
          }
        }
        return object;
      };
    }

    /**
     * Creates a function that wraps `func` and invokes it with the `this`
     * binding of `thisArg`.
     *
     * @private
     * @param {Function} func The function to bind.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @returns {Function} Returns the new bound function.
     */
    function createBindWrapper(func, thisArg) {
      var Ctor = createCtorWrapper(func);

      function wrapper() {
        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
        return fn.apply(thisArg, arguments);
      }
      return wrapper;
    }

    /**
     * Creates a `Set` cache object to optimize linear searches of large arrays.
     *
     * @private
     * @param {Array} [values] The values to cache.
     * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
     */
    var createCache = !(nativeCreate && Set) ? constant(null) : function(values) {
      return new SetCache(values);
    };

    /**
     * Creates a function that produces compound words out of the words in a
     * given string.
     *
     * @private
     * @param {Function} callback The function to combine each word.
     * @returns {Function} Returns the new compounder function.
     */
    function createCompounder(callback) {
      return function(string) {
        var index = -1,
            array = words(deburr(string)),
            length = array.length,
            result = '';

        while (++index < length) {
          result = callback(result, array[index], index);
        }
        return result;
      };
    }

    /**
     * Creates a function that produces an instance of `Ctor` regardless of
     * whether it was invoked as part of a `new` expression or by `call` or `apply`.
     *
     * @private
     * @param {Function} Ctor The constructor to wrap.
     * @returns {Function} Returns the new wrapped function.
     */
    function createCtorWrapper(Ctor) {
      return function() {
        var thisBinding = baseCreate(Ctor.prototype),
            result = Ctor.apply(thisBinding, arguments);

        // Mimic the constructor's `return` behavior.
        // See https://es5.github.io/#x13.2.2 for more details.
        return isObject(result) ? result : thisBinding;
      };
    }

    /**
     * Creates a `_.curry` or `_.curryRight` function.
     *
     * @private
     * @param {boolean} flag The curry bit flag.
     * @returns {Function} Returns the new curry function.
     */
    function createCurry(flag) {
      function curryFunc(func, arity, guard) {
        if (guard && isIterateeCall(func, arity, guard)) {
          arity = null;
        }
        var result = createWrapper(func, flag, null, null, null, null, null, arity);
        result.placeholder = curryFunc.placeholder;
        return result;
      }
      return curryFunc;
    }

    /**
     * Creates a `_.max` or `_.min` function.
     *
     * @private
     * @param {Function} arrayFunc The function to get the extremum value from an array.
     * @param {boolean} [isMin] Specify returning the minimum, instead of the maximum,
     *  extremum value.
     * @returns {Function} Returns the new extremum function.
     */
    function createExtremum(arrayFunc, isMin) {
      return function(collection, iteratee, thisArg) {
        if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
          iteratee = null;
        }
        var func = getCallback(),
            noIteratee = iteratee == null;

        if (!(func === baseCallback && noIteratee)) {
          noIteratee = false;
          iteratee = func(iteratee, thisArg, 3);
        }
        if (noIteratee) {
          var isArr = isArray(collection);
          if (!isArr && isString(collection)) {
            iteratee = charAtCallback;
          } else {
            return arrayFunc(isArr ? collection : toIterable(collection));
          }
        }
        return extremumBy(collection, iteratee, isMin);
      };
    }

    /**
     * Creates a `_.find` or `_.findLast` function.
     *
     * @private
     * @param {Function} eachFunc The function to iterate over a collection.
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new find function.
     */
    function createFind(eachFunc, fromRight) {
      return function(collection, predicate, thisArg) {
        predicate = getCallback(predicate, thisArg, 3);
        if (isArray(collection)) {
          var index = baseFindIndex(collection, predicate, fromRight);
          return index > -1 ? collection[index] : undefined;
        }
        return baseFind(collection, predicate, eachFunc);
      }
    }

    /**
     * Creates a `_.findIndex` or `_.findLastIndex` function.
     *
     * @private
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new find function.
     */
    function createFindIndex(fromRight) {
      return function(array, predicate, thisArg) {
        if (!(array && array.length)) {
          return -1;
        }
        predicate = getCallback(predicate, thisArg, 3);
        return baseFindIndex(array, predicate, fromRight);
      };
    }

    /**
     * Creates a `_.findKey` or `_.findLastKey` function.
     *
     * @private
     * @param {Function} objectFunc The function to iterate over an object.
     * @returns {Function} Returns the new find function.
     */
    function createFindKey(objectFunc) {
      return function(object, predicate, thisArg) {
        predicate = getCallback(predicate, thisArg, 3);
        return baseFind(object, predicate, objectFunc, true);
      };
    }

    /**
     * Creates a `_.flow` or `_.flowRight` function.
     *
     * @private
     * @param {boolean} [fromRight] Specify iterating from right to left.
     * @returns {Function} Returns the new flow function.
     */
    function createFlow(fromRight) {
      return function() {
        var length = arguments.length;
        if (!length) {
          return function() { return arguments[0]; };
        }
        var wrapper,
            index = fromRight ? length : -1,
            leftIndex = 0,
            funcs = Array(length);

        while ((fromRight ? index-- : ++index < length)) {
          var func = funcs[leftIndex++] = arguments[index];
          if (typeof func != 'function') {
            throw new TypeError(FUNC_ERROR_TEXT);
          }
          var funcName = wrapper ? '' : getFuncName(func);
          wrapper = funcName == 'wrapper' ? new LodashWrapper([]) : wrapper;
        }
        index = wrapper ? -1 : length;
        while (++index < length) {
          func = funcs[index];
          funcName = getFuncName(func);

          var data = funcName == 'wrapper' ? getData(func) : null;
          if (data && isLaziable(data[0])) {
            wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
          } else {
            wrapper = (func.length == 1 && isLaziable(func)) ? wrapper[funcName]() : wrapper.thru(func);
          }
        }
        return function() {
          var args = arguments;
          if (wrapper && args.length == 1 && isArray(args[0])) {
            return wrapper.plant(args[0]).value();
          }
          var index = 0,
              result = funcs[index].apply(this, args);

          while (++index < length) {
            result = funcs[index].call(this, result);
          }
          return result;
        };
      };
    }

    /**
     * Creates a function for `_.forEach` or `_.forEachRight`.
     *
     * @private
     * @param {Function} arrayFunc The function to iterate over an array.
     * @param {Function} eachFunc The function to iterate over a collection.
     * @returns {Function} Returns the new each function.
     */
    function createForEach(arrayFunc, eachFunc) {
      return function(collection, iteratee, thisArg) {
        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
          ? arrayFunc(collection, iteratee)
          : eachFunc(collection, bindCallback(iteratee, thisArg, 3));
      };
    }

    /**
     * Creates a function for `_.forIn` or `_.forInRight`.
     *
     * @private
     * @param {Function} objectFunc The function to iterate over an object.
     * @returns {Function} Returns the new each function.
     */
    function createForIn(objectFunc) {
      return function(object, iteratee, thisArg) {
        if (typeof iteratee != 'function' || thisArg !== undefined) {
          iteratee = bindCallback(iteratee, thisArg, 3);
        }
        return objectFunc(object, iteratee, keysIn);
      };
    }

    /**
     * Creates a function for `_.forOwn` or `_.forOwnRight`.
     *
     * @private
     * @param {Function} objectFunc The function to iterate over an object.
     * @returns {Function} Returns the new each function.
     */
    function createForOwn(objectFunc) {
      return function(object, iteratee, thisArg) {
        if (typeof iteratee != 'function' || thisArg !== undefined) {
          iteratee = bindCallback(iteratee, thisArg, 3);
        }
        return objectFunc(object, iteratee);
      };
    }

    /**
     * Creates a function for `_.padLeft` or `_.padRight`.
     *
     * @private
     * @param {boolean} [fromRight] Specify padding from the right.
     * @returns {Function} Returns the new pad function.
     */
    function createPadDir(fromRight) {
      return function(string, length, chars) {
        string = baseToString(string);
        return string && ((fromRight ? string : '') + createPadding(string, length, chars) + (fromRight ? '' : string));
      };
    }

    /**
     * Creates a `_.partial` or `_.partialRight` function.
     *
     * @private
     * @param {boolean} flag The partial bit flag.
     * @returns {Function} Returns the new partial function.
     */
    function createPartial(flag) {
      var partialFunc = restParam(function(func, partials) {
        var holders = replaceHolders(partials, partialFunc.placeholder);
        return createWrapper(func, flag, null, partials, holders);
      });
      return partialFunc;
    }

    /**
     * Creates a function for `_.reduce` or `_.reduceRight`.
     *
     * @private
     * @param {Function} arrayFunc The function to iterate over an array.
     * @param {Function} eachFunc The function to iterate over a collection.
     * @returns {Function} Returns the new each function.
     */
    function createReduce(arrayFunc, eachFunc) {
      return function(collection, iteratee, accumulator, thisArg) {
        var initFromArray = arguments.length < 3;
        return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
          ? arrayFunc(collection, iteratee, accumulator, initFromArray)
          : baseReduce(collection, getCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
      };
    }

    /**
     * Creates a function that wraps `func` and invokes it with optional `this`
     * binding of, partial application, and currying.
     *
     * @private
     * @param {Function|string} func The function or method name to reference.
     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {Array} [partials] The arguments to prepend to those provided to the new function.
     * @param {Array} [holders] The `partials` placeholder indexes.
     * @param {Array} [partialsRight] The arguments to append to those provided to the new function.
     * @param {Array} [holdersRight] The `partialsRight` placeholder indexes.
     * @param {Array} [argPos] The argument positions of the new function.
     * @param {number} [ary] The arity cap of `func`.
     * @param {number} [arity] The arity of `func`.
     * @returns {Function} Returns the new wrapped function.
     */
    function createHybridWrapper(func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity) {
      var isAry = bitmask & ARY_FLAG,
          isBind = bitmask & BIND_FLAG,
          isBindKey = bitmask & BIND_KEY_FLAG,
          isCurry = bitmask & CURRY_FLAG,
          isCurryBound = bitmask & CURRY_BOUND_FLAG,
          isCurryRight = bitmask & CURRY_RIGHT_FLAG;

      var Ctor = !isBindKey && createCtorWrapper(func),
          key = func;

      function wrapper() {
        // Avoid `arguments` object use disqualifying optimizations by
        // converting it to an array before providing it to other functions.
        var length = arguments.length,
            index = length,
            args = Array(length);

        while (index--) {
          args[index] = arguments[index];
        }
        if (partials) {
          args = composeArgs(args, partials, holders);
        }
        if (partialsRight) {
          args = composeArgsRight(args, partialsRight, holdersRight);
        }
        if (isCurry || isCurryRight) {
          var placeholder = wrapper.placeholder,
              argsHolders = replaceHolders(args, placeholder);

          length -= argsHolders.length;
          if (length < arity) {
            var newArgPos = argPos ? arrayCopy(argPos) : null,
                newArity = nativeMax(arity - length, 0),
                newsHolders = isCurry ? argsHolders : null,
                newHoldersRight = isCurry ? null : argsHolders,
                newPartials = isCurry ? args : null,
                newPartialsRight = isCurry ? null : args;

            bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
            bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);

            if (!isCurryBound) {
              bitmask &= ~(BIND_FLAG | BIND_KEY_FLAG);
            }
            var newData = [func, bitmask, thisArg, newPartials, newsHolders, newPartialsRight, newHoldersRight, newArgPos, ary, newArity],
                result = createHybridWrapper.apply(undefined, newData);

            if (isLaziable(func)) {
              setData(result, newData);
            }
            result.placeholder = placeholder;
            return result;
          }
        }
        var thisBinding = isBind ? thisArg : this;
        if (isBindKey) {
          func = thisBinding[key];
        }
        if (argPos) {
          args = reorder(args, argPos);
        }
        if (isAry && ary < args.length) {
          args.length = ary;
        }
        var fn = (this && this !== root && this instanceof wrapper) ? (Ctor || createCtorWrapper(func)) : func;
        return fn.apply(thisBinding, args);
      }
      return wrapper;
    }

    /**
     * Creates the padding required for `string` based on the given `length`.
     * The `chars` string is truncated if the number of characters exceeds `length`.
     *
     * @private
     * @param {string} string The string to create padding for.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the pad for `string`.
     */
    function createPadding(string, length, chars) {
      var strLength = string.length;
      length = +length;

      if (strLength >= length || !nativeIsFinite(length)) {
        return '';
      }
      var padLength = length - strLength;
      chars = chars == null ? ' ' : (chars + '');
      return repeat(chars, ceil(padLength / chars.length)).slice(0, padLength);
    }

    /**
     * Creates a function that wraps `func` and invokes it with the optional `this`
     * binding of `thisArg` and the `partials` prepended to those provided to
     * the wrapper.
     *
     * @private
     * @param {Function} func The function to partially apply arguments to.
     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
     * @param {*} thisArg The `this` binding of `func`.
     * @param {Array} partials The arguments to prepend to those provided to the new function.
     * @returns {Function} Returns the new bound function.
     */
    function createPartialWrapper(func, bitmask, thisArg, partials) {
      var isBind = bitmask & BIND_FLAG,
          Ctor = createCtorWrapper(func);

      function wrapper() {
        // Avoid `arguments` object use disqualifying optimizations by
        // converting it to an array before providing it `func`.
        var argsIndex = -1,
            argsLength = arguments.length,
            leftIndex = -1,
            leftLength = partials.length,
            args = Array(argsLength + leftLength);

        while (++leftIndex < leftLength) {
          args[leftIndex] = partials[leftIndex];
        }
        while (argsLength--) {
          args[leftIndex++] = arguments[++argsIndex];
        }
        var fn = (this && this !== root && this instanceof wrapper) ? Ctor : func;
        return fn.apply(isBind ? thisArg : this, args);
      }
      return wrapper;
    }

    /**
     * Creates a `_.sortedIndex` or `_.sortedLastIndex` function.
     *
     * @private
     * @param {boolean} [retHighest] Specify returning the highest qualified index.
     * @returns {Function} Returns the new index function.
     */
    function createSortedIndex(retHighest) {
      return function(array, value, iteratee, thisArg) {
        var func = getCallback(iteratee);
        return (func === baseCallback && iteratee == null)
          ? binaryIndex(array, value, retHighest)
          : binaryIndexBy(array, value, func(iteratee, thisArg, 1), retHighest);
      };
    }

    /**
     * Creates a function that either curries or invokes `func` with optional
     * `this` binding and partially applied arguments.
     *
     * @private
     * @param {Function|string} func The function or method name to reference.
     * @param {number} bitmask The bitmask of flags.
     *  The bitmask may be composed of the following flags:
     *     1 - `_.bind`
     *     2 - `_.bindKey`
     *     4 - `_.curry` or `_.curryRight` of a bound function
     *     8 - `_.curry`
     *    16 - `_.curryRight`
     *    32 - `_.partial`
     *    64 - `_.partialRight`
     *   128 - `_.rearg`
     *   256 - `_.ary`
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {Array} [partials] The arguments to be partially applied.
     * @param {Array} [holders] The `partials` placeholder indexes.
     * @param {Array} [argPos] The argument positions of the new function.
     * @param {number} [ary] The arity cap of `func`.
     * @param {number} [arity] The arity of `func`.
     * @returns {Function} Returns the new wrapped function.
     */
    function createWrapper(func, bitmask, thisArg, partials, holders, argPos, ary, arity) {
      var isBindKey = bitmask & BIND_KEY_FLAG;
      if (!isBindKey && typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var length = partials ? partials.length : 0;
      if (!length) {
        bitmask &= ~(PARTIAL_FLAG | PARTIAL_RIGHT_FLAG);
        partials = holders = null;
      }
      length -= (holders ? holders.length : 0);
      if (bitmask & PARTIAL_RIGHT_FLAG) {
        var partialsRight = partials,
            holdersRight = holders;

        partials = holders = null;
      }
      var data = isBindKey ? null : getData(func),
          newData = [func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity];

      if (data) {
        mergeData(newData, data);
        bitmask = newData[1];
        arity = newData[9];
      }
      newData[9] = arity == null
        ? (isBindKey ? 0 : func.length)
        : (nativeMax(arity - length, 0) || 0);

      if (bitmask == BIND_FLAG) {
        var result = createBindWrapper(newData[0], newData[2]);
      } else if ((bitmask == PARTIAL_FLAG || bitmask == (BIND_FLAG | PARTIAL_FLAG)) && !newData[4].length) {
        result = createPartialWrapper.apply(undefined, newData);
      } else {
        result = createHybridWrapper.apply(undefined, newData);
      }
      var setter = data ? baseSetData : setData;
      return setter(result, newData);
    }

    /**
     * A specialized version of `baseIsEqualDeep` for arrays with support for
     * partial deep comparisons.
     *
     * @private
     * @param {Array} array The array to compare.
     * @param {Array} other The other array to compare.
     * @param {Function} equalFunc The function to determine equivalents of values.
     * @param {Function} [customizer] The function to customize comparing arrays.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA] Tracks traversed `value` objects.
     * @param {Array} [stackB] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the arrays are equivalent, else `false`.
     */
    function equalArrays(array, other, equalFunc, customizer, isLoose, stackA, stackB) {
      var index = -1,
          arrLength = array.length,
          othLength = other.length,
          result = true;

      if (arrLength != othLength && !(isLoose && othLength > arrLength)) {
        return false;
      }
      // Deep compare the contents, ignoring non-numeric properties.
      while (result && ++index < arrLength) {
        var arrValue = array[index],
            othValue = other[index];

        result = undefined;
        if (customizer) {
          result = isLoose
            ? customizer(othValue, arrValue, index)
            : customizer(arrValue, othValue, index);
        }
        if (result === undefined) {
          // Recursively compare arrays (susceptible to call stack limits).
          if (isLoose) {
            var othIndex = othLength;
            while (othIndex--) {
              othValue = other[othIndex];
              result = (arrValue && arrValue === othValue) || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB);
              if (result) {
                break;
              }
            }
          } else {
            result = (arrValue && arrValue === othValue) || equalFunc(arrValue, othValue, customizer, isLoose, stackA, stackB);
          }
        }
      }
      return !!result;
    }

    /**
     * A specialized version of `baseIsEqualDeep` for comparing objects of
     * the same `toStringTag`.
     *
     * **Note:** This function only supports comparing values with tags of
     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
     *
     * @private
     * @param {Object} value The object to compare.
     * @param {Object} other The other object to compare.
     * @param {string} tag The `toStringTag` of the objects to compare.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function equalByTag(object, other, tag) {
      switch (tag) {
        case boolTag:
        case dateTag:
          // Coerce dates and booleans to numbers, dates to milliseconds and booleans
          // to `1` or `0` treating invalid dates coerced to `NaN` as not equal.
          return +object == +other;

        case errorTag:
          return object.name == other.name && object.message == other.message;

        case numberTag:
          // Treat `NaN` vs. `NaN` as equal.
          return (object != +object)
            ? other != +other
            // But, treat `-0` vs. `+0` as not equal.
            : (object == 0 ? ((1 / object) == (1 / other)) : object == +other);

        case regexpTag:
        case stringTag:
          // Coerce regexes to strings and treat strings primitives and string
          // objects as equal. See https://es5.github.io/#x15.10.6.4 for more details.
          return object == (other + '');
      }
      return false;
    }

    /**
     * A specialized version of `baseIsEqualDeep` for objects with support for
     * partial deep comparisons.
     *
     * @private
     * @param {Object} object The object to compare.
     * @param {Object} other The other object to compare.
     * @param {Function} equalFunc The function to determine equivalents of values.
     * @param {Function} [customizer] The function to customize comparing values.
     * @param {boolean} [isLoose] Specify performing partial comparisons.
     * @param {Array} [stackA] Tracks traversed `value` objects.
     * @param {Array} [stackB] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
     */
    function equalObjects(object, other, equalFunc, customizer, isLoose, stackA, stackB) {
      var objProps = keys(object),
          objLength = objProps.length,
          othProps = keys(other),
          othLength = othProps.length;

      if (objLength != othLength && !isLoose) {
        return false;
      }
      var skipCtor = isLoose,
          index = -1;

      while (++index < objLength) {
        var key = objProps[index],
            result = isLoose ? key in other : hasOwnProperty.call(other, key);

        if (result) {
          var objValue = object[key],
              othValue = other[key];

          result = undefined;
          if (customizer) {
            result = isLoose
              ? customizer(othValue, objValue, key)
              : customizer(objValue, othValue, key);
          }
          if (result === undefined) {
            // Recursively compare objects (susceptible to call stack limits).
            result = (objValue && objValue === othValue) || equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB);
          }
        }
        if (!result) {
          return false;
        }
        skipCtor || (skipCtor = key == 'constructor');
      }
      if (!skipCtor) {
        var objCtor = object.constructor,
            othCtor = other.constructor;

        // Non `Object` object instances with different constructors are not equal.
        if (objCtor != othCtor &&
            ('constructor' in object && 'constructor' in other) &&
            !(typeof objCtor == 'function' && objCtor instanceof objCtor &&
              typeof othCtor == 'function' && othCtor instanceof othCtor)) {
          return false;
        }
      }
      return true;
    }

    /**
     * Gets the extremum value of `collection` invoking `iteratee` for each value
     * in `collection` to generate the criterion by which the value is ranked.
     * The `iteratee` is invoked with three arguments: (value, index, collection).
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {boolean} [isMin] Specify returning the minimum, instead of the
     *  maximum, extremum value.
     * @returns {*} Returns the extremum value.
     */
    function extremumBy(collection, iteratee, isMin) {
      var exValue = isMin ? POSITIVE_INFINITY : NEGATIVE_INFINITY,
          computed = exValue,
          result = computed;

      baseEach(collection, function(value, index, collection) {
        var current = iteratee(value, index, collection);
        if ((isMin ? (current < computed) : (current > computed)) ||
            (current === exValue && current === result)) {
          computed = current;
          result = value;
        }
      });
      return result;
    }

    /**
     * Gets the appropriate "callback" function. If the `_.callback` method is
     * customized this function returns the custom method, otherwise it returns
     * the `baseCallback` function. If arguments are provided the chosen function
     * is invoked with them and its result is returned.
     *
     * @private
     * @returns {Function} Returns the chosen function or its result.
     */
    function getCallback(func, thisArg, argCount) {
      var result = lodash.callback || callback;
      result = result === callback ? baseCallback : result;
      return argCount ? result(func, thisArg, argCount) : result;
    }

    /**
     * Gets metadata for `func`.
     *
     * @private
     * @param {Function} func The function to query.
     * @returns {*} Returns the metadata for `func`.
     */
    var getData = !metaMap ? noop : function(func) {
      return metaMap.get(func);
    };

    /**
     * Gets the name of `func`.
     *
     * @private
     * @param {Function} func The function to query.
     * @returns {string} Returns the function name.
     */
    var getFuncName = (function() {
      if (!support.funcNames) {
        return constant('');
      }
      if (constant.name == 'constant') {
        return baseProperty('name');
      }
      return function(func) {
        var result = func.name,
            array = realNames[result],
            length = array ? array.length : 0;

        while (length--) {
          var data = array[length],
              otherFunc = data.func;

          if (otherFunc == null || otherFunc == func) {
            return data.name;
          }
        }
        return result;
      };
    }());

    /**
     * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
     * customized this function returns the custom method, otherwise it returns
     * the `baseIndexOf` function. If arguments are provided the chosen function
     * is invoked with them and its result is returned.
     *
     * @private
     * @returns {Function|number} Returns the chosen function or its result.
     */
    function getIndexOf(collection, target, fromIndex) {
      var result = lodash.indexOf || indexOf;
      result = result === indexOf ? baseIndexOf : result;
      return collection ? result(collection, target, fromIndex) : result;
    }

    /**
     * Gets the "length" property value of `object`.
     *
     * **Note:** This function is used to avoid a [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792)
     * in Safari on iOS 8.1 ARM64.
     *
     * @private
     * @param {Object} object The object to query.
     * @returns {*} Returns the "length" value.
     */
    var getLength = baseProperty('length');

    /**
     * Creates an array of the own symbols of `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of symbols.
     */
    var getSymbols = !getOwnPropertySymbols ? constant([]) : function(object) {
      return getOwnPropertySymbols(toObject(object));
    };

    /**
     * Gets the view, applying any `transforms` to the `start` and `end` positions.
     *
     * @private
     * @param {number} start The start of the view.
     * @param {number} end The end of the view.
     * @param {Array} [transforms] The transformations to apply to the view.
     * @returns {Object} Returns an object containing the `start` and `end`
     *  positions of the view.
     */
    function getView(start, end, transforms) {
      var index = -1,
          length = transforms ? transforms.length : 0;

      while (++index < length) {
        var data = transforms[index],
            size = data.size;

        switch (data.type) {
          case 'drop':      start += size; break;
          case 'dropRight': end -= size; break;
          case 'take':      end = nativeMin(end, start + size); break;
          case 'takeRight': start = nativeMax(start, end - size); break;
        }
      }
      return { 'start': start, 'end': end };
    }

    /**
     * Initializes an array clone.
     *
     * @private
     * @param {Array} array The array to clone.
     * @returns {Array} Returns the initialized clone.
     */
    function initCloneArray(array) {
      var length = array.length,
          result = new array.constructor(length);

      // Add array properties assigned by `RegExp#exec`.
      if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
        result.index = array.index;
        result.input = array.input;
      }
      return result;
    }

    /**
     * Initializes an object clone.
     *
     * @private
     * @param {Object} object The object to clone.
     * @returns {Object} Returns the initialized clone.
     */
    function initCloneObject(object) {
      var Ctor = object.constructor;
      if (!(typeof Ctor == 'function' && Ctor instanceof Ctor)) {
        Ctor = Object;
      }
      return new Ctor;
    }

    /**
     * Initializes an object clone based on its `toStringTag`.
     *
     * **Note:** This function only supports cloning values with tags of
     * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
     *
     * @private
     * @param {Object} object The object to clone.
     * @param {string} tag The `toStringTag` of the object to clone.
     * @param {boolean} [isDeep] Specify a deep clone.
     * @returns {Object} Returns the initialized clone.
     */
    function initCloneByTag(object, tag, isDeep) {
      var Ctor = object.constructor;
      switch (tag) {
        case arrayBufferTag:
          return bufferClone(object);

        case boolTag:
        case dateTag:
          return new Ctor(+object);

        case float32Tag: case float64Tag:
        case int8Tag: case int16Tag: case int32Tag:
        case uint8Tag: case uint8ClampedTag: case uint16Tag: case uint32Tag:
          var buffer = object.buffer;
          return new Ctor(isDeep ? bufferClone(buffer) : buffer, object.byteOffset, object.length);

        case numberTag:
        case stringTag:
          return new Ctor(object);

        case regexpTag:
          var result = new Ctor(object.source, reFlags.exec(object));
          result.lastIndex = object.lastIndex;
      }
      return result;
    }

    /**
     * Invokes the method at `path` on `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @param {Array|string} path The path of the method to invoke.
     * @param {Array} args The arguments to invoke the method with.
     * @returns {*} Returns the result of the invoked method.
     */
    function invokePath(object, path, args) {
      if (object != null && !isKey(path, object)) {
        path = toPath(path);
        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
        path = last(path);
      }
      var func = object == null ? object : object[path];
      return func == null ? undefined : func.apply(object, args);
    }

    /**
     * Checks if `value` is a valid array-like index.
     *
     * @private
     * @param {*} value The value to check.
     * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
     * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
     */
    function isIndex(value, length) {
      value = +value;
      length = length == null ? MAX_SAFE_INTEGER : length;
      return value > -1 && value % 1 == 0 && value < length;
    }

    /**
     * Checks if the provided arguments are from an iteratee call.
     *
     * @private
     * @param {*} value The potential iteratee value argument.
     * @param {*} index The potential iteratee index or key argument.
     * @param {*} object The potential iteratee object argument.
     * @returns {boolean} Returns `true` if the arguments are from an iteratee call, else `false`.
     */
    function isIterateeCall(value, index, object) {
      if (!isObject(object)) {
        return false;
      }
      var type = typeof index;
      if (type == 'number') {
        var length = getLength(object),
            prereq = isLength(length) && isIndex(index, length);
      } else {
        prereq = type == 'string' && index in object;
      }
      if (prereq) {
        var other = object[index];
        return value === value ? (value === other) : (other !== other);
      }
      return false;
    }

    /**
     * Checks if `value` is a property name and not a property path.
     *
     * @private
     * @param {*} value The value to check.
     * @param {Object} [object] The object to query keys on.
     * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
     */
    function isKey(value, object) {
      var type = typeof value;
      if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
        return true;
      }
      if (isArray(value)) {
        return false;
      }
      var result = !reIsDeepProp.test(value);
      return result || (object != null && value in toObject(object));
    }

    /**
     * Checks if `func` has a lazy counterpart.
     *
     * @private
     * @param {Function} func The function to check.
     * @returns {boolean} Returns `true` if `func` has a lazy counterpart, else `false`.
     */
    function isLaziable(func) {
      var funcName = getFuncName(func);
      return !!funcName && func === lodash[funcName] && funcName in LazyWrapper.prototype;
    }

    /**
     * Checks if `value` is a valid array-like length.
     *
     * **Note:** This function is based on [`ToLength`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength).
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a valid length, else `false`.
     */
    function isLength(value) {
      return typeof value == 'number' && value > -1 && value % 1 == 0 && value <= MAX_SAFE_INTEGER;
    }

    /**
     * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` if suitable for strict
     *  equality comparisons, else `false`.
     */
    function isStrictComparable(value) {
      return value === value && (value === 0 ? ((1 / value) > 0) : !isObject(value));
    }

    /**
     * Merges the function metadata of `source` into `data`.
     *
     * Merging metadata reduces the number of wrappers required to invoke a function.
     * This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
     * may be applied regardless of execution order. Methods like `_.ary` and `_.rearg`
     * augment function arguments, making the order in which they are executed important,
     * preventing the merging of metadata. However, we make an exception for a safe
     * common case where curried functions have `_.ary` and or `_.rearg` applied.
     *
     * @private
     * @param {Array} data The destination metadata.
     * @param {Array} source The source metadata.
     * @returns {Array} Returns `data`.
     */
    function mergeData(data, source) {
      var bitmask = data[1],
          srcBitmask = source[1],
          newBitmask = bitmask | srcBitmask,
          isCommon = newBitmask < ARY_FLAG;

      var isCombo =
        (srcBitmask == ARY_FLAG && bitmask == CURRY_FLAG) ||
        (srcBitmask == ARY_FLAG && bitmask == REARG_FLAG && data[7].length <= source[8]) ||
        (srcBitmask == (ARY_FLAG | REARG_FLAG) && bitmask == CURRY_FLAG);

      // Exit early if metadata can't be merged.
      if (!(isCommon || isCombo)) {
        return data;
      }
      // Use source `thisArg` if available.
      if (srcBitmask & BIND_FLAG) {
        data[2] = source[2];
        // Set when currying a bound function.
        newBitmask |= (bitmask & BIND_FLAG) ? 0 : CURRY_BOUND_FLAG;
      }
      // Compose partial arguments.
      var value = source[3];
      if (value) {
        var partials = data[3];
        data[3] = partials ? composeArgs(partials, value, source[4]) : arrayCopy(value);
        data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : arrayCopy(source[4]);
      }
      // Compose partial right arguments.
      value = source[5];
      if (value) {
        partials = data[5];
        data[5] = partials ? composeArgsRight(partials, value, source[6]) : arrayCopy(value);
        data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : arrayCopy(source[6]);
      }
      // Use source `argPos` if available.
      value = source[7];
      if (value) {
        data[7] = arrayCopy(value);
      }
      // Use source `ary` if it's smaller.
      if (srcBitmask & ARY_FLAG) {
        data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
      }
      // Use source `arity` if one is not provided.
      if (data[9] == null) {
        data[9] = source[9];
      }
      // Use source `func` and merge bitmasks.
      data[0] = source[0];
      data[1] = newBitmask;

      return data;
    }

    /**
     * A specialized version of `_.pick` that picks `object` properties specified
     * by `props`.
     *
     * @private
     * @param {Object} object The source object.
     * @param {string[]} props The property names to pick.
     * @returns {Object} Returns the new object.
     */
    function pickByArray(object, props) {
      object = toObject(object);

      var index = -1,
          length = props.length,
          result = {};

      while (++index < length) {
        var key = props[index];
        if (key in object) {
          result[key] = object[key];
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.pick` that picks `object` properties `predicate`
     * returns truthy for.
     *
     * @private
     * @param {Object} object The source object.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Object} Returns the new object.
     */
    function pickByCallback(object, predicate) {
      var result = {};
      baseForIn(object, function(value, key, object) {
        if (predicate(value, key, object)) {
          result[key] = value;
        }
      });
      return result;
    }

    /**
     * Reorder `array` according to the specified indexes where the element at
     * the first index is assigned as the first element, the element at
     * the second index is assigned as the second element, and so on.
     *
     * @private
     * @param {Array} array The array to reorder.
     * @param {Array} indexes The arranged array indexes.
     * @returns {Array} Returns `array`.
     */
    function reorder(array, indexes) {
      var arrLength = array.length,
          length = nativeMin(indexes.length, arrLength),
          oldArray = arrayCopy(array);

      while (length--) {
        var index = indexes[length];
        array[length] = isIndex(index, arrLength) ? oldArray[index] : undefined;
      }
      return array;
    }

    /**
     * Sets metadata for `func`.
     *
     * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
     * period of time, it will trip its breaker and transition to an identity function
     * to avoid garbage collection pauses in V8. See [V8 issue 2070](https://code.google.com/p/v8/issues/detail?id=2070)
     * for more details.
     *
     * @private
     * @param {Function} func The function to associate metadata with.
     * @param {*} data The metadata.
     * @returns {Function} Returns `func`.
     */
    var setData = (function() {
      var count = 0,
          lastCalled = 0;

      return function(key, value) {
        var stamp = now(),
            remaining = HOT_SPAN - (stamp - lastCalled);

        lastCalled = stamp;
        if (remaining > 0) {
          if (++count >= HOT_COUNT) {
            return key;
          }
        } else {
          count = 0;
        }
        return baseSetData(key, value);
      };
    }());

    /**
     * A fallback implementation of `_.isPlainObject` which checks if `value`
     * is an object created by the `Object` constructor or has a `[[Prototype]]`
     * of `null`.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
     */
    function shimIsPlainObject(value) {
      var Ctor,
          support = lodash.support;

      // Exit early for non `Object` objects.
      if (!(isObjectLike(value) && objToString.call(value) == objectTag) ||
          (!hasOwnProperty.call(value, 'constructor') &&
            (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
        return false;
      }
      // IE < 9 iterates inherited properties before own properties. If the first
      // iterated property is an object's own property then there are no inherited
      // enumerable properties.
      var result;
      // In most environments an object's own properties are iterated before
      // its inherited properties. If the last iterated property is an object's
      // own property then there are no inherited enumerable properties.
      baseForIn(value, function(subValue, key) {
        result = key;
      });
      return result === undefined || hasOwnProperty.call(value, result);
    }

    /**
     * A fallback implementation of `Object.keys` which creates an array of the
     * own enumerable property names of `object`.
     *
     * @private
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property names.
     */
    function shimKeys(object) {
      var props = keysIn(object),
          propsLength = props.length,
          length = propsLength && object.length,
          support = lodash.support;

      var allowIndexes = length && isLength(length) &&
        (isArray(object) || (support.nonEnumArgs && isArguments(object)));

      var index = -1,
          result = [];

      while (++index < propsLength) {
        var key = props[index];
        if ((allowIndexes && isIndex(key, length)) || hasOwnProperty.call(object, key)) {
          result.push(key);
        }
      }
      return result;
    }

    /**
     * Converts `value` to an array-like object if it is not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Array|Object} Returns the array-like object.
     */
    function toIterable(value) {
      if (value == null) {
        return [];
      }
      if (!isLength(getLength(value))) {
        return values(value);
      }
      return isObject(value) ? value : Object(value);
    }

    /**
     * Converts `value` to an object if it is not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Object} Returns the object.
     */
    function toObject(value) {
      return isObject(value) ? value : Object(value);
    }

    /**
     * Converts `value` to property path array if it is not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Array} Returns the property path array.
     */
    function toPath(value) {
      if (isArray(value)) {
        return value;
      }
      var result = [];
      baseToString(value).replace(rePropName, function(match, number, quote, string) {
        result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
      });
      return result;
    }

    /**
     * Creates a clone of `wrapper`.
     *
     * @private
     * @param {Object} wrapper The wrapper to clone.
     * @returns {Object} Returns the cloned wrapper.
     */
    function wrapperClone(wrapper) {
      return wrapper instanceof LazyWrapper
        ? wrapper.clone()
        : new LodashWrapper(wrapper.__wrapped__, wrapper.__chain__, arrayCopy(wrapper.__actions__));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates an array of elements split into groups the length of `size`.
     * If `collection` can't be split evenly, the final chunk will be the remaining
     * elements.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to process.
     * @param {number} [size=1] The length of each chunk.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the new array containing chunks.
     * @example
     *
     * _.chunk(['a', 'b', 'c', 'd'], 2);
     * // => [['a', 'b'], ['c', 'd']]
     *
     * _.chunk(['a', 'b', 'c', 'd'], 3);
     * // => [['a', 'b', 'c'], ['d']]
     */
    function chunk(array, size, guard) {
      if (guard ? isIterateeCall(array, size, guard) : size == null) {
        size = 1;
      } else {
        size = nativeMax(+size || 1, 1);
      }
      var index = 0,
          length = array ? array.length : 0,
          resIndex = -1,
          result = Array(ceil(length / size));

      while (index < length) {
        result[++resIndex] = baseSlice(array, index, (index += size));
      }
      return result;
    }

    /**
     * Creates an array with all falsey values removed. The values `false`, `null`,
     * `0`, `""`, `undefined`, and `NaN` are falsey.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to compact.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.compact([0, 1, false, 2, '', 3]);
     * // => [1, 2, 3]
     */
    function compact(array) {
      var index = -1,
          length = array ? array.length : 0,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];
        if (value) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * Creates an array excluding all values of the provided arrays using
     * `SameValueZero` for equality comparisons.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {...Array} [values] The arrays of values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.difference([1, 2, 3], [4, 2]);
     * // => [1, 3]
     */
    var difference = restParam(function(array, values) {
      return (isArray(array) || isArguments(array))
        ? baseDifference(array, baseFlatten(values, false, true))
        : [];
    });

    /**
     * Creates a slice of `array` with `n` elements dropped from the beginning.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to drop.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.drop([1, 2, 3]);
     * // => [2, 3]
     *
     * _.drop([1, 2, 3], 2);
     * // => [3]
     *
     * _.drop([1, 2, 3], 5);
     * // => []
     *
     * _.drop([1, 2, 3], 0);
     * // => [1, 2, 3]
     */
    function drop(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      return baseSlice(array, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with `n` elements dropped from the end.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to drop.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropRight([1, 2, 3]);
     * // => [1, 2]
     *
     * _.dropRight([1, 2, 3], 2);
     * // => [1]
     *
     * _.dropRight([1, 2, 3], 5);
     * // => []
     *
     * _.dropRight([1, 2, 3], 0);
     * // => [1, 2, 3]
     */
    function dropRight(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      n = length - (+n || 0);
      return baseSlice(array, 0, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` excluding elements dropped from the end.
     * Elements are dropped until `predicate` returns falsey. The predicate is
     * bound to `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that match the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropRightWhile([1, 2, 3], function(n) {
     *   return n > 1;
     * });
     * // => [1]
     *
     * var users = [
     *   { 'user': 'barney',  'active': true },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.dropRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
     * // => ['barney', 'fred']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.dropRightWhile(users, 'active', false), 'user');
     * // => ['barney']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.dropRightWhile(users, 'active'), 'user');
     * // => ['barney', 'fred', 'pebbles']
     */
    function dropRightWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3), true, true)
        : [];
    }

    /**
     * Creates a slice of `array` excluding elements dropped from the beginning.
     * Elements are dropped until `predicate` returns falsey. The predicate is
     * bound to `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropWhile([1, 2, 3], function(n) {
     *   return n < 3;
     * });
     * // => [3]
     *
     * var users = [
     *   { 'user': 'barney',  'active': false },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': true }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.dropWhile(users, { 'user': 'barney', 'active': false }), 'user');
     * // => ['fred', 'pebbles']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.dropWhile(users, 'active', false), 'user');
     * // => ['pebbles']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.dropWhile(users, 'active'), 'user');
     * // => ['barney', 'fred', 'pebbles']
     */
    function dropWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3), true)
        : [];
    }

    /**
     * Fills elements of `array` with `value` from `start` up to, but not
     * including, `end`.
     *
     * **Note:** This method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to fill.
     * @param {*} value The value to fill `array` with.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns `array`.
     * @example
     *
     * var array = [1, 2, 3];
     *
     * _.fill(array, 'a');
     * console.log(array);
     * // => ['a', 'a', 'a']
     *
     * _.fill(Array(3), 2);
     * // => [2, 2, 2]
     *
     * _.fill([4, 6, 8], '*', 1, 2);
     * // => [4, '*', 8]
     */
    function fill(array, value, start, end) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (start && typeof start != 'number' && isIterateeCall(array, value, start)) {
        start = 0;
        end = length;
      }
      return baseFill(array, value, start, end);
    }

    /**
     * This method is like `_.find` except that it returns the index of the first
     * element `predicate` returns truthy for instead of the element itself.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {number} Returns the index of the found element, else `-1`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'active': false },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': true }
     * ];
     *
     * _.findIndex(users, function(chr) {
     *   return chr.user == 'barney';
     * });
     * // => 0
     *
     * // using the `_.matches` callback shorthand
     * _.findIndex(users, { 'user': 'fred', 'active': false });
     * // => 1
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findIndex(users, 'active', false);
     * // => 0
     *
     * // using the `_.property` callback shorthand
     * _.findIndex(users, 'active');
     * // => 2
     */
    var findIndex = createFindIndex();

    /**
     * This method is like `_.findIndex` except that it iterates over elements
     * of `collection` from right to left.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {number} Returns the index of the found element, else `-1`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'active': true },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': false }
     * ];
     *
     * _.findLastIndex(users, function(chr) {
     *   return chr.user == 'pebbles';
     * });
     * // => 2
     *
     * // using the `_.matches` callback shorthand
     * _.findLastIndex(users, { 'user': 'barney', 'active': true });
     * // => 0
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findLastIndex(users, 'active', false);
     * // => 2
     *
     * // using the `_.property` callback shorthand
     * _.findLastIndex(users, 'active');
     * // => 0
     */
    var findLastIndex = createFindIndex(true);

    /**
     * Gets the first element of `array`.
     *
     * @static
     * @memberOf _
     * @alias head
     * @category Array
     * @param {Array} array The array to query.
     * @returns {*} Returns the first element of `array`.
     * @example
     *
     * _.first([1, 2, 3]);
     * // => 1
     *
     * _.first([]);
     * // => undefined
     */
    function first(array) {
      return array ? array[0] : undefined;
    }

    /**
     * Flattens a nested array. If `isDeep` is `true` the array is recursively
     * flattened, otherwise it is only flattened a single level.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to flatten.
     * @param {boolean} [isDeep] Specify a deep flatten.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the new flattened array.
     * @example
     *
     * _.flatten([1, [2, 3, [4]]]);
     * // => [1, 2, 3, [4]]
     *
     * // using `isDeep`
     * _.flatten([1, [2, 3, [4]]], true);
     * // => [1, 2, 3, 4]
     */
    function flatten(array, isDeep, guard) {
      var length = array ? array.length : 0;
      if (guard && isIterateeCall(array, isDeep, guard)) {
        isDeep = false;
      }
      return length ? baseFlatten(array, isDeep) : [];
    }

    /**
     * Recursively flattens a nested array.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to recursively flatten.
     * @returns {Array} Returns the new flattened array.
     * @example
     *
     * _.flattenDeep([1, [2, 3, [4]]]);
     * // => [1, 2, 3, 4]
     */
    function flattenDeep(array) {
      var length = array ? array.length : 0;
      return length ? baseFlatten(array, true) : [];
    }

    /**
     * Gets the index at which the first occurrence of `value` is found in `array`
     * using `SameValueZero` for equality comparisons. If `fromIndex` is negative,
     * it is used as the offset from the end of `array`. If `array` is sorted
     * providing `true` for `fromIndex` performs a faster binary search.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {*} value The value to search for.
     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
     *  to perform a binary search on a sorted array.
     * @returns {number} Returns the index of the matched value, else `-1`.
     * @example
     *
     * _.indexOf([1, 2, 1, 2], 2);
     * // => 1
     *
     * // using `fromIndex`
     * _.indexOf([1, 2, 1, 2], 2, 2);
     * // => 3
     *
     * // performing a binary search
     * _.indexOf([1, 1, 2, 2], 2, true);
     * // => 2
     */
    function indexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (!length) {
        return -1;
      }
      if (typeof fromIndex == 'number') {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
      } else if (fromIndex) {
        var index = binaryIndex(array, value),
            other = array[index];

        if (value === value ? (value === other) : (other !== other)) {
          return index;
        }
        return -1;
      }
      return baseIndexOf(array, value, fromIndex || 0);
    }

    /**
     * Gets all but the last element of `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.initial([1, 2, 3]);
     * // => [1, 2]
     */
    function initial(array) {
      return dropRight(array, 1);
    }

    /**
     * Creates an array of unique values in all provided arrays using `SameValueZero`
     * for equality comparisons.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of shared values.
     * @example
     * _.intersection([1, 2], [4, 2], [2, 1]);
     * // => [2]
     */
    function intersection() {
      var args = [],
          argsIndex = -1,
          argsLength = arguments.length,
          caches = [],
          indexOf = getIndexOf(),
          isCommon = indexOf == baseIndexOf,
          result = [];

      while (++argsIndex < argsLength) {
        var value = arguments[argsIndex];
        if (isArray(value) || isArguments(value)) {
          args.push(value);
          caches.push((isCommon && value.length >= 120) ? createCache(argsIndex && value) : null);
        }
      }
      argsLength = args.length;
      if (argsLength < 2) {
        return result;
      }
      var array = args[0],
          index = -1,
          length = array ? array.length : 0,
          seen = caches[0];

      outer:
      while (++index < length) {
        value = array[index];
        if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
          argsIndex = argsLength;
          while (--argsIndex) {
            var cache = caches[argsIndex];
            if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value, 0)) < 0) {
              continue outer;
            }
          }
          if (seen) {
            seen.push(value);
          }
          result.push(value);
        }
      }
      return result;
    }

    /**
     * Gets the last element of `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @returns {*} Returns the last element of `array`.
     * @example
     *
     * _.last([1, 2, 3]);
     * // => 3
     */
    function last(array) {
      var length = array ? array.length : 0;
      return length ? array[length - 1] : undefined;
    }

    /**
     * This method is like `_.indexOf` except that it iterates over elements of
     * `array` from right to left.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {*} value The value to search for.
     * @param {boolean|number} [fromIndex=array.length-1] The index to search from
     *  or `true` to perform a binary search on a sorted array.
     * @returns {number} Returns the index of the matched value, else `-1`.
     * @example
     *
     * _.lastIndexOf([1, 2, 1, 2], 2);
     * // => 3
     *
     * // using `fromIndex`
     * _.lastIndexOf([1, 2, 1, 2], 2, 2);
     * // => 1
     *
     * // performing a binary search
     * _.lastIndexOf([1, 1, 2, 2], 2, true);
     * // => 3
     */
    function lastIndexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (!length) {
        return -1;
      }
      var index = length;
      if (typeof fromIndex == 'number') {
        index = (fromIndex < 0 ? nativeMax(length + fromIndex, 0) : nativeMin(fromIndex || 0, length - 1)) + 1;
      } else if (fromIndex) {
        index = binaryIndex(array, value, true) - 1;
        var other = array[index];
        if (value === value ? (value === other) : (other !== other)) {
          return index;
        }
        return -1;
      }
      if (value !== value) {
        return indexOfNaN(array, index, true);
      }
      while (index--) {
        if (array[index] === value) {
          return index;
        }
      }
      return -1;
    }

    /**
     * Removes all provided values from `array` using `SameValueZero` for equality
     * comparisons.
     *
     * **Notes:**
     *  - Unlike `_.without`, this method mutates `array`
     *  - [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     *    comparisons are like strict equality comparisons, e.g. `===`, except
     *    that `NaN` matches `NaN`
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {...*} [values] The values to remove.
     * @returns {Array} Returns `array`.
     * @example
     *
     * var array = [1, 2, 3, 1, 2, 3];
     *
     * _.pull(array, 2, 3);
     * console.log(array);
     * // => [1, 1]
     */
    function pull() {
      var args = arguments,
          array = args[0];

      if (!(array && array.length)) {
        return array;
      }
      var index = 0,
          indexOf = getIndexOf(),
          length = args.length;

      while (++index < length) {
        var fromIndex = 0,
            value = args[index];

        while ((fromIndex = indexOf(array, value, fromIndex)) > -1) {
          splice.call(array, fromIndex, 1);
        }
      }
      return array;
    }

    /**
     * Removes elements from `array` corresponding to the given indexes and returns
     * an array of the removed elements. Indexes may be specified as an array of
     * indexes or as individual arguments.
     *
     * **Note:** Unlike `_.at`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {...(number|number[])} [indexes] The indexes of elements to remove,
     *  specified as individual indexes or arrays of indexes.
     * @returns {Array} Returns the new array of removed elements.
     * @example
     *
     * var array = [5, 10, 15, 20];
     * var evens = _.pullAt(array, 1, 3);
     *
     * console.log(array);
     * // => [5, 15]
     *
     * console.log(evens);
     * // => [10, 20]
     */
    var pullAt = restParam(function(array, indexes) {
      array || (array = []);
      indexes = baseFlatten(indexes);

      var result = baseAt(array, indexes);
      basePullAt(array, indexes.sort(baseCompareAscending));
      return result;
    });

    /**
     * Removes all elements from `array` that `predicate` returns truthy for
     * and returns an array of the removed elements. The predicate is bound to
     * `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * **Note:** Unlike `_.filter`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new array of removed elements.
     * @example
     *
     * var array = [1, 2, 3, 4];
     * var evens = _.remove(array, function(n) {
     *   return n % 2 == 0;
     * });
     *
     * console.log(array);
     * // => [1, 3]
     *
     * console.log(evens);
     * // => [2, 4]
     */
    function remove(array, predicate, thisArg) {
      var result = [];
      if (!(array && array.length)) {
        return result;
      }
      var index = -1,
          indexes = [],
          length = array.length;

      predicate = getCallback(predicate, thisArg, 3);
      while (++index < length) {
        var value = array[index];
        if (predicate(value, index, array)) {
          result.push(value);
          indexes.push(index);
        }
      }
      basePullAt(array, indexes);
      return result;
    }

    /**
     * Gets all but the first element of `array`.
     *
     * @static
     * @memberOf _
     * @alias tail
     * @category Array
     * @param {Array} array The array to query.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.rest([1, 2, 3]);
     * // => [2, 3]
     */
    function rest(array) {
      return drop(array, 1);
    }

    /**
     * Creates a slice of `array` from `start` up to, but not including, `end`.
     *
     * **Note:** This method is used instead of `Array#slice` to support node
     * lists in IE < 9 and to ensure dense arrays are returned.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to slice.
     * @param {number} [start=0] The start position.
     * @param {number} [end=array.length] The end position.
     * @returns {Array} Returns the slice of `array`.
     */
    function slice(array, start, end) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (end && typeof end != 'number' && isIterateeCall(array, start, end)) {
        start = 0;
        end = length;
      }
      return baseSlice(array, start, end);
    }

    /**
     * Uses a binary search to determine the lowest index at which `value` should
     * be inserted into `array` in order to maintain its sort order. If an iteratee
     * function is provided it is invoked for `value` and each element of `array`
     * to compute their sort ranking. The iteratee is bound to `thisArg` and
     * invoked with one argument; (value).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     * @example
     *
     * _.sortedIndex([30, 50], 40);
     * // => 1
     *
     * _.sortedIndex([4, 4, 5, 5], 5);
     * // => 2
     *
     * var dict = { 'data': { 'thirty': 30, 'forty': 40, 'fifty': 50 } };
     *
     * // using an iteratee function
     * _.sortedIndex(['thirty', 'fifty'], 'forty', function(word) {
     *   return this.data[word];
     * }, dict);
     * // => 1
     *
     * // using the `_.property` callback shorthand
     * _.sortedIndex([{ 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
     * // => 1
     */
    var sortedIndex = createSortedIndex();

    /**
     * This method is like `_.sortedIndex` except that it returns the highest
     * index at which `value` should be inserted into `array` in order to
     * maintain its sort order.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The sorted array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     * @example
     *
     * _.sortedLastIndex([4, 4, 5, 5], 5);
     * // => 4
     */
    var sortedLastIndex = createSortedIndex(true);

    /**
     * Creates a slice of `array` with `n` elements taken from the beginning.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to take.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.take([1, 2, 3]);
     * // => [1]
     *
     * _.take([1, 2, 3], 2);
     * // => [1, 2]
     *
     * _.take([1, 2, 3], 5);
     * // => [1, 2, 3]
     *
     * _.take([1, 2, 3], 0);
     * // => []
     */
    function take(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      return baseSlice(array, 0, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with `n` elements taken from the end.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to take.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeRight([1, 2, 3]);
     * // => [3]
     *
     * _.takeRight([1, 2, 3], 2);
     * // => [2, 3]
     *
     * _.takeRight([1, 2, 3], 5);
     * // => [1, 2, 3]
     *
     * _.takeRight([1, 2, 3], 0);
     * // => []
     */
    function takeRight(array, n, guard) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (guard ? isIterateeCall(array, n, guard) : n == null) {
        n = 1;
      }
      n = length - (+n || 0);
      return baseSlice(array, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with elements taken from the end. Elements are
     * taken until `predicate` returns falsey. The predicate is bound to `thisArg`
     * and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeRightWhile([1, 2, 3], function(n) {
     *   return n > 1;
     * });
     * // => [2, 3]
     *
     * var users = [
     *   { 'user': 'barney',  'active': true },
     *   { 'user': 'fred',    'active': false },
     *   { 'user': 'pebbles', 'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.takeRightWhile(users, { 'user': 'pebbles', 'active': false }), 'user');
     * // => ['pebbles']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.takeRightWhile(users, 'active', false), 'user');
     * // => ['fred', 'pebbles']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.takeRightWhile(users, 'active'), 'user');
     * // => []
     */
    function takeRightWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3), false, true)
        : [];
    }

    /**
     * Creates a slice of `array` with elements taken from the beginning. Elements
     * are taken until `predicate` returns falsey. The predicate is bound to
     * `thisArg` and invoked with three arguments: (value, index, array).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeWhile([1, 2, 3], function(n) {
     *   return n < 3;
     * });
     * // => [1, 2]
     *
     * var users = [
     *   { 'user': 'barney',  'active': false },
     *   { 'user': 'fred',    'active': false},
     *   { 'user': 'pebbles', 'active': true }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.takeWhile(users, { 'user': 'barney', 'active': false }), 'user');
     * // => ['barney']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.takeWhile(users, 'active', false), 'user');
     * // => ['barney', 'fred']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.takeWhile(users, 'active'), 'user');
     * // => []
     */
    function takeWhile(array, predicate, thisArg) {
      return (array && array.length)
        ? baseWhile(array, getCallback(predicate, thisArg, 3))
        : [];
    }

    /**
     * Creates an array of unique values, in order, of the provided arrays using
     * `SameValueZero` for equality comparisons.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of combined values.
     * @example
     *
     * _.union([1, 2], [4, 2], [2, 1]);
     * // => [1, 2, 4]
     */
    var union = restParam(function(arrays) {
      return baseUniq(baseFlatten(arrays, false, true));
    });

    /**
     * Creates a duplicate-free version of an array, using `SameValueZero` for
     * equality comparisons, in which only the first occurence of each element
     * is kept. Providing `true` for `isSorted` performs a faster search algorithm
     * for sorted arrays. If an iteratee function is provided it is invoked for
     * each element in the array to generate the criterion by which uniqueness
     * is computed. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index, array).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @alias unique
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {boolean} [isSorted] Specify the array is sorted.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new duplicate-value-free array.
     * @example
     *
     * _.uniq([2, 1, 2]);
     * // => [2, 1]
     *
     * // using `isSorted`
     * _.uniq([1, 1, 2], true);
     * // => [1, 2]
     *
     * // using an iteratee function
     * _.uniq([1, 2.5, 1.5, 2], function(n) {
     *   return this.floor(n);
     * }, Math);
     * // => [1, 2.5]
     *
     * // using the `_.property` callback shorthand
     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
     * // => [{ 'x': 1 }, { 'x': 2 }]
     */
    function uniq(array, isSorted, iteratee, thisArg) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      if (isSorted != null && typeof isSorted != 'boolean') {
        thisArg = iteratee;
        iteratee = isIterateeCall(array, isSorted, thisArg) ? null : isSorted;
        isSorted = false;
      }
      var func = getCallback();
      if (!(func === baseCallback && iteratee == null)) {
        iteratee = func(iteratee, thisArg, 3);
      }
      return (isSorted && getIndexOf() == baseIndexOf)
        ? sortedUniq(array, iteratee)
        : baseUniq(array, iteratee);
    }

    /**
     * This method is like `_.zip` except that it accepts an array of grouped
     * elements and creates an array regrouping the elements to their pre-`_.zip`
     * configuration.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array of grouped elements to process.
     * @returns {Array} Returns the new array of regrouped elements.
     * @example
     *
     * var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
     * // => [['fred', 30, true], ['barney', 40, false]]
     *
     * _.unzip(zipped);
     * // => [['fred', 'barney'], [30, 40], [true, false]]
     */
    function unzip(array) {
      var index = -1,
          length = (array && array.length && arrayMax(arrayMap(array, getLength))) >>> 0,
          result = Array(length);

      while (++index < length) {
        result[index] = arrayMap(array, baseProperty(index));
      }
      return result;
    }

    /**
     * Creates an array excluding all provided values using `SameValueZero` for
     * equality comparisons.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to filter.
     * @param {...*} [values] The values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.without([1, 2, 1, 3], 1, 2);
     * // => [3]
     */
    var without = restParam(function(array, values) {
      return (isArray(array) || isArguments(array))
        ? baseDifference(array, values)
        : [];
    });

    /**
     * Creates an array that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
     * of the provided arrays.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of values.
     * @example
     *
     * _.xor([1, 2], [4, 2]);
     * // => [1, 4]
     */
    function xor() {
      var index = -1,
          length = arguments.length;

      while (++index < length) {
        var array = arguments[index];
        if (isArray(array) || isArguments(array)) {
          var result = result
            ? baseDifference(result, array).concat(baseDifference(array, result))
            : array;
        }
      }
      return result ? baseUniq(result) : [];
    }

    /**
     * Creates an array of grouped elements, the first of which contains the first
     * elements of the given arrays, the second of which contains the second elements
     * of the given arrays, and so on.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to process.
     * @returns {Array} Returns the new array of grouped elements.
     * @example
     *
     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
     * // => [['fred', 30, true], ['barney', 40, false]]
     */
    var zip = restParam(unzip);

    /**
     * The inverse of `_.pairs`; this method returns an object composed from arrays
     * of property names and values. Provide either a single two dimensional array,
     * e.g. `[[key1, value1], [key2, value2]]` or two arrays, one of property names
     * and one of corresponding values.
     *
     * @static
     * @memberOf _
     * @alias object
     * @category Array
     * @param {Array} props The property names.
     * @param {Array} [values=[]] The property values.
     * @returns {Object} Returns the new object.
     * @example
     *
     * _.zipObject([['fred', 30], ['barney', 40]]);
     * // => { 'fred': 30, 'barney': 40 }
     *
     * _.zipObject(['fred', 'barney'], [30, 40]);
     * // => { 'fred': 30, 'barney': 40 }
     */
    function zipObject(props, values) {
      var index = -1,
          length = props ? props.length : 0,
          result = {};

      if (length && !values && !isArray(props[0])) {
        values = [];
      }
      while (++index < length) {
        var key = props[index];
        if (values) {
          result[key] = values[index];
        } else if (key) {
          result[key[0]] = key[1];
        }
      }
      return result;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a `lodash` object that wraps `value` with explicit method
     * chaining enabled.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to wrap.
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40 },
     *   { 'user': 'pebbles', 'age': 1 }
     * ];
     *
     * var youngest = _.chain(users)
     *   .sortBy('age')
     *   .map(function(chr) {
     *     return chr.user + ' is ' + chr.age;
     *   })
     *   .first()
     *   .value();
     * // => 'pebbles is 1'
     */
    function chain(value) {
      var result = lodash(value);
      result.__chain__ = true;
      return result;
    }

    /**
     * This method invokes `interceptor` and returns `value`. The interceptor is
     * bound to `thisArg` and invoked with one argument; (value). The purpose of
     * this method is to "tap into" a method chain in order to perform operations
     * on intermediate results within the chain.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to provide to `interceptor`.
     * @param {Function} interceptor The function to invoke.
     * @param {*} [thisArg] The `this` binding of `interceptor`.
     * @returns {*} Returns `value`.
     * @example
     *
     * _([1, 2, 3])
     *  .tap(function(array) {
     *    array.pop();
     *  })
     *  .reverse()
     *  .value();
     * // => [2, 1]
     */
    function tap(value, interceptor, thisArg) {
      interceptor.call(thisArg, value);
      return value;
    }

    /**
     * This method is like `_.tap` except that it returns the result of `interceptor`.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to provide to `interceptor`.
     * @param {Function} interceptor The function to invoke.
     * @param {*} [thisArg] The `this` binding of `interceptor`.
     * @returns {*} Returns the result of `interceptor`.
     * @example
     *
     * _('  abc  ')
     *  .chain()
     *  .trim()
     *  .thru(function(value) {
     *    return [value];
     *  })
     *  .value();
     * // => ['abc']
     */
    function thru(value, interceptor, thisArg) {
      return interceptor.call(thisArg, value);
    }

    /**
     * Enables explicit method chaining on the wrapper object.
     *
     * @name chain
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // without explicit chaining
     * _(users).first();
     * // => { 'user': 'barney', 'age': 36 }
     *
     * // with explicit chaining
     * _(users).chain()
     *   .first()
     *   .pick('user')
     *   .value();
     * // => { 'user': 'barney' }
     */
    function wrapperChain() {
      return chain(this);
    }

    /**
     * Executes the chained sequence and returns the wrapped result.
     *
     * @name commit
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var array = [1, 2];
     * var wrapper = _(array).push(3);
     *
     * console.log(array);
     * // => [1, 2]
     *
     * wrapper = wrapper.commit();
     * console.log(array);
     * // => [1, 2, 3]
     *
     * wrapper.last();
     * // => 3
     *
     * console.log(array);
     * // => [1, 2, 3]
     */
    function wrapperCommit() {
      return new LodashWrapper(this.value(), this.__chain__);
    }

    /**
     * Creates a clone of the chained sequence planting `value` as the wrapped value.
     *
     * @name plant
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new `lodash` wrapper instance.
     * @example
     *
     * var array = [1, 2];
     * var wrapper = _(array).map(function(value) {
     *   return Math.pow(value, 2);
     * });
     *
     * var other = [3, 4];
     * var otherWrapper = wrapper.plant(other);
     *
     * otherWrapper.value();
     * // => [9, 16]
     *
     * wrapper.value();
     * // => [1, 4]
     */
    function wrapperPlant(value) {
      var result,
          parent = this;

      while (parent instanceof baseLodash) {
        var clone = wrapperClone(parent);
        if (result) {
          previous.__wrapped__ = clone;
        } else {
          result = clone;
        }
        var previous = clone;
        parent = parent.__wrapped__;
      }
      previous.__wrapped__ = value;
      return result;
    }

    /**
     * Reverses the wrapped array so the first element becomes the last, the
     * second element becomes the second to last, and so on.
     *
     * **Note:** This method mutates the wrapped array.
     *
     * @name reverse
     * @memberOf _
     * @category Chain
     * @returns {Object} Returns the new reversed `lodash` wrapper instance.
     * @example
     *
     * var array = [1, 2, 3];
     *
     * _(array).reverse().value()
     * // => [3, 2, 1]
     *
     * console.log(array);
     * // => [3, 2, 1]
     */
    function wrapperReverse() {
      var value = this.__wrapped__;
      if (value instanceof LazyWrapper) {
        if (this.__actions__.length) {
          value = new LazyWrapper(this);
        }
        return new LodashWrapper(value.reverse(), this.__chain__);
      }
      return this.thru(function(value) {
        return value.reverse();
      });
    }

    /**
     * Produces the result of coercing the unwrapped value to a string.
     *
     * @name toString
     * @memberOf _
     * @category Chain
     * @returns {string} Returns the coerced string value.
     * @example
     *
     * _([1, 2, 3]).toString();
     * // => '1,2,3'
     */
    function wrapperToString() {
      return (this.value() + '');
    }

    /**
     * Executes the chained sequence to extract the unwrapped value.
     *
     * @name value
     * @memberOf _
     * @alias run, toJSON, valueOf
     * @category Chain
     * @returns {*} Returns the resolved unwrapped value.
     * @example
     *
     * _([1, 2, 3]).value();
     * // => [1, 2, 3]
     */
    function wrapperValue() {
      return baseWrapperValue(this.__wrapped__, this.__actions__);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates an array of elements corresponding to the given keys, or indexes,
     * of `collection`. Keys may be specified as individual arguments or as arrays
     * of keys.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {...(number|number[]|string|string[])} [props] The property names
     *  or indexes of elements to pick, specified individually or in arrays.
     * @returns {Array} Returns the new array of picked elements.
     * @example
     *
     * _.at(['a', 'b', 'c'], [0, 2]);
     * // => ['a', 'c']
     *
     * _.at(['barney', 'fred', 'pebbles'], 0, 2);
     * // => ['barney', 'pebbles']
     */
    var at = restParam(function(collection, props) {
      var length = collection ? getLength(collection) : 0;
      if (isLength(length)) {
        collection = toIterable(collection);
      }
      return baseAt(collection, baseFlatten(props));
    });

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is the number of times the key was returned by `iteratee`.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * _.countBy([4.3, 6.1, 6.4], function(n) {
     *   return Math.floor(n);
     * });
     * // => { '4': 1, '6': 2 }
     *
     * _.countBy([4.3, 6.1, 6.4], function(n) {
     *   return this.floor(n);
     * }, Math);
     * // => { '4': 1, '6': 2 }
     *
     * _.countBy(['one', 'two', 'three'], 'length');
     * // => { '3': 2, '5': 1 }
     */
    var countBy = createAggregator(function(result, value, key) {
      hasOwnProperty.call(result, key) ? ++result[key] : (result[key] = 1);
    });

    /**
     * Checks if `predicate` returns truthy for **all** elements of `collection`.
     * The predicate is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias all
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`.
     * @example
     *
     * _.every([true, 1, null, 'yes'], Boolean);
     * // => false
     *
     * var users = [
     *   { 'user': 'barney', 'active': false },
     *   { 'user': 'fred',   'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.every(users, { 'user': 'barney', 'active': false });
     * // => false
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.every(users, 'active', false);
     * // => true
     *
     * // using the `_.property` callback shorthand
     * _.every(users, 'active');
     * // => false
     */
    function every(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayEvery : baseEvery;
      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
        predicate = null;
      }
      if (typeof predicate != 'function' || thisArg !== undefined) {
        predicate = getCallback(predicate, thisArg, 3);
      }
      return func(collection, predicate);
    }

    /**
     * Iterates over elements of `collection`, returning an array of all elements
     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
     * invoked with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias select
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * _.filter([4, 5, 6], function(n) {
     *   return n % 2 == 0;
     * });
     * // => [4, 6]
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': true },
     *   { 'user': 'fred',   'age': 40, 'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.filter(users, { 'age': 36, 'active': true }), 'user');
     * // => ['barney']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.filter(users, 'active', false), 'user');
     * // => ['fred']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.filter(users, 'active'), 'user');
     * // => ['barney']
     */
    function filter(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayFilter : baseFilter;
      predicate = getCallback(predicate, thisArg, 3);
      return func(collection, predicate);
    }

    /**
     * Iterates over elements of `collection`, returning the first element
     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
     * invoked with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias detect
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36, 'active': true },
     *   { 'user': 'fred',    'age': 40, 'active': false },
     *   { 'user': 'pebbles', 'age': 1,  'active': true }
     * ];
     *
     * _.result(_.find(users, function(chr) {
     *   return chr.age < 40;
     * }), 'user');
     * // => 'barney'
     *
     * // using the `_.matches` callback shorthand
     * _.result(_.find(users, { 'age': 1, 'active': true }), 'user');
     * // => 'pebbles'
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.result(_.find(users, 'active', false), 'user');
     * // => 'fred'
     *
     * // using the `_.property` callback shorthand
     * _.result(_.find(users, 'active'), 'user');
     * // => 'barney'
     */
    var find = createFind(baseEach);

    /**
     * This method is like `_.find` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * _.findLast([1, 2, 3, 4], function(n) {
     *   return n % 2 == 1;
     * });
     * // => 3
     */
    var findLast = createFind(baseEachRight, true);

    /**
     * Performs a deep comparison between each element in `collection` and the
     * source object, returning the first element that has equivalent property
     * values.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. For comparing a single
     * own or inherited property value see `_.matchesProperty`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Object} source The object of property values to match.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': true },
     *   { 'user': 'fred',   'age': 40, 'active': false }
     * ];
     *
     * _.result(_.findWhere(users, { 'age': 36, 'active': true }), 'user');
     * // => 'barney'
     *
     * _.result(_.findWhere(users, { 'age': 40, 'active': false }), 'user');
     * // => 'fred'
     */
    function findWhere(collection, source) {
      return find(collection, baseMatches(source));
    }

    /**
     * Iterates over elements of `collection` invoking `iteratee` for each element.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection). Iteratee functions may exit iteration early
     * by explicitly returning `false`.
     *
     * **Note:** As with other "Collections" methods, objects with a "length" property
     * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
     * may be used for object iteration.
     *
     * @static
     * @memberOf _
     * @alias each
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array|Object|string} Returns `collection`.
     * @example
     *
     * _([1, 2]).forEach(function(n) {
     *   console.log(n);
     * }).value();
     * // => logs each value from left to right and returns the array
     *
     * _.forEach({ 'a': 1, 'b': 2 }, function(n, key) {
     *   console.log(n, key);
     * });
     * // => logs each value-key pair and returns the object (iteration order is not guaranteed)
     */
    var forEach = createForEach(arrayEach, baseEach);

    /**
     * This method is like `_.forEach` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @alias eachRight
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array|Object|string} Returns `collection`.
     * @example
     *
     * _([1, 2]).forEachRight(function(n) {
     *   console.log(n);
     * }).value();
     * // => logs each value from right to left and returns the array
     */
    var forEachRight = createForEach(arrayEachRight, baseEachRight);

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is an array of the elements responsible for generating the key.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * _.groupBy([4.2, 6.1, 6.4], function(n) {
     *   return Math.floor(n);
     * });
     * // => { '4': [4.2], '6': [6.1, 6.4] }
     *
     * _.groupBy([4.2, 6.1, 6.4], function(n) {
     *   return this.floor(n);
     * }, Math);
     * // => { '4': [4.2], '6': [6.1, 6.4] }
     *
     * // using the `_.property` callback shorthand
     * _.groupBy(['one', 'two', 'three'], 'length');
     * // => { '3': ['one', 'two'], '5': ['three'] }
     */
    var groupBy = createAggregator(function(result, value, key) {
      if (hasOwnProperty.call(result, key)) {
        result[key].push(value);
      } else {
        result[key] = [value];
      }
    });

    /**
     * Checks if `value` is in `collection` using `SameValueZero` for equality
     * comparisons. If `fromIndex` is negative, it is used as the offset from
     * the end of `collection`.
     *
     * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * comparisons are like strict equality comparisons, e.g. `===`, except that
     * `NaN` matches `NaN`.
     *
     * @static
     * @memberOf _
     * @alias contains, include
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {*} target The value to search for.
     * @param {number} [fromIndex=0] The index to search from.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
     * @returns {boolean} Returns `true` if a matching element is found, else `false`.
     * @example
     *
     * _.includes([1, 2, 3], 1);
     * // => true
     *
     * _.includes([1, 2, 3], 1, 2);
     * // => false
     *
     * _.includes({ 'user': 'fred', 'age': 40 }, 'fred');
     * // => true
     *
     * _.includes('pebbles', 'eb');
     * // => true
     */
    function includes(collection, target, fromIndex, guard) {
      var length = collection ? getLength(collection) : 0;
      if (!isLength(length)) {
        collection = values(collection);
        length = collection.length;
      }
      if (!length) {
        return false;
      }
      if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
        fromIndex = 0;
      } else {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
      }
      return (typeof collection == 'string' || !isArray(collection) && isString(collection))
        ? (fromIndex < length && collection.indexOf(target, fromIndex) > -1)
        : (getIndexOf(collection, target, fromIndex) > -1);
    }

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is the last element responsible for generating the key. The
     * iteratee function is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * var keyData = [
     *   { 'dir': 'left', 'code': 97 },
     *   { 'dir': 'right', 'code': 100 }
     * ];
     *
     * _.indexBy(keyData, 'dir');
     * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
     *
     * _.indexBy(keyData, function(object) {
     *   return String.fromCharCode(object.code);
     * });
     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
     *
     * _.indexBy(keyData, function(object) {
     *   return this.fromCharCode(object.code);
     * }, String);
     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
     */
    var indexBy = createAggregator(function(result, value, key) {
      result[key] = value;
    });

    /**
     * Invokes the method at `path` on each element in `collection`, returning
     * an array of the results of each invoked method. Any additional arguments
     * are provided to each invoked method. If `methodName` is a function it is
     * invoked for, and `this` bound to, each element in `collection`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Array|Function|string} path The path of the method to invoke or
     *  the function invoked per iteration.
     * @param {...*} [args] The arguments to invoke the method with.
     * @returns {Array} Returns the array of results.
     * @example
     *
     * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
     * // => [[1, 5, 7], [1, 2, 3]]
     *
     * _.invoke([123, 456], String.prototype.split, '');
     * // => [['1', '2', '3'], ['4', '5', '6']]
     */
    var invoke = restParam(function(collection, path, args) {
      var index = -1,
          isFunc = typeof path == 'function',
          isProp = isKey(path),
          length = getLength(collection),
          result = isLength(length) ? Array(length) : [];

      baseEach(collection, function(value) {
        var func = isFunc ? path : (isProp && value != null && value[path]);
        result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
      });
      return result;
    });

    /**
     * Creates an array of values by running each element in `collection` through
     * `iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * Many lodash methods are guarded to work as interatees for methods like
     * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
     *
     * The guarded methods are:
     * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`, `drop`,
     * `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`, `parseInt`,
     * `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`, `trimLeft`,
     * `trimRight`, `trunc`, `random`, `range`, `sample`, `some`, `uniq`, and `words`
     *
     * @static
     * @memberOf _
     * @alias collect
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new mapped array.
     * @example
     *
     * function timesThree(n) {
     *   return n * 3;
     * }
     *
     * _.map([1, 2], timesThree);
     * // => [3, 6]
     *
     * _.map({ 'a': 1, 'b': 2 }, timesThree);
     * // => [3, 6] (iteration order is not guaranteed)
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * // using the `_.property` callback shorthand
     * _.map(users, 'user');
     * // => ['barney', 'fred']
     */
    function map(collection, iteratee, thisArg) {
      var func = isArray(collection) ? arrayMap : baseMap;
      iteratee = getCallback(iteratee, thisArg, 3);
      return func(collection, iteratee);
    }

    /**
     * Creates an array of elements split into two groups, the first of which
     * contains elements `predicate` returns truthy for, while the second of which
     * contains elements `predicate` returns falsey for. The predicate is bound
     * to `thisArg` and invoked with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the array of grouped elements.
     * @example
     *
     * _.partition([1, 2, 3], function(n) {
     *   return n % 2;
     * });
     * // => [[1, 3], [2]]
     *
     * _.partition([1.2, 2.3, 3.4], function(n) {
     *   return this.floor(n) % 2;
     * }, Math);
     * // => [[1.2, 3.4], [2.3]]
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36, 'active': false },
     *   { 'user': 'fred',    'age': 40, 'active': true },
     *   { 'user': 'pebbles', 'age': 1,  'active': false }
     * ];
     *
     * var mapper = function(array) {
     *   return _.pluck(array, 'user');
     * };
     *
     * // using the `_.matches` callback shorthand
     * _.map(_.partition(users, { 'age': 1, 'active': false }), mapper);
     * // => [['pebbles'], ['barney', 'fred']]
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.map(_.partition(users, 'active', false), mapper);
     * // => [['barney', 'pebbles'], ['fred']]
     *
     * // using the `_.property` callback shorthand
     * _.map(_.partition(users, 'active'), mapper);
     * // => [['fred'], ['barney', 'pebbles']]
     */
    var partition = createAggregator(function(result, value, key) {
      result[key ? 0 : 1].push(value);
    }, function() { return [[], []]; });

    /**
     * Gets the property value of `path` from all elements in `collection`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Array|string} path The path of the property to pluck.
     * @returns {Array} Returns the property values.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.pluck(users, 'user');
     * // => ['barney', 'fred']
     *
     * var userIndex = _.indexBy(users, 'user');
     * _.pluck(userIndex, 'age');
     * // => [36, 40] (iteration order is not guaranteed)
     */
    function pluck(collection, path) {
      return map(collection, property(path));
    }

    /**
     * Reduces `collection` to a value which is the accumulated result of running
     * each element in `collection` through `iteratee`, where each successive
     * invocation is supplied the return value of the previous. If `accumulator`
     * is not provided the first element of `collection` is used as the initial
     * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
     * (accumulator, value, index|key, collection).
     *
     * Many lodash methods are guarded to work as interatees for methods like
     * `_.reduce`, `_.reduceRight`, and `_.transform`.
     *
     * The guarded methods are:
     * `assign`, `defaults`, `includes`, `merge`, `sortByAll`, and `sortByOrder`
     *
     * @static
     * @memberOf _
     * @alias foldl, inject
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * _.reduce([1, 2], function(total, n) {
     *   return total + n;
     * });
     * // => 3
     *
     * _.reduce({ 'a': 1, 'b': 2 }, function(result, n, key) {
     *   result[key] = n * 3;
     *   return result;
     * }, {});
     * // => { 'a': 3, 'b': 6 } (iteration order is not guaranteed)
     */
    var reduce = createReduce(arrayReduce, baseEach);

    /**
     * This method is like `_.reduce` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @alias foldr
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * var array = [[0, 1], [2, 3], [4, 5]];
     *
     * _.reduceRight(array, function(flattened, other) {
     *   return flattened.concat(other);
     * }, []);
     * // => [4, 5, 2, 3, 0, 1]
     */
    var reduceRight =  createReduce(arrayReduceRight, baseEachRight);

    /**
     * The opposite of `_.filter`; this method returns the elements of `collection`
     * that `predicate` does **not** return truthy for.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * _.reject([1, 2, 3, 4], function(n) {
     *   return n % 2 == 0;
     * });
     * // => [1, 3]
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': false },
     *   { 'user': 'fred',   'age': 40, 'active': true }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.pluck(_.reject(users, { 'age': 40, 'active': true }), 'user');
     * // => ['barney']
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.pluck(_.reject(users, 'active', false), 'user');
     * // => ['fred']
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.reject(users, 'active'), 'user');
     * // => ['barney']
     */
    function reject(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayFilter : baseFilter;
      predicate = getCallback(predicate, thisArg, 3);
      return func(collection, function(value, index, collection) {
        return !predicate(value, index, collection);
      });
    }

    /**
     * Gets a random element or `n` random elements from a collection.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to sample.
     * @param {number} [n] The number of elements to sample.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {*} Returns the random sample(s).
     * @example
     *
     * _.sample([1, 2, 3, 4]);
     * // => 2
     *
     * _.sample([1, 2, 3, 4], 2);
     * // => [3, 1]
     */
    function sample(collection, n, guard) {
      if (guard ? isIterateeCall(collection, n, guard) : n == null) {
        collection = toIterable(collection);
        var length = collection.length;
        return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
      }
      var result = shuffle(collection);
      result.length = nativeMin(n < 0 ? 0 : (+n || 0), result.length);
      return result;
    }

    /**
     * Creates an array of shuffled values, using a version of the
     * [Fisher-Yates shuffle](https://en.wikipedia.org/wiki/Fisher-Yates_shuffle).
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to shuffle.
     * @returns {Array} Returns the new shuffled array.
     * @example
     *
     * _.shuffle([1, 2, 3, 4]);
     * // => [4, 1, 3, 2]
     */
    function shuffle(collection) {
      collection = toIterable(collection);

      var index = -1,
          length = collection.length,
          result = Array(length);

      while (++index < length) {
        var rand = baseRandom(0, index);
        if (index != rand) {
          result[index] = result[rand];
        }
        result[rand] = collection[index];
      }
      return result;
    }

    /**
     * Gets the size of `collection` by returning its length for array-like
     * values or the number of own enumerable properties for objects.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to inspect.
     * @returns {number} Returns the size of `collection`.
     * @example
     *
     * _.size([1, 2, 3]);
     * // => 3
     *
     * _.size({ 'a': 1, 'b': 2 });
     * // => 2
     *
     * _.size('pebbles');
     * // => 7
     */
    function size(collection) {
      var length = collection ? getLength(collection) : 0;
      return isLength(length) ? length : keys(collection).length;
    }

    /**
     * Checks if `predicate` returns truthy for **any** element of `collection`.
     * The function returns as soon as it finds a passing value and does not iterate
     * over the entire collection. The predicate is bound to `thisArg` and invoked
     * with three arguments: (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @alias any
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     * @example
     *
     * _.some([null, 0, 'yes', false], Boolean);
     * // => true
     *
     * var users = [
     *   { 'user': 'barney', 'active': true },
     *   { 'user': 'fred',   'active': false }
     * ];
     *
     * // using the `_.matches` callback shorthand
     * _.some(users, { 'user': 'barney', 'active': false });
     * // => false
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.some(users, 'active', false);
     * // => true
     *
     * // using the `_.property` callback shorthand
     * _.some(users, 'active');
     * // => true
     */
    function some(collection, predicate, thisArg) {
      var func = isArray(collection) ? arraySome : baseSome;
      if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
        predicate = null;
      }
      if (typeof predicate != 'function' || thisArg !== undefined) {
        predicate = getCallback(predicate, thisArg, 3);
      }
      return func(collection, predicate);
    }

    /**
     * Creates an array of elements, sorted in ascending order by the results of
     * running each element in a collection through `iteratee`. This method performs
     * a stable sort, that is, it preserves the original sort order of equal elements.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments:
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * _.sortBy([1, 2, 3], function(n) {
     *   return Math.sin(n);
     * });
     * // => [3, 1, 2]
     *
     * _.sortBy([1, 2, 3], function(n) {
     *   return this.sin(n);
     * }, Math);
     * // => [3, 1, 2]
     *
     * var users = [
     *   { 'user': 'fred' },
     *   { 'user': 'pebbles' },
     *   { 'user': 'barney' }
     * ];
     *
     * // using the `_.property` callback shorthand
     * _.pluck(_.sortBy(users, 'user'), 'user');
     * // => ['barney', 'fred', 'pebbles']
     */
    function sortBy(collection, iteratee, thisArg) {
      if (collection == null) {
        return [];
      }
      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
        iteratee = null;
      }
      var index = -1;
      iteratee = getCallback(iteratee, thisArg, 3);

      var result = baseMap(collection, function(value, key, collection) {
        return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
      });
      return baseSortBy(result, compareAscending);
    }

    /**
     * This method is like `_.sortBy` except that it can sort by multiple iteratees
     * or property names.
     *
     * If a property name is provided for an iteratee the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If an object is provided for an iteratee the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
     *  The iteratees to sort by, specified as individual values or arrays of values.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * var users = [
     *   { 'user': 'fred',   'age': 48 },
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 42 },
     *   { 'user': 'barney', 'age': 34 }
     * ];
     *
     * _.map(_.sortByAll(users, ['user', 'age']), _.values);
     * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
     *
     * _.map(_.sortByAll(users, 'user', function(chr) {
     *   return Math.floor(chr.age / 10);
     * }), _.values);
     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
     */
    var sortByAll = restParam(function(collection, iteratees) {
      if (collection == null) {
        return [];
      }
      var guard = iteratees[2];
      if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
        iteratees.length = 1;
      }
      return baseSortByOrder(collection, baseFlatten(iteratees), []);
    });

    /**
     * This method is like `_.sortByAll` except that it allows specifying the
     * sort orders of the iteratees to sort by. A truthy value in `orders` will
     * sort the corresponding property name in ascending order while a falsey
     * value will sort it in descending order.
     *
     * If a property name is provided for an iteratee the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If an object is provided for an iteratee the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
     * @param {boolean[]} orders The sort orders of `iteratees`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * var users = [
     *   { 'user': 'fred',   'age': 48 },
     *   { 'user': 'barney', 'age': 34 },
     *   { 'user': 'fred',   'age': 42 },
     *   { 'user': 'barney', 'age': 36 }
     * ];
     *
     * // sort by `user` in ascending order and by `age` in descending order
     * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
     * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
     */
    function sortByOrder(collection, iteratees, orders, guard) {
      if (collection == null) {
        return [];
      }
      if (guard && isIterateeCall(iteratees, orders, guard)) {
        orders = null;
      }
      if (!isArray(iteratees)) {
        iteratees = iteratees == null ? [] : [iteratees];
      }
      if (!isArray(orders)) {
        orders = orders == null ? [] : [orders];
      }
      return baseSortByOrder(collection, iteratees, orders);
    }

    /**
     * Performs a deep comparison between each element in `collection` and the
     * source object, returning an array of all elements that have equivalent
     * property values.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. For comparing a single
     * own or inherited property value see `_.matchesProperty`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Object} source The object of property values to match.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': false, 'pets': ['hoppy'] },
     *   { 'user': 'fred',   'age': 40, 'active': true, 'pets': ['baby puss', 'dino'] }
     * ];
     *
     * _.pluck(_.where(users, { 'age': 36, 'active': false }), 'user');
     * // => ['barney']
     *
     * _.pluck(_.where(users, { 'pets': ['dino'] }), 'user');
     * // => ['fred']
     */
    function where(collection, source) {
      return filter(collection, baseMatches(source));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Gets the number of milliseconds that have elapsed since the Unix epoch
     * (1 January 1970 00:00:00 UTC).
     *
     * @static
     * @memberOf _
     * @category Date
     * @example
     *
     * _.defer(function(stamp) {
     *   console.log(_.now() - stamp);
     * }, _.now());
     * // => logs the number of milliseconds it took for the deferred function to be invoked
     */
    var now = nativeNow || function() {
      return new Date().getTime();
    };

    /*------------------------------------------------------------------------*/

    /**
     * The opposite of `_.before`; this method creates a function that invokes
     * `func` once it is called `n` or more times.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {number} n The number of calls before `func` is invoked.
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * var saves = ['profile', 'settings'];
     *
     * var done = _.after(saves.length, function() {
     *   console.log('done saving!');
     * });
     *
     * _.forEach(saves, function(type) {
     *   asyncSave({ 'type': type, 'complete': done });
     * });
     * // => logs 'done saving!' after the two async saves have completed
     */
    function after(n, func) {
      if (typeof func != 'function') {
        if (typeof n == 'function') {
          var temp = n;
          n = func;
          func = temp;
        } else {
          throw new TypeError(FUNC_ERROR_TEXT);
        }
      }
      n = nativeIsFinite(n = +n) ? n : 0;
      return function() {
        if (--n < 1) {
          return func.apply(this, arguments);
        }
      };
    }

    /**
     * Creates a function that accepts up to `n` arguments ignoring any
     * additional arguments.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to cap arguments for.
     * @param {number} [n=func.length] The arity cap.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new function.
     * @example
     *
     * _.map(['6', '8', '10'], _.ary(parseInt, 1));
     * // => [6, 8, 10]
     */
    function ary(func, n, guard) {
      if (guard && isIterateeCall(func, n, guard)) {
        n = null;
      }
      n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
      return createWrapper(func, ARY_FLAG, null, null, null, null, n);
    }

    /**
     * Creates a function that invokes `func`, with the `this` binding and arguments
     * of the created function, while it is called less than `n` times. Subsequent
     * calls to the created function return the result of the last `func` invocation.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {number} n The number of calls at which `func` is no longer invoked.
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * jQuery('#add').on('click', _.before(5, addContactToList));
     * // => allows adding up to 4 contacts to the list
     */
    function before(n, func) {
      var result;
      if (typeof func != 'function') {
        if (typeof n == 'function') {
          var temp = n;
          n = func;
          func = temp;
        } else {
          throw new TypeError(FUNC_ERROR_TEXT);
        }
      }
      return function() {
        if (--n > 0) {
          result = func.apply(this, arguments);
        }
        if (n <= 1) {
          func = null;
        }
        return result;
      };
    }

    /**
     * Creates a function that invokes `func` with the `this` binding of `thisArg`
     * and prepends any additional `_.bind` arguments to those provided to the
     * bound function.
     *
     * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
     * may be used as a placeholder for partially applied arguments.
     *
     * **Note:** Unlike native `Function#bind` this method does not set the "length"
     * property of bound functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to bind.
     * @param {*} thisArg The `this` binding of `func`.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new bound function.
     * @example
     *
     * var greet = function(greeting, punctuation) {
     *   return greeting + ' ' + this.user + punctuation;
     * };
     *
     * var object = { 'user': 'fred' };
     *
     * var bound = _.bind(greet, object, 'hi');
     * bound('!');
     * // => 'hi fred!'
     *
     * // using placeholders
     * var bound = _.bind(greet, object, _, '!');
     * bound('hi');
     * // => 'hi fred!'
     */
    var bind = restParam(function(func, thisArg, partials) {
      var bitmask = BIND_FLAG;
      if (partials.length) {
        var holders = replaceHolders(partials, bind.placeholder);
        bitmask |= PARTIAL_FLAG;
      }
      return createWrapper(func, bitmask, thisArg, partials, holders);
    });

    /**
     * Binds methods of an object to the object itself, overwriting the existing
     * method. Method names may be specified as individual arguments or as arrays
     * of method names. If no method names are provided all enumerable function
     * properties, own and inherited, of `object` are bound.
     *
     * **Note:** This method does not set the "length" property of bound functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Object} object The object to bind and assign the bound methods to.
     * @param {...(string|string[])} [methodNames] The object method names to bind,
     *  specified as individual method names or arrays of method names.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var view = {
     *   'label': 'docs',
     *   'onClick': function() {
     *     console.log('clicked ' + this.label);
     *   }
     * };
     *
     * _.bindAll(view);
     * jQuery('#docs').on('click', view.onClick);
     * // => logs 'clicked docs' when the element is clicked
     */
    var bindAll = restParam(function(object, methodNames) {
      methodNames = methodNames.length ? baseFlatten(methodNames) : functions(object);

      var index = -1,
          length = methodNames.length;

      while (++index < length) {
        var key = methodNames[index];
        object[key] = createWrapper(object[key], BIND_FLAG, object);
      }
      return object;
    });

    /**
     * Creates a function that invokes the method at `object[key]` and prepends
     * any additional `_.bindKey` arguments to those provided to the bound function.
     *
     * This method differs from `_.bind` by allowing bound functions to reference
     * methods that may be redefined or don't yet exist.
     * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
     * for more details.
     *
     * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for partially applied arguments.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Object} object The object the method belongs to.
     * @param {string} key The key of the method.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new bound function.
     * @example
     *
     * var object = {
     *   'user': 'fred',
     *   'greet': function(greeting, punctuation) {
     *     return greeting + ' ' + this.user + punctuation;
     *   }
     * };
     *
     * var bound = _.bindKey(object, 'greet', 'hi');
     * bound('!');
     * // => 'hi fred!'
     *
     * object.greet = function(greeting, punctuation) {
     *   return greeting + 'ya ' + this.user + punctuation;
     * };
     *
     * bound('!');
     * // => 'hiya fred!'
     *
     * // using placeholders
     * var bound = _.bindKey(object, 'greet', _, '!');
     * bound('hi');
     * // => 'hiya fred!'
     */
    var bindKey = restParam(function(object, key, partials) {
      var bitmask = BIND_FLAG | BIND_KEY_FLAG;
      if (partials.length) {
        var holders = replaceHolders(partials, bindKey.placeholder);
        bitmask |= PARTIAL_FLAG;
      }
      return createWrapper(key, bitmask, object, partials, holders);
    });

    /**
     * Creates a function that accepts one or more arguments of `func` that when
     * called either invokes `func` returning its result, if all `func` arguments
     * have been provided, or returns a function that accepts one or more of the
     * remaining `func` arguments, and so on. The arity of `func` may be specified
     * if `func.length` is not sufficient.
     *
     * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
     * may be used as a placeholder for provided arguments.
     *
     * **Note:** This method does not set the "length" property of curried functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to curry.
     * @param {number} [arity=func.length] The arity of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new curried function.
     * @example
     *
     * var abc = function(a, b, c) {
     *   return [a, b, c];
     * };
     *
     * var curried = _.curry(abc);
     *
     * curried(1)(2)(3);
     * // => [1, 2, 3]
     *
     * curried(1, 2)(3);
     * // => [1, 2, 3]
     *
     * curried(1, 2, 3);
     * // => [1, 2, 3]
     *
     * // using placeholders
     * curried(1)(_, 3)(2);
     * // => [1, 2, 3]
     */
    var curry = createCurry(CURRY_FLAG);

    /**
     * This method is like `_.curry` except that arguments are applied to `func`
     * in the manner of `_.partialRight` instead of `_.partial`.
     *
     * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for provided arguments.
     *
     * **Note:** This method does not set the "length" property of curried functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to curry.
     * @param {number} [arity=func.length] The arity of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new curried function.
     * @example
     *
     * var abc = function(a, b, c) {
     *   return [a, b, c];
     * };
     *
     * var curried = _.curryRight(abc);
     *
     * curried(3)(2)(1);
     * // => [1, 2, 3]
     *
     * curried(2, 3)(1);
     * // => [1, 2, 3]
     *
     * curried(1, 2, 3);
     * // => [1, 2, 3]
     *
     * // using placeholders
     * curried(3)(1, _)(2);
     * // => [1, 2, 3]
     */
    var curryRight = createCurry(CURRY_RIGHT_FLAG);

    /**
     * Creates a function that delays invoking `func` until after `wait` milliseconds
     * have elapsed since the last time it was invoked. The created function comes
     * with a `cancel` method to cancel delayed invocations. Provide an options
     * object to indicate that `func` should be invoked on the leading and/or
     * trailing edge of the `wait` timeout. Subsequent calls to the debounced
     * function return the result of the last `func` invocation.
     *
     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
     * on the trailing edge of the timeout only if the the debounced function is
     * invoked more than once during the `wait` timeout.
     *
     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
     * for details over the differences between `_.debounce` and `_.throttle`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to debounce.
     * @param {number} [wait=0] The number of milliseconds to delay.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.leading=false] Specify invoking on the leading
     *  edge of the timeout.
     * @param {number} [options.maxWait] The maximum time `func` is allowed to be
     *  delayed before it is invoked.
     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
     *  edge of the timeout.
     * @returns {Function} Returns the new debounced function.
     * @example
     *
     * // avoid costly calculations while the window size is in flux
     * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
     *
     * // invoke `sendMail` when the click event is fired, debouncing subsequent calls
     * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
     *   'leading': true,
     *   'trailing': false
     * }));
     *
     * // ensure `batchLog` is invoked once after 1 second of debounced calls
     * var source = new EventSource('/stream');
     * jQuery(source).on('message', _.debounce(batchLog, 250, {
     *   'maxWait': 1000
     * }));
     *
     * // cancel a debounced call
     * var todoChanges = _.debounce(batchLog, 1000);
     * Object.observe(models.todo, todoChanges);
     *
     * Object.observe(models, function(changes) {
     *   if (_.find(changes, { 'user': 'todo', 'type': 'delete'})) {
     *     todoChanges.cancel();
     *   }
     * }, ['delete']);
     *
     * // ...at some point `models.todo` is changed
     * models.todo.completed = true;
     *
     * // ...before 1 second has passed `models.todo` is deleted
     * // which cancels the debounced `todoChanges` call
     * delete models.todo;
     */
    function debounce(func, wait, options) {
      var args,
          maxTimeoutId,
          result,
          stamp,
          thisArg,
          timeoutId,
          trailingCall,
          lastCalled = 0,
          maxWait = false,
          trailing = true;

      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      wait = wait < 0 ? 0 : (+wait || 0);
      if (options === true) {
        var leading = true;
        trailing = false;
      } else if (isObject(options)) {
        leading = options.leading;
        maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
        trailing = 'trailing' in options ? options.trailing : trailing;
      }

      function cancel() {
        if (timeoutId) {
          clearTimeout(timeoutId);
        }
        if (maxTimeoutId) {
          clearTimeout(maxTimeoutId);
        }
        maxTimeoutId = timeoutId = trailingCall = undefined;
      }

      function delayed() {
        var remaining = wait - (now() - stamp);
        if (remaining <= 0 || remaining > wait) {
          if (maxTimeoutId) {
            clearTimeout(maxTimeoutId);
          }
          var isCalled = trailingCall;
          maxTimeoutId = timeoutId = trailingCall = undefined;
          if (isCalled) {
            lastCalled = now();
            result = func.apply(thisArg, args);
            if (!timeoutId && !maxTimeoutId) {
              args = thisArg = null;
            }
          }
        } else {
          timeoutId = setTimeout(delayed, remaining);
        }
      }

      function maxDelayed() {
        if (timeoutId) {
          clearTimeout(timeoutId);
        }
        maxTimeoutId = timeoutId = trailingCall = undefined;
        if (trailing || (maxWait !== wait)) {
          lastCalled = now();
          result = func.apply(thisArg, args);
          if (!timeoutId && !maxTimeoutId) {
            args = thisArg = null;
          }
        }
      }

      function debounced() {
        args = arguments;
        stamp = now();
        thisArg = this;
        trailingCall = trailing && (timeoutId || !leading);

        if (maxWait === false) {
          var leadingCall = leading && !timeoutId;
        } else {
          if (!maxTimeoutId && !leading) {
            lastCalled = stamp;
          }
          var remaining = maxWait - (stamp - lastCalled),
              isCalled = remaining <= 0 || remaining > maxWait;

          if (isCalled) {
            if (maxTimeoutId) {
              maxTimeoutId = clearTimeout(maxTimeoutId);
            }
            lastCalled = stamp;
            result = func.apply(thisArg, args);
          }
          else if (!maxTimeoutId) {
            maxTimeoutId = setTimeout(maxDelayed, remaining);
          }
        }
        if (isCalled && timeoutId) {
          timeoutId = clearTimeout(timeoutId);
        }
        else if (!timeoutId && wait !== maxWait) {
          timeoutId = setTimeout(delayed, wait);
        }
        if (leadingCall) {
          isCalled = true;
          result = func.apply(thisArg, args);
        }
        if (isCalled && !timeoutId && !maxTimeoutId) {
          args = thisArg = null;
        }
        return result;
      }
      debounced.cancel = cancel;
      return debounced;
    }

    /**
     * Defers invoking the `func` until the current call stack has cleared. Any
     * additional arguments are provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to defer.
     * @param {...*} [args] The arguments to invoke the function with.
     * @returns {number} Returns the timer id.
     * @example
     *
     * _.defer(function(text) {
     *   console.log(text);
     * }, 'deferred');
     * // logs 'deferred' after one or more milliseconds
     */
    var defer = restParam(function(func, args) {
      return baseDelay(func, 1, args);
    });

    /**
     * Invokes `func` after `wait` milliseconds. Any additional arguments are
     * provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to delay.
     * @param {number} wait The number of milliseconds to delay invocation.
     * @param {...*} [args] The arguments to invoke the function with.
     * @returns {number} Returns the timer id.
     * @example
     *
     * _.delay(function(text) {
     *   console.log(text);
     * }, 1000, 'later');
     * // => logs 'later' after one second
     */
    var delay = restParam(function(func, wait, args) {
      return baseDelay(func, wait, args);
    });

    /**
     * Creates a function that returns the result of invoking the provided
     * functions with the `this` binding of the created function, where each
     * successive invocation is supplied the return value of the previous.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {...Function} [funcs] Functions to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function square(n) {
     *   return n * n;
     * }
     *
     * var addSquare = _.flow(_.add, square);
     * addSquare(1, 2);
     * // => 9
     */
    var flow = createFlow();

    /**
     * This method is like `_.flow` except that it creates a function that
     * invokes the provided functions from right to left.
     *
     * @static
     * @memberOf _
     * @alias backflow, compose
     * @category Function
     * @param {...Function} [funcs] Functions to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function square(n) {
     *   return n * n;
     * }
     *
     * var addSquare = _.flowRight(square, _.add);
     * addSquare(1, 2);
     * // => 9
     */
    var flowRight = createFlow(true);

    /**
     * Creates a function that memoizes the result of `func`. If `resolver` is
     * provided it determines the cache key for storing the result based on the
     * arguments provided to the memoized function. By default, the first argument
     * provided to the memoized function is coerced to a string and used as the
     * cache key. The `func` is invoked with the `this` binding of the memoized
     * function.
     *
     * **Note:** The cache is exposed as the `cache` property on the memoized
     * function. Its creation may be customized by replacing the `_.memoize.Cache`
     * constructor with one whose instances implement the [`Map`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-map-prototype-object)
     * method interface of `get`, `has`, and `set`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to have its output memoized.
     * @param {Function} [resolver] The function to resolve the cache key.
     * @returns {Function} Returns the new memoizing function.
     * @example
     *
     * var upperCase = _.memoize(function(string) {
     *   return string.toUpperCase();
     * });
     *
     * upperCase('fred');
     * // => 'FRED'
     *
     * // modifying the result cache
     * upperCase.cache.set('fred', 'BARNEY');
     * upperCase('fred');
     * // => 'BARNEY'
     *
     * // replacing `_.memoize.Cache`
     * var object = { 'user': 'fred' };
     * var other = { 'user': 'barney' };
     * var identity = _.memoize(_.identity);
     *
     * identity(object);
     * // => { 'user': 'fred' }
     * identity(other);
     * // => { 'user': 'fred' }
     *
     * _.memoize.Cache = WeakMap;
     * var identity = _.memoize(_.identity);
     *
     * identity(object);
     * // => { 'user': 'fred' }
     * identity(other);
     * // => { 'user': 'barney' }
     */
    function memoize(func, resolver) {
      if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var memoized = function() {
        var args = arguments,
            cache = memoized.cache,
            key = resolver ? resolver.apply(this, args) : args[0];

        if (cache.has(key)) {
          return cache.get(key);
        }
        var result = func.apply(this, args);
        cache.set(key, result);
        return result;
      };
      memoized.cache = new memoize.Cache;
      return memoized;
    }

    /**
     * Creates a function that negates the result of the predicate `func`. The
     * `func` predicate is invoked with the `this` binding and arguments of the
     * created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} predicate The predicate to negate.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function isEven(n) {
     *   return n % 2 == 0;
     * }
     *
     * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
     * // => [1, 3, 5]
     */
    function negate(predicate) {
      if (typeof predicate != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function() {
        return !predicate.apply(this, arguments);
      };
    }

    /**
     * Creates a function that is restricted to invoking `func` once. Repeat calls
     * to the function return the value of the first call. The `func` is invoked
     * with the `this` binding and arguments of the created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * var initialize = _.once(createApplication);
     * initialize();
     * initialize();
     * // `initialize` invokes `createApplication` once
     */
    function once(func) {
      return before(2, func);
    }

    /**
     * Creates a function that invokes `func` with `partial` arguments prepended
     * to those provided to the new function. This method is like `_.bind` except
     * it does **not** alter the `this` binding.
     *
     * The `_.partial.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for partially applied arguments.
     *
     * **Note:** This method does not set the "length" property of partially
     * applied functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to partially apply arguments to.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new partially applied function.
     * @example
     *
     * var greet = function(greeting, name) {
     *   return greeting + ' ' + name;
     * };
     *
     * var sayHelloTo = _.partial(greet, 'hello');
     * sayHelloTo('fred');
     * // => 'hello fred'
     *
     * // using placeholders
     * var greetFred = _.partial(greet, _, 'fred');
     * greetFred('hi');
     * // => 'hi fred'
     */
    var partial = createPartial(PARTIAL_FLAG);

    /**
     * This method is like `_.partial` except that partially applied arguments
     * are appended to those provided to the new function.
     *
     * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
     * builds, may be used as a placeholder for partially applied arguments.
     *
     * **Note:** This method does not set the "length" property of partially
     * applied functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to partially apply arguments to.
     * @param {...*} [partials] The arguments to be partially applied.
     * @returns {Function} Returns the new partially applied function.
     * @example
     *
     * var greet = function(greeting, name) {
     *   return greeting + ' ' + name;
     * };
     *
     * var greetFred = _.partialRight(greet, 'fred');
     * greetFred('hi');
     * // => 'hi fred'
     *
     * // using placeholders
     * var sayHelloTo = _.partialRight(greet, 'hello', _);
     * sayHelloTo('fred');
     * // => 'hello fred'
     */
    var partialRight = createPartial(PARTIAL_RIGHT_FLAG);

    /**
     * Creates a function that invokes `func` with arguments arranged according
     * to the specified indexes where the argument value at the first index is
     * provided as the first argument, the argument value at the second index is
     * provided as the second argument, and so on.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to rearrange arguments for.
     * @param {...(number|number[])} indexes The arranged argument indexes,
     *  specified as individual indexes or arrays of indexes.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var rearged = _.rearg(function(a, b, c) {
     *   return [a, b, c];
     * }, 2, 0, 1);
     *
     * rearged('b', 'c', 'a')
     * // => ['a', 'b', 'c']
     *
     * var map = _.rearg(_.map, [1, 0]);
     * map(function(n) {
     *   return n * 3;
     * }, [1, 2, 3]);
     * // => [3, 6, 9]
     */
    var rearg = restParam(function(func, indexes) {
      return createWrapper(func, REARG_FLAG, null, null, null, baseFlatten(indexes));
    });

    /**
     * Creates a function that invokes `func` with the `this` binding of the
     * created function and arguments from `start` and beyond provided as an array.
     *
     * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters).
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to apply a rest parameter to.
     * @param {number} [start=func.length-1] The start position of the rest parameter.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var say = _.restParam(function(what, names) {
     *   return what + ' ' + _.initial(names).join(', ') +
     *     (_.size(names) > 1 ? ', & ' : '') + _.last(names);
     * });
     *
     * say('hello', 'fred', 'barney', 'pebbles');
     * // => 'hello fred, barney, & pebbles'
     */
    function restParam(func, start) {
      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
      return function() {
        var args = arguments,
            index = -1,
            length = nativeMax(args.length - start, 0),
            rest = Array(length);

        while (++index < length) {
          rest[index] = args[start + index];
        }
        switch (start) {
          case 0: return func.call(this, rest);
          case 1: return func.call(this, args[0], rest);
          case 2: return func.call(this, args[0], args[1], rest);
        }
        var otherArgs = Array(start + 1);
        index = -1;
        while (++index < start) {
          otherArgs[index] = args[index];
        }
        otherArgs[start] = rest;
        return func.apply(this, otherArgs);
      };
    }

    /**
     * Creates a function that invokes `func` with the `this` binding of the created
     * function and an array of arguments much like [`Function#apply`](https://es5.github.io/#x15.3.4.3).
     *
     * **Note:** This method is based on the [spread operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator).
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to spread arguments over.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var say = _.spread(function(who, what) {
     *   return who + ' says ' + what;
     * });
     *
     * say(['fred', 'hello']);
     * // => 'fred says hello'
     *
     * // with a Promise
     * var numbers = Promise.all([
     *   Promise.resolve(40),
     *   Promise.resolve(36)
     * ]);
     *
     * numbers.then(_.spread(function(x, y) {
     *   return x + y;
     * }));
     * // => a Promise of 76
     */
    function spread(func) {
      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function(array) {
        return func.apply(this, array);
      };
    }

    /**
     * Creates a function that only invokes `func` at most once per every `wait`
     * milliseconds. The created function comes with a `cancel` method to cancel
     * delayed invocations. Provide an options object to indicate that `func`
     * should be invoked on the leading and/or trailing edge of the `wait` timeout.
     * Subsequent calls to the throttled function return the result of the last
     * `func` call.
     *
     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
     * on the trailing edge of the timeout only if the the throttled function is
     * invoked more than once during the `wait` timeout.
     *
     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
     * for details over the differences between `_.throttle` and `_.debounce`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to throttle.
     * @param {number} [wait=0] The number of milliseconds to throttle invocations to.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.leading=true] Specify invoking on the leading
     *  edge of the timeout.
     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
     *  edge of the timeout.
     * @returns {Function} Returns the new throttled function.
     * @example
     *
     * // avoid excessively updating the position while scrolling
     * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
     *
     * // invoke `renewToken` when the click event is fired, but not more than once every 5 minutes
     * jQuery('.interactive').on('click', _.throttle(renewToken, 300000, {
     *   'trailing': false
     * }));
     *
     * // cancel a trailing throttled call
     * jQuery(window).on('popstate', throttled.cancel);
     */
    function throttle(func, wait, options) {
      var leading = true,
          trailing = true;

      if (typeof func != 'function') {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      if (options === false) {
        leading = false;
      } else if (isObject(options)) {
        leading = 'leading' in options ? !!options.leading : leading;
        trailing = 'trailing' in options ? !!options.trailing : trailing;
      }
      debounceOptions.leading = leading;
      debounceOptions.maxWait = +wait;
      debounceOptions.trailing = trailing;
      return debounce(func, wait, debounceOptions);
    }

    /**
     * Creates a function that provides `value` to the wrapper function as its
     * first argument. Any additional arguments provided to the function are
     * appended to those provided to the wrapper function. The wrapper is invoked
     * with the `this` binding of the created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {*} value The value to wrap.
     * @param {Function} wrapper The wrapper function.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var p = _.wrap(_.escape, function(func, text) {
     *   return '<p>' + func(text) + '</p>';
     * });
     *
     * p('fred, barney, & pebbles');
     * // => '<p>fred, barney, &amp; pebbles</p>'
     */
    function wrap(value, wrapper) {
      wrapper = wrapper == null ? identity : wrapper;
      return createWrapper(wrapper, PARTIAL_FLAG, null, [value], []);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a clone of `value`. If `isDeep` is `true` nested objects are cloned,
     * otherwise they are assigned by reference. If `customizer` is provided it is
     * invoked to produce the cloned values. If `customizer` returns `undefined`
     * cloning is handled by the method instead. The `customizer` is bound to
     * `thisArg` and invoked with two argument; (value [, index|key, object]).
     *
     * **Note:** This method is loosely based on the
     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
     * The enumerable properties of `arguments` objects and objects created by
     * constructors other than `Object` are cloned to plain `Object` objects. An
     * empty object is returned for uncloneable values such as functions, DOM nodes,
     * Maps, Sets, and WeakMaps.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep] Specify a deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {*} Returns the cloned value.
     * @example
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * var shallow = _.clone(users);
     * shallow[0] === users[0];
     * // => true
     *
     * var deep = _.clone(users, true);
     * deep[0] === users[0];
     * // => false
     *
     * // using a customizer callback
     * var el = _.clone(document.body, function(value) {
     *   if (_.isElement(value)) {
     *     return value.cloneNode(false);
     *   }
     * });
     *
     * el === document.body
     * // => false
     * el.nodeName
     * // => BODY
     * el.childNodes.length;
     * // => 0
     */
    function clone(value, isDeep, customizer, thisArg) {
      if (isDeep && typeof isDeep != 'boolean' && isIterateeCall(value, isDeep, customizer)) {
        isDeep = false;
      }
      else if (typeof isDeep == 'function') {
        thisArg = customizer;
        customizer = isDeep;
        isDeep = false;
      }
      customizer = typeof customizer == 'function' && bindCallback(customizer, thisArg, 1);
      return baseClone(value, isDeep, customizer);
    }

    /**
     * Creates a deep clone of `value`. If `customizer` is provided it is invoked
     * to produce the cloned values. If `customizer` returns `undefined` cloning
     * is handled by the method instead. The `customizer` is bound to `thisArg`
     * and invoked with two argument; (value [, index|key, object]).
     *
     * **Note:** This method is loosely based on the
     * [structured clone algorithm](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm).
     * The enumerable properties of `arguments` objects and objects created by
     * constructors other than `Object` are cloned to plain `Object` objects. An
     * empty object is returned for uncloneable values such as functions, DOM nodes,
     * Maps, Sets, and WeakMaps.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {*} Returns the deep cloned value.
     * @example
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * var deep = _.cloneDeep(users);
     * deep[0] === users[0];
     * // => false
     *
     * // using a customizer callback
     * var el = _.cloneDeep(document.body, function(value) {
     *   if (_.isElement(value)) {
     *     return value.cloneNode(true);
     *   }
     * });
     *
     * el === document.body
     * // => false
     * el.nodeName
     * // => BODY
     * el.childNodes.length;
     * // => 20
     */
    function cloneDeep(value, customizer, thisArg) {
      customizer = typeof customizer == 'function' && bindCallback(customizer, thisArg, 1);
      return baseClone(value, true, customizer);
    }

    /**
     * Checks if `value` is classified as an `arguments` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isArguments(function() { return arguments; }());
     * // => true
     *
     * _.isArguments([1, 2, 3]);
     * // => false
     */
    function isArguments(value) {
      var length = isObjectLike(value) ? value.length : undefined;
      return isLength(length) && objToString.call(value) == argsTag;
    }

    /**
     * Checks if `value` is classified as an `Array` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isArray([1, 2, 3]);
     * // => true
     *
     * _.isArray(function() { return arguments; }());
     * // => false
     */
    var isArray = nativeIsArray || function(value) {
      return isObjectLike(value) && isLength(value.length) && objToString.call(value) == arrayTag;
    };

    /**
     * Checks if `value` is classified as a boolean primitive or object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isBoolean(false);
     * // => true
     *
     * _.isBoolean(null);
     * // => false
     */
    function isBoolean(value) {
      return value === true || value === false || (isObjectLike(value) && objToString.call(value) == boolTag);
    }

    /**
     * Checks if `value` is classified as a `Date` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isDate(new Date);
     * // => true
     *
     * _.isDate('Mon April 23 2012');
     * // => false
     */
    function isDate(value) {
      return isObjectLike(value) && objToString.call(value) == dateTag;
    }

    /**
     * Checks if `value` is a DOM element.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.
     * @example
     *
     * _.isElement(document.body);
     * // => true
     *
     * _.isElement('<body>');
     * // => false
     */
    function isElement(value) {
      return !!value && value.nodeType === 1 && isObjectLike(value) &&
        (objToString.call(value).indexOf('Element') > -1);
    }
    // Fallback for environments without DOM support.
    if (!support.dom) {
      isElement = function(value) {
        return !!value && value.nodeType === 1 && isObjectLike(value) && !isPlainObject(value);
      };
    }

    /**
     * Checks if `value` is empty. A value is considered empty unless it is an
     * `arguments` object, array, string, or jQuery-like collection with a length
     * greater than `0` or an object with own enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {Array|Object|string} value The value to inspect.
     * @returns {boolean} Returns `true` if `value` is empty, else `false`.
     * @example
     *
     * _.isEmpty(null);
     * // => true
     *
     * _.isEmpty(true);
     * // => true
     *
     * _.isEmpty(1);
     * // => true
     *
     * _.isEmpty([1, 2, 3]);
     * // => false
     *
     * _.isEmpty({ 'a': 1 });
     * // => false
     */
    function isEmpty(value) {
      if (value == null) {
        return true;
      }
      var length = getLength(value);
      if (isLength(length) && (isArray(value) || isString(value) || isArguments(value) ||
          (isObjectLike(value) && isFunction(value.splice)))) {
        return !length;
      }
      return !keys(value).length;
    }

    /**
     * Performs a deep comparison between two values to determine if they are
     * equivalent. If `customizer` is provided it is invoked to compare values.
     * If `customizer` returns `undefined` comparisons are handled by the method
     * instead. The `customizer` is bound to `thisArg` and invoked with three
     * arguments: (value, other [, index|key]).
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. Functions and DOM nodes
     * are **not** supported. Provide a customizer function to extend support
     * for comparing other values.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to compare.
     * @param {*} other The other value to compare.
     * @param {Function} [customizer] The function to customize value comparisons.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
     * @example
     *
     * var object = { 'user': 'fred' };
     * var other = { 'user': 'fred' };
     *
     * object == other;
     * // => false
     *
     * _.isEqual(object, other);
     * // => true
     *
     * // using a customizer callback
     * var array = ['hello', 'goodbye'];
     * var other = ['hi', 'goodbye'];
     *
     * _.isEqual(array, other, function(value, other) {
     *   if (_.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/)) {
     *     return true;
     *   }
     * });
     * // => true
     */
    function isEqual(value, other, customizer, thisArg) {
      customizer = typeof customizer == 'function' && bindCallback(customizer, thisArg, 3);
      if (!customizer && isStrictComparable(value) && isStrictComparable(other)) {
        return value === other;
      }
      var result = customizer ? customizer(value, other) : undefined;
      return result === undefined ? baseIsEqual(value, other, customizer) : !!result;
    }

    /**
     * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
     * `SyntaxError`, `TypeError`, or `URIError` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
     * @example
     *
     * _.isError(new Error);
     * // => true
     *
     * _.isError(Error);
     * // => false
     */
    function isError(value) {
      return isObjectLike(value) && typeof value.message == 'string' && objToString.call(value) == errorTag;
    }

    /**
     * Checks if `value` is a finite primitive number.
     *
     * **Note:** This method is based on [`Number.isFinite`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.isfinite).
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.
     * @example
     *
     * _.isFinite(10);
     * // => true
     *
     * _.isFinite('10');
     * // => false
     *
     * _.isFinite(true);
     * // => false
     *
     * _.isFinite(Object(10));
     * // => false
     *
     * _.isFinite(Infinity);
     * // => false
     */
    var isFinite = nativeNumIsFinite || function(value) {
      return typeof value == 'number' && nativeIsFinite(value);
    };

    /**
     * Checks if `value` is classified as a `Function` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isFunction(_);
     * // => true
     *
     * _.isFunction(/abc/);
     * // => false
     */
    var isFunction = !(baseIsFunction(/x/) || (Uint8Array && !baseIsFunction(Uint8Array))) ? baseIsFunction : function(value) {
      // The use of `Object#toString` avoids issues with the `typeof` operator
      // in older versions of Chrome and Safari which return 'function' for regexes
      // and Safari 8 equivalents which return 'object' for typed array constructors.
      return objToString.call(value) == funcTag;
    };

    /**
     * Checks if `value` is the [language type](https://es5.github.io/#x8) of `Object`.
     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an object, else `false`.
     * @example
     *
     * _.isObject({});
     * // => true
     *
     * _.isObject([1, 2, 3]);
     * // => true
     *
     * _.isObject(1);
     * // => false
     */
    function isObject(value) {
      // Avoid a V8 JIT bug in Chrome 19-20.
      // See https://code.google.com/p/v8/issues/detail?id=2291 for more details.
      var type = typeof value;
      return type == 'function' || (!!value && type == 'object');
    }

    /**
     * Performs a deep comparison between `object` and `source` to determine if
     * `object` contains equivalent property values. If `customizer` is provided
     * it is invoked to compare values. If `customizer` returns `undefined`
     * comparisons are handled by the method instead. The `customizer` is bound
     * to `thisArg` and invoked with three arguments: (value, other, index|key).
     *
     * **Note:** This method supports comparing properties of arrays, booleans,
     * `Date` objects, numbers, `Object` objects, regexes, and strings. Functions
     * and DOM nodes are **not** supported. Provide a customizer function to extend
     * support for comparing other values.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {Object} object The object to inspect.
     * @param {Object} source The object of property values to match.
     * @param {Function} [customizer] The function to customize value comparisons.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {boolean} Returns `true` if `object` is a match, else `false`.
     * @example
     *
     * var object = { 'user': 'fred', 'age': 40 };
     *
     * _.isMatch(object, { 'age': 40 });
     * // => true
     *
     * _.isMatch(object, { 'age': 36 });
     * // => false
     *
     * // using a customizer callback
     * var object = { 'greeting': 'hello' };
     * var source = { 'greeting': 'hi' };
     *
     * _.isMatch(object, source, function(value, other) {
     *   return _.every([value, other], RegExp.prototype.test, /^h(?:i|ello)$/) || undefined;
     * });
     * // => true
     */
    function isMatch(object, source, customizer, thisArg) {
      var props = keys(source),
          length = props.length;

      if (!length) {
        return true;
      }
      if (object == null) {
        return false;
      }
      customizer = typeof customizer == 'function' && bindCallback(customizer, thisArg, 3);
      object = toObject(object);
      if (!customizer && length == 1) {
        var key = props[0],
            value = source[key];

        if (isStrictComparable(value)) {
          return value === object[key] && (value !== undefined || (key in object));
        }
      }
      var values = Array(length),
          strictCompareFlags = Array(length);

      while (length--) {
        value = values[length] = source[props[length]];
        strictCompareFlags[length] = isStrictComparable(value);
      }
      return baseIsMatch(object, props, values, strictCompareFlags, customizer);
    }

    /**
     * Checks if `value` is `NaN`.
     *
     * **Note:** This method is not the same as [`isNaN`](https://es5.github.io/#x15.1.2.4)
     * which returns `true` for `undefined` and other non-numeric values.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
     * @example
     *
     * _.isNaN(NaN);
     * // => true
     *
     * _.isNaN(new Number(NaN));
     * // => true
     *
     * isNaN(undefined);
     * // => true
     *
     * _.isNaN(undefined);
     * // => false
     */
    function isNaN(value) {
      // An `NaN` primitive is the only value that is not equal to itself.
      // Perform the `toStringTag` check first to avoid errors with some host objects in IE.
      return isNumber(value) && value != +value;
    }

    /**
     * Checks if `value` is a native function.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
     * @example
     *
     * _.isNative(Array.prototype.push);
     * // => true
     *
     * _.isNative(_);
     * // => false
     */
    function isNative(value) {
      if (value == null) {
        return false;
      }
      if (objToString.call(value) == funcTag) {
        return reIsNative.test(fnToString.call(value));
      }
      return isObjectLike(value) && reIsHostCtor.test(value);
    }

    /**
     * Checks if `value` is `null`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `null`, else `false`.
     * @example
     *
     * _.isNull(null);
     * // => true
     *
     * _.isNull(void 0);
     * // => false
     */
    function isNull(value) {
      return value === null;
    }

    /**
     * Checks if `value` is classified as a `Number` primitive or object.
     *
     * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are classified
     * as numbers, use the `_.isFinite` method.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isNumber(8.4);
     * // => true
     *
     * _.isNumber(NaN);
     * // => true
     *
     * _.isNumber('8.4');
     * // => false
     */
    function isNumber(value) {
      return typeof value == 'number' || (isObjectLike(value) && objToString.call(value) == numberTag);
    }

    /**
     * Checks if `value` is a plain object, that is, an object created by the
     * `Object` constructor or one with a `[[Prototype]]` of `null`.
     *
     * **Note:** This method assumes objects created by the `Object` constructor
     * have no inherited enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     * }
     *
     * _.isPlainObject(new Foo);
     * // => false
     *
     * _.isPlainObject([1, 2, 3]);
     * // => false
     *
     * _.isPlainObject({ 'x': 0, 'y': 0 });
     * // => true
     *
     * _.isPlainObject(Object.create(null));
     * // => true
     */
    var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
      if (!(value && objToString.call(value) == objectTag)) {
        return false;
      }
      var valueOf = value.valueOf,
          objProto = isNative(valueOf) && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);

      return objProto
        ? (value == objProto || getPrototypeOf(value) == objProto)
        : shimIsPlainObject(value);
    };

    /**
     * Checks if `value` is classified as a `RegExp` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isRegExp(/abc/);
     * // => true
     *
     * _.isRegExp('/abc/');
     * // => false
     */
    function isRegExp(value) {
      return (isObjectLike(value) && objToString.call(value) == regexpTag) || false;
    }

    /**
     * Checks if `value` is classified as a `String` primitive or object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isString('abc');
     * // => true
     *
     * _.isString(1);
     * // => false
     */
    function isString(value) {
      return typeof value == 'string' || (isObjectLike(value) && objToString.call(value) == stringTag);
    }

    /**
     * Checks if `value` is classified as a typed array.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isTypedArray(new Uint8Array);
     * // => true
     *
     * _.isTypedArray([]);
     * // => false
     */
    function isTypedArray(value) {
      return isObjectLike(value) && isLength(value.length) && !!typedArrayTags[objToString.call(value)];
    }

    /**
     * Checks if `value` is `undefined`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.
     * @example
     *
     * _.isUndefined(void 0);
     * // => true
     *
     * _.isUndefined(null);
     * // => false
     */
    function isUndefined(value) {
      return value === undefined;
    }

    /**
     * Converts `value` to an array.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to convert.
     * @returns {Array} Returns the converted array.
     * @example
     *
     * (function() {
     *   return _.toArray(arguments).slice(1);
     * }(1, 2, 3));
     * // => [2, 3]
     */
    function toArray(value) {
      var length = value ? getLength(value) : 0;
      if (!isLength(length)) {
        return values(value);
      }
      if (!length) {
        return [];
      }
      return arrayCopy(value);
    }

    /**
     * Converts `value` to a plain object flattening inherited enumerable
     * properties of `value` to own properties of the plain object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to convert.
     * @returns {Object} Returns the converted plain object.
     * @example
     *
     * function Foo() {
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.assign({ 'a': 1 }, new Foo);
     * // => { 'a': 1, 'b': 2 }
     *
     * _.assign({ 'a': 1 }, _.toPlainObject(new Foo));
     * // => { 'a': 1, 'b': 2, 'c': 3 }
     */
    function toPlainObject(value) {
      return baseCopy(value, keysIn(value));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Assigns own enumerable properties of source object(s) to the destination
     * object. Subsequent sources overwrite property assignments of previous sources.
     * If `customizer` is provided it is invoked to produce the assigned values.
     * The `customizer` is bound to `thisArg` and invoked with five arguments:
     * (objectValue, sourceValue, key, object, source).
     *
     * **Note:** This method mutates `object` and is based on
     * [`Object.assign`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.assign).
     *
     *
     * @static
     * @memberOf _
     * @alias extend
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @param {Function} [customizer] The function to customize assigned values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * _.assign({ 'user': 'barney' }, { 'age': 40 }, { 'user': 'fred' });
     * // => { 'user': 'fred', 'age': 40 }
     *
     * // using a customizer callback
     * var defaults = _.partialRight(_.assign, function(value, other) {
     *   return _.isUndefined(value) ? other : value;
     * });
     *
     * defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
     * // => { 'user': 'barney', 'age': 36 }
     */
    var assign = createAssigner(function(object, source, customizer) {
      return customizer
        ? assignWith(object, source, customizer)
        : baseAssign(object, source);
    });

    /**
     * Creates an object that inherits from the given `prototype` object. If a
     * `properties` object is provided its own enumerable properties are assigned
     * to the created object.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} prototype The object to inherit from.
     * @param {Object} [properties] The properties to assign to the object.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * function Circle() {
     *   Shape.call(this);
     * }
     *
     * Circle.prototype = _.create(Shape.prototype, {
     *   'constructor': Circle
     * });
     *
     * var circle = new Circle;
     * circle instanceof Circle;
     * // => true
     *
     * circle instanceof Shape;
     * // => true
     */
    function create(prototype, properties, guard) {
      var result = baseCreate(prototype);
      if (guard && isIterateeCall(prototype, properties, guard)) {
        properties = null;
      }
      return properties ? baseAssign(result, properties) : result;
    }

    /**
     * Assigns own enumerable properties of source object(s) to the destination
     * object for all destination properties that resolve to `undefined`. Once a
     * property is set, additional values of the same property are ignored.
     *
     * **Note:** This method mutates `object`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @returns {Object} Returns `object`.
     * @example
     *
     * _.defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
     * // => { 'user': 'barney', 'age': 36 }
     */
    var defaults = restParam(function(args) {
      var object = args[0];
      if (object == null) {
        return object;
      }
      args.push(assignDefaults);
      return assign.apply(undefined, args);
    });

    /**
     * This method is like `_.find` except that it returns the key of the first
     * element `predicate` returns truthy for instead of the element itself.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
     * @example
     *
     * var users = {
     *   'barney':  { 'age': 36, 'active': true },
     *   'fred':    { 'age': 40, 'active': false },
     *   'pebbles': { 'age': 1,  'active': true }
     * };
     *
     * _.findKey(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => 'barney' (iteration order is not guaranteed)
     *
     * // using the `_.matches` callback shorthand
     * _.findKey(users, { 'age': 1, 'active': true });
     * // => 'pebbles'
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findKey(users, 'active', false);
     * // => 'fred'
     *
     * // using the `_.property` callback shorthand
     * _.findKey(users, 'active');
     * // => 'barney'
     */
    var findKey = createFindKey(baseForOwn);

    /**
     * This method is like `_.findKey` except that it iterates over elements of
     * a collection in the opposite order.
     *
     * If a property name is provided for `predicate` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `predicate` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to search.
     * @param {Function|Object|string} [predicate=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
     * @example
     *
     * var users = {
     *   'barney':  { 'age': 36, 'active': true },
     *   'fred':    { 'age': 40, 'active': false },
     *   'pebbles': { 'age': 1,  'active': true }
     * };
     *
     * _.findLastKey(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => returns `pebbles` assuming `_.findKey` returns `barney`
     *
     * // using the `_.matches` callback shorthand
     * _.findLastKey(users, { 'age': 36, 'active': true });
     * // => 'barney'
     *
     * // using the `_.matchesProperty` callback shorthand
     * _.findLastKey(users, 'active', false);
     * // => 'fred'
     *
     * // using the `_.property` callback shorthand
     * _.findLastKey(users, 'active');
     * // => 'pebbles'
     */
    var findLastKey = createFindKey(baseForOwnRight);

    /**
     * Iterates over own and inherited enumerable properties of an object invoking
     * `iteratee` for each property. The `iteratee` is bound to `thisArg` and invoked
     * with three arguments: (value, key, object). Iteratee functions may exit
     * iteration early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forIn(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'a', 'b', and 'c' (iteration order is not guaranteed)
     */
    var forIn = createForIn(baseFor);

    /**
     * This method is like `_.forIn` except that it iterates over properties of
     * `object` in the opposite order.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forInRight(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'c', 'b', and 'a' assuming `_.forIn ` logs 'a', 'b', and 'c'
     */
    var forInRight = createForIn(baseForRight);

    /**
     * Iterates over own enumerable properties of an object invoking `iteratee`
     * for each property. The `iteratee` is bound to `thisArg` and invoked with
     * three arguments: (value, key, object). Iteratee functions may exit iteration
     * early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forOwn(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'a' and 'b' (iteration order is not guaranteed)
     */
    var forOwn = createForOwn(baseForOwn);

    /**
     * This method is like `_.forOwn` except that it iterates over properties of
     * `object` in the opposite order.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.forOwnRight(new Foo, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'b' and 'a' assuming `_.forOwn` logs 'a' and 'b'
     */
    var forOwnRight = createForOwn(baseForOwnRight);

    /**
     * Creates an array of function property names from all enumerable properties,
     * own and inherited, of `object`.
     *
     * @static
     * @memberOf _
     * @alias methods
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the new array of property names.
     * @example
     *
     * _.functions(_);
     * // => ['after', 'ary', 'assign', ...]
     */
    function functions(object) {
      return baseFunctions(object, keysIn(object));
    }

    /**
     * Gets the property value of `path` on `object`. If the resolved value is
     * `undefined` the `defaultValue` is used in its place.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @param {Array|string} path The path of the property to get.
     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
     * @returns {*} Returns the resolved value.
     * @example
     *
     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
     *
     * _.get(object, 'a[0].b.c');
     * // => 3
     *
     * _.get(object, ['a', '0', 'b', 'c']);
     * // => 3
     *
     * _.get(object, 'a.b.c', 'default');
     * // => 'default'
     */
    function get(object, path, defaultValue) {
      var result = object == null ? undefined : baseGet(object, toPath(path), path + '');
      return result === undefined ? defaultValue : result;
    }

    /**
     * Checks if `path` is a direct property.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @param {Array|string} path The path to check.
     * @returns {boolean} Returns `true` if `path` is a direct property, else `false`.
     * @example
     *
     * var object = { 'a': { 'b': { 'c': 3 } } };
     *
     * _.has(object, 'a');
     * // => true
     *
     * _.has(object, 'a.b.c');
     * // => true
     *
     * _.has(object, ['a', 'b', 'c']);
     * // => true
     */
    function has(object, path) {
      if (object == null) {
        return false;
      }
      var result = hasOwnProperty.call(object, path);
      if (!result && !isKey(path)) {
        path = toPath(path);
        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
        path = last(path);
        result = object != null && hasOwnProperty.call(object, path);
      }
      return result;
    }

    /**
     * Creates an object composed of the inverted keys and values of `object`.
     * If `object` contains duplicate values, subsequent values overwrite property
     * assignments of previous values unless `multiValue` is `true`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to invert.
     * @param {boolean} [multiValue] Allow multiple values per key.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Object} Returns the new inverted object.
     * @example
     *
     * var object = { 'a': 1, 'b': 2, 'c': 1 };
     *
     * _.invert(object);
     * // => { '1': 'c', '2': 'b' }
     *
     * // with `multiValue`
     * _.invert(object, true);
     * // => { '1': ['a', 'c'], '2': ['b'] }
     */
    function invert(object, multiValue, guard) {
      if (guard && isIterateeCall(object, multiValue, guard)) {
        multiValue = null;
      }
      var index = -1,
          props = keys(object),
          length = props.length,
          result = {};

      while (++index < length) {
        var key = props[index],
            value = object[key];

        if (multiValue) {
          if (hasOwnProperty.call(result, value)) {
            result[value].push(key);
          } else {
            result[value] = [key];
          }
        }
        else {
          result[value] = key;
        }
      }
      return result;
    }

    /**
     * Creates an array of the own enumerable property names of `object`.
     *
     * **Note:** Non-object values are coerced to objects. See the
     * [ES spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.keys)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property names.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.keys(new Foo);
     * // => ['a', 'b'] (iteration order is not guaranteed)
     *
     * _.keys('hi');
     * // => ['0', '1']
     */
    var keys = !nativeKeys ? shimKeys : function(object) {
      if (object) {
        var Ctor = object.constructor,
            length = object.length;
      }
      if ((typeof Ctor == 'function' && Ctor.prototype === object) ||
          (typeof object != 'function' && isLength(length))) {
        return shimKeys(object);
      }
      return isObject(object) ? nativeKeys(object) : [];
    };

    /**
     * Creates an array of the own and inherited enumerable property names of `object`.
     *
     * **Note:** Non-object values are coerced to objects.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property names.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.keysIn(new Foo);
     * // => ['a', 'b', 'c'] (iteration order is not guaranteed)
     */
    function keysIn(object) {
      if (object == null) {
        return [];
      }
      if (!isObject(object)) {
        object = Object(object);
      }
      var length = object.length;
      length = (length && isLength(length) &&
        (isArray(object) || (support.nonEnumArgs && isArguments(object))) && length) || 0;

      var Ctor = object.constructor,
          index = -1,
          isProto = typeof Ctor == 'function' && Ctor.prototype === object,
          result = Array(length),
          skipIndexes = length > 0;

      while (++index < length) {
        result[index] = (index + '');
      }
      for (var key in object) {
        if (!(skipIndexes && isIndex(key, length)) &&
            !(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
          result.push(key);
        }
      }
      return result;
    }

    /**
     * Creates an object with the same keys as `object` and values generated by
     * running each own enumerable property of `object` through `iteratee`. The
     * iteratee function is bound to `thisArg` and invoked with three arguments:
     * (value, key, object).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function|Object|string} [iteratee=_.identity] The function invoked
     *  per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the new mapped object.
     * @example
     *
     * _.mapValues({ 'a': 1, 'b': 2 }, function(n) {
     *   return n * 3;
     * });
     * // => { 'a': 3, 'b': 6 }
     *
     * var users = {
     *   'fred':    { 'user': 'fred',    'age': 40 },
     *   'pebbles': { 'user': 'pebbles', 'age': 1 }
     * };
     *
     * // using the `_.property` callback shorthand
     * _.mapValues(users, 'age');
     * // => { 'fred': 40, 'pebbles': 1 } (iteration order is not guaranteed)
     */
    function mapValues(object, iteratee, thisArg) {
      var result = {};
      iteratee = getCallback(iteratee, thisArg, 3);

      baseForOwn(object, function(value, key, object) {
        result[key] = iteratee(value, key, object);
      });
      return result;
    }

    /**
     * Recursively merges own enumerable properties of the source object(s), that
     * don't resolve to `undefined` into the destination object. Subsequent sources
     * overwrite property assignments of previous sources. If `customizer` is
     * provided it is invoked to produce the merged values of the destination and
     * source properties. If `customizer` returns `undefined` merging is handled
     * by the method instead. The `customizer` is bound to `thisArg` and invoked
     * with five arguments: (objectValue, sourceValue, key, object, source).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @param {Function} [customizer] The function to customize assigned values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var users = {
     *   'data': [{ 'user': 'barney' }, { 'user': 'fred' }]
     * };
     *
     * var ages = {
     *   'data': [{ 'age': 36 }, { 'age': 40 }]
     * };
     *
     * _.merge(users, ages);
     * // => { 'data': [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred', 'age': 40 }] }
     *
     * // using a customizer callback
     * var object = {
     *   'fruits': ['apple'],
     *   'vegetables': ['beet']
     * };
     *
     * var other = {
     *   'fruits': ['banana'],
     *   'vegetables': ['carrot']
     * };
     *
     * _.merge(object, other, function(a, b) {
     *   if (_.isArray(a)) {
     *     return a.concat(b);
     *   }
     * });
     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot'] }
     */
    var merge = createAssigner(baseMerge);

    /**
     * The opposite of `_.pick`; this method creates an object composed of the
     * own and inherited enumerable properties of `object` that are not omitted.
     * Property names may be specified as individual arguments or as arrays of
     * property names. If `predicate` is provided it is invoked for each property
     * of `object` omitting the properties `predicate` returns truthy for. The
     * predicate is bound to `thisArg` and invoked with three arguments:
     * (value, key, object).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The source object.
     * @param {Function|...(string|string[])} [predicate] The function invoked per
     *  iteration or property names to omit, specified as individual property
     *  names or arrays of property names.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * var object = { 'user': 'fred', 'age': 40 };
     *
     * _.omit(object, 'age');
     * // => { 'user': 'fred' }
     *
     * _.omit(object, _.isNumber);
     * // => { 'user': 'fred' }
     */
    var omit = restParam(function(object, props) {
      if (object == null) {
        return {};
      }
      if (typeof props[0] != 'function') {
        var props = arrayMap(baseFlatten(props), String);
        return pickByArray(object, baseDifference(keysIn(object), props));
      }
      var predicate = bindCallback(props[0], props[1], 3);
      return pickByCallback(object, function(value, key, object) {
        return !predicate(value, key, object);
      });
    });

    /**
     * Creates a two dimensional array of the key-value pairs for `object`,
     * e.g. `[[key1, value1], [key2, value2]]`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the new array of key-value pairs.
     * @example
     *
     * _.pairs({ 'barney': 36, 'fred': 40 });
     * // => [['barney', 36], ['fred', 40]] (iteration order is not guaranteed)
     */
    function pairs(object) {
      var index = -1,
          props = keys(object),
          length = props.length,
          result = Array(length);

      while (++index < length) {
        var key = props[index];
        result[index] = [key, object[key]];
      }
      return result;
    }

    /**
     * Creates an object composed of the picked `object` properties. Property
     * names may be specified as individual arguments or as arrays of property
     * names. If `predicate` is provided it is invoked for each property of `object`
     * picking the properties `predicate` returns truthy for. The predicate is
     * bound to `thisArg` and invoked with three arguments: (value, key, object).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The source object.
     * @param {Function|...(string|string[])} [predicate] The function invoked per
     *  iteration or property names to pick, specified as individual property
     *  names or arrays of property names.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * var object = { 'user': 'fred', 'age': 40 };
     *
     * _.pick(object, 'user');
     * // => { 'user': 'fred' }
     *
     * _.pick(object, _.isString);
     * // => { 'user': 'fred' }
     */
    var pick = restParam(function(object, props) {
      if (object == null) {
        return {};
      }
      return typeof props[0] == 'function'
        ? pickByCallback(object, bindCallback(props[0], props[1], 3))
        : pickByArray(object, baseFlatten(props));
    });

    /**
     * This method is like `_.get` except that if the resolved value is a function
     * it is invoked with the `this` binding of its parent object and its result
     * is returned.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @param {Array|string} path The path of the property to resolve.
     * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
     * @returns {*} Returns the resolved value.
     * @example
     *
     * var object = { 'a': [{ 'b': { 'c1': 3, 'c2': _.constant(4) } }] };
     *
     * _.result(object, 'a[0].b.c1');
     * // => 3
     *
     * _.result(object, 'a[0].b.c2');
     * // => 4
     *
     * _.result(object, 'a.b.c', 'default');
     * // => 'default'
     *
     * _.result(object, 'a.b.c', _.constant('default'));
     * // => 'default'
     */
    function result(object, path, defaultValue) {
      var result = object == null ? undefined : object[path];
      if (result === undefined) {
        if (object != null && !isKey(path, object)) {
          path = toPath(path);
          object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
          result = object == null ? undefined : object[last(path)];
        }
        result = result === undefined ? defaultValue : result;
      }
      return isFunction(result) ? result.call(object) : result;
    }

    /**
     * Sets the property value of `path` on `object`. If a portion of `path`
     * does not exist it is created.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to augment.
     * @param {Array|string} path The path of the property to set.
     * @param {*} value The value to set.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var object = { 'a': [{ 'b': { 'c': 3 } }] };
     *
     * _.set(object, 'a[0].b.c', 4);
     * console.log(object.a[0].b.c);
     * // => 4
     *
     * _.set(object, 'x[0].y.z', 5);
     * console.log(object.x[0].y.z);
     * // => 5
     */
    function set(object, path, value) {
      if (object == null) {
        return object;
      }
      var pathKey = (path + '');
      path = (object[pathKey] != null || isKey(path, object)) ? [pathKey] : toPath(path);

      var index = -1,
          length = path.length,
          endIndex = length - 1,
          nested = object;

      while (nested != null && ++index < length) {
        var key = path[index];
        if (isObject(nested)) {
          if (index == endIndex) {
            nested[key] = value;
          } else if (nested[key] == null) {
            nested[key] = isIndex(path[index + 1]) ? [] : {};
          }
        }
        nested = nested[key];
      }
      return object;
    }

    /**
     * An alternative to `_.reduce`; this method transforms `object` to a new
     * `accumulator` object which is the result of running each of its own enumerable
     * properties through `iteratee`, with each invocation potentially mutating
     * the `accumulator` object. The `iteratee` is bound to `thisArg` and invoked
     * with four arguments: (accumulator, value, key, object). Iteratee functions
     * may exit iteration early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Array|Object} object The object to iterate over.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [accumulator] The custom accumulator value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * _.transform([2, 3, 4], function(result, n) {
     *   result.push(n *= n);
     *   return n % 2 == 0;
     * });
     * // => [4, 9]
     *
     * _.transform({ 'a': 1, 'b': 2 }, function(result, n, key) {
     *   result[key] = n * 3;
     * });
     * // => { 'a': 3, 'b': 6 }
     */
    function transform(object, iteratee, accumulator, thisArg) {
      var isArr = isArray(object) || isTypedArray(object);
      iteratee = getCallback(iteratee, thisArg, 4);

      if (accumulator == null) {
        if (isArr || isObject(object)) {
          var Ctor = object.constructor;
          if (isArr) {
            accumulator = isArray(object) ? new Ctor : [];
          } else {
            accumulator = baseCreate(isFunction(Ctor) && Ctor.prototype);
          }
        } else {
          accumulator = {};
        }
      }
      (isArr ? arrayEach : baseForOwn)(object, function(value, index, object) {
        return iteratee(accumulator, value, index, object);
      });
      return accumulator;
    }

    /**
     * Creates an array of the own enumerable property values of `object`.
     *
     * **Note:** Non-object values are coerced to objects.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property values.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.values(new Foo);
     * // => [1, 2] (iteration order is not guaranteed)
     *
     * _.values('hi');
     * // => ['h', 'i']
     */
    function values(object) {
      return baseValues(object, keys(object));
    }

    /**
     * Creates an array of the own and inherited enumerable property values
     * of `object`.
     *
     * **Note:** Non-object values are coerced to objects.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to query.
     * @returns {Array} Returns the array of property values.
     * @example
     *
     * function Foo() {
     *   this.a = 1;
     *   this.b = 2;
     * }
     *
     * Foo.prototype.c = 3;
     *
     * _.valuesIn(new Foo);
     * // => [1, 2, 3] (iteration order is not guaranteed)
     */
    function valuesIn(object) {
      return baseValues(object, keysIn(object));
    }

    /*------------------------------------------------------------------------*/

    /**
     * Checks if `n` is between `start` and up to but not including, `end`. If
     * `end` is not specified it is set to `start` with `start` then set to `0`.
     *
     * @static
     * @memberOf _
     * @category Number
     * @param {number} n The number to check.
     * @param {number} [start=0] The start of the range.
     * @param {number} end The end of the range.
     * @returns {boolean} Returns `true` if `n` is in the range, else `false`.
     * @example
     *
     * _.inRange(3, 2, 4);
     * // => true
     *
     * _.inRange(4, 8);
     * // => true
     *
     * _.inRange(4, 2);
     * // => false
     *
     * _.inRange(2, 2);
     * // => false
     *
     * _.inRange(1.2, 2);
     * // => true
     *
     * _.inRange(5.2, 4);
     * // => false
     */
    function inRange(value, start, end) {
      start = +start || 0;
      if (typeof end === 'undefined') {
        end = start;
        start = 0;
      } else {
        end = +end || 0;
      }
      return value >= nativeMin(start, end) && value < nativeMax(start, end);
    }

    /**
     * Produces a random number between `min` and `max` (inclusive). If only one
     * argument is provided a number between `0` and the given number is returned.
     * If `floating` is `true`, or either `min` or `max` are floats, a floating-point
     * number is returned instead of an integer.
     *
     * @static
     * @memberOf _
     * @category Number
     * @param {number} [min=0] The minimum possible value.
     * @param {number} [max=1] The maximum possible value.
     * @param {boolean} [floating] Specify returning a floating-point number.
     * @returns {number} Returns the random number.
     * @example
     *
     * _.random(0, 5);
     * // => an integer between 0 and 5
     *
     * _.random(5);
     * // => also an integer between 0 and 5
     *
     * _.random(5, true);
     * // => a floating-point number between 0 and 5
     *
     * _.random(1.2, 5.2);
     * // => a floating-point number between 1.2 and 5.2
     */
    function random(min, max, floating) {
      if (floating && isIterateeCall(min, max, floating)) {
        max = floating = null;
      }
      var noMin = min == null,
          noMax = max == null;

      if (floating == null) {
        if (noMax && typeof min == 'boolean') {
          floating = min;
          min = 1;
        }
        else if (typeof max == 'boolean') {
          floating = max;
          noMax = true;
        }
      }
      if (noMin && noMax) {
        max = 1;
        noMax = false;
      }
      min = +min || 0;
      if (noMax) {
        max = min;
        min = 0;
      } else {
        max = +max || 0;
      }
      if (floating || min % 1 || max % 1) {
        var rand = nativeRandom();
        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + ((rand + '').length - 1)))), max);
      }
      return baseRandom(min, max);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Converts `string` to [camel case](https://en.wikipedia.org/wiki/CamelCase).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the camel cased string.
     * @example
     *
     * _.camelCase('Foo Bar');
     * // => 'fooBar'
     *
     * _.camelCase('--foo-bar');
     * // => 'fooBar'
     *
     * _.camelCase('__foo_bar__');
     * // => 'fooBar'
     */
    var camelCase = createCompounder(function(result, word, index) {
      word = word.toLowerCase();
      return result + (index ? (word.charAt(0).toUpperCase() + word.slice(1)) : word);
    });

    /**
     * Capitalizes the first character of `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to capitalize.
     * @returns {string} Returns the capitalized string.
     * @example
     *
     * _.capitalize('fred');
     * // => 'Fred'
     */
    function capitalize(string) {
      string = baseToString(string);
      return string && (string.charAt(0).toUpperCase() + string.slice(1));
    }

    /**
     * Deburrs `string` by converting [latin-1 supplementary letters](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
     * to basic latin letters and removing [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to deburr.
     * @returns {string} Returns the deburred string.
     * @example
     *
     * _.deburr('déjà vu');
     * // => 'deja vu'
     */
    function deburr(string) {
      string = baseToString(string);
      return string && string.replace(reLatin1, deburrLetter).replace(reComboMark, '');
    }

    /**
     * Checks if `string` ends with the given target string.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to search.
     * @param {string} [target] The string to search for.
     * @param {number} [position=string.length] The position to search from.
     * @returns {boolean} Returns `true` if `string` ends with `target`, else `false`.
     * @example
     *
     * _.endsWith('abc', 'c');
     * // => true
     *
     * _.endsWith('abc', 'b');
     * // => false
     *
     * _.endsWith('abc', 'b', 2);
     * // => true
     */
    function endsWith(string, target, position) {
      string = baseToString(string);
      target = (target + '');

      var length = string.length;
      position = position === undefined
        ? length
        : nativeMin(position < 0 ? 0 : (+position || 0), length);

      position -= target.length;
      return position >= 0 && string.indexOf(target, position) == position;
    }

    /**
     * Converts the characters "&", "<", ">", '"', "'", and "\`", in `string` to
     * their corresponding HTML entities.
     *
     * **Note:** No other characters are escaped. To escape additional characters
     * use a third-party library like [_he_](https://mths.be/he).
     *
     * Though the ">" character is escaped for symmetry, characters like
     * ">" and "/" don't require escaping in HTML and have no special meaning
     * unless they're part of a tag or unquoted attribute value.
     * See [Mathias Bynens's article](https://mathiasbynens.be/notes/ambiguous-ampersands)
     * (under "semi-related fun fact") for more details.
     *
     * Backticks are escaped because in Internet Explorer < 9, they can break out
     * of attribute values or HTML comments. See [#59](https://html5sec.org/#59),
     * [#102](https://html5sec.org/#102), [#108](https://html5sec.org/#108), and
     * [#133](https://html5sec.org/#133) of the [HTML5 Security Cheatsheet](https://html5sec.org/)
     * for more details.
     *
     * When working with HTML you should always [quote attribute values](http://wonko.com/post/html-escaping)
     * to reduce XSS vectors.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to escape.
     * @returns {string} Returns the escaped string.
     * @example
     *
     * _.escape('fred, barney, & pebbles');
     * // => 'fred, barney, &amp; pebbles'
     */
    function escape(string) {
      // Reset `lastIndex` because in IE < 9 `String#replace` does not.
      string = baseToString(string);
      return (string && reHasUnescapedHtml.test(string))
        ? string.replace(reUnescapedHtml, escapeHtmlChar)
        : string;
    }

    /**
     * Escapes the `RegExp` special characters "\", "/", "^", "$", ".", "|", "?",
     * "*", "+", "(", ")", "[", "]", "{" and "}" in `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to escape.
     * @returns {string} Returns the escaped string.
     * @example
     *
     * _.escapeRegExp('[lodash](https://lodash.com/)');
     * // => '\[lodash\]\(https:\/\/lodash\.com\/\)'
     */
    function escapeRegExp(string) {
      string = baseToString(string);
      return (string && reHasRegExpChars.test(string))
        ? string.replace(reRegExpChars, '\\$&')
        : string;
    }

    /**
     * Converts `string` to [kebab case](https://en.wikipedia.org/wiki/Letter_case#Special_case_styles).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the kebab cased string.
     * @example
     *
     * _.kebabCase('Foo Bar');
     * // => 'foo-bar'
     *
     * _.kebabCase('fooBar');
     * // => 'foo-bar'
     *
     * _.kebabCase('__foo_bar__');
     * // => 'foo-bar'
     */
    var kebabCase = createCompounder(function(result, word, index) {
      return result + (index ? '-' : '') + word.toLowerCase();
    });

    /**
     * Pads `string` on the left and right sides if it is shorter than `length`.
     * Padding characters are truncated if they can't be evenly divided by `length`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.pad('abc', 8);
     * // => '  abc   '
     *
     * _.pad('abc', 8, '_-');
     * // => '_-abc_-_'
     *
     * _.pad('abc', 3);
     * // => 'abc'
     */
    function pad(string, length, chars) {
      string = baseToString(string);
      length = +length;

      var strLength = string.length;
      if (strLength >= length || !nativeIsFinite(length)) {
        return string;
      }
      var mid = (length - strLength) / 2,
          leftLength = floor(mid),
          rightLength = ceil(mid);

      chars = createPadding('', rightLength, chars);
      return chars.slice(0, leftLength) + string + chars;
    }

    /**
     * Pads `string` on the left side if it is shorter than `length`. Padding
     * characters are truncated if they exceed `length`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.padLeft('abc', 6);
     * // => '   abc'
     *
     * _.padLeft('abc', 6, '_-');
     * // => '_-_abc'
     *
     * _.padLeft('abc', 3);
     * // => 'abc'
     */
    var padLeft = createPadDir();

    /**
     * Pads `string` on the right side if it is shorter than `length`. Padding
     * characters are truncated if they exceed `length`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.padRight('abc', 6);
     * // => 'abc   '
     *
     * _.padRight('abc', 6, '_-');
     * // => 'abc_-_'
     *
     * _.padRight('abc', 3);
     * // => 'abc'
     */
    var padRight = createPadDir(true);

    /**
     * Converts `string` to an integer of the specified radix. If `radix` is
     * `undefined` or `0`, a `radix` of `10` is used unless `value` is a hexadecimal,
     * in which case a `radix` of `16` is used.
     *
     * **Note:** This method aligns with the [ES5 implementation](https://es5.github.io/#E)
     * of `parseInt`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} string The string to convert.
     * @param {number} [radix] The radix to interpret `value` by.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {number} Returns the converted integer.
     * @example
     *
     * _.parseInt('08');
     * // => 8
     *
     * _.map(['6', '08', '10'], _.parseInt);
     * // => [6, 8, 10]
     */
    function parseInt(string, radix, guard) {
      if (guard && isIterateeCall(string, radix, guard)) {
        radix = 0;
      }
      return nativeParseInt(string, radix);
    }
    // Fallback for environments with pre-ES5 implementations.
    if (nativeParseInt(whitespace + '08') != 8) {
      parseInt = function(string, radix, guard) {
        // Firefox < 21 and Opera < 15 follow ES3 for `parseInt`.
        // Chrome fails to trim leading <BOM> whitespace characters.
        // See https://code.google.com/p/v8/issues/detail?id=3109 for more details.
        if (guard ? isIterateeCall(string, radix, guard) : radix == null) {
          radix = 0;
        } else if (radix) {
          radix = +radix;
        }
        string = trim(string);
        return nativeParseInt(string, radix || (reHasHexPrefix.test(string) ? 16 : 10));
      };
    }

    /**
     * Repeats the given string `n` times.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to repeat.
     * @param {number} [n=0] The number of times to repeat the string.
     * @returns {string} Returns the repeated string.
     * @example
     *
     * _.repeat('*', 3);
     * // => '***'
     *
     * _.repeat('abc', 2);
     * // => 'abcabc'
     *
     * _.repeat('abc', 0);
     * // => ''
     */
    function repeat(string, n) {
      var result = '';
      string = baseToString(string);
      n = +n;
      if (n < 1 || !string || !nativeIsFinite(n)) {
        return result;
      }
      // Leverage the exponentiation by squaring algorithm for a faster repeat.
      // See https://en.wikipedia.org/wiki/Exponentiation_by_squaring for more details.
      do {
        if (n % 2) {
          result += string;
        }
        n = floor(n / 2);
        string += string;
      } while (n);

      return result;
    }

    /**
     * Converts `string` to [snake case](https://en.wikipedia.org/wiki/Snake_case).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the snake cased string.
     * @example
     *
     * _.snakeCase('Foo Bar');
     * // => 'foo_bar'
     *
     * _.snakeCase('fooBar');
     * // => 'foo_bar'
     *
     * _.snakeCase('--foo-bar');
     * // => 'foo_bar'
     */
    var snakeCase = createCompounder(function(result, word, index) {
      return result + (index ? '_' : '') + word.toLowerCase();
    });

    /**
     * Converts `string` to [start case](https://en.wikipedia.org/wiki/Letter_case#Stylistic_or_specialised_usage).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to convert.
     * @returns {string} Returns the start cased string.
     * @example
     *
     * _.startCase('--foo-bar');
     * // => 'Foo Bar'
     *
     * _.startCase('fooBar');
     * // => 'Foo Bar'
     *
     * _.startCase('__foo_bar__');
     * // => 'Foo Bar'
     */
    var startCase = createCompounder(function(result, word, index) {
      return result + (index ? ' ' : '') + (word.charAt(0).toUpperCase() + word.slice(1));
    });

    /**
     * Checks if `string` starts with the given target string.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to search.
     * @param {string} [target] The string to search for.
     * @param {number} [position=0] The position to search from.
     * @returns {boolean} Returns `true` if `string` starts with `target`, else `false`.
     * @example
     *
     * _.startsWith('abc', 'a');
     * // => true
     *
     * _.startsWith('abc', 'b');
     * // => false
     *
     * _.startsWith('abc', 'b', 1);
     * // => true
     */
    function startsWith(string, target, position) {
      string = baseToString(string);
      position = position == null
        ? 0
        : nativeMin(position < 0 ? 0 : (+position || 0), string.length);

      return string.lastIndexOf(target, position) == position;
    }

    /**
     * Creates a compiled template function that can interpolate data properties
     * in "interpolate" delimiters, HTML-escape interpolated data properties in
     * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
     * properties may be accessed as free variables in the template. If a setting
     * object is provided it takes precedence over `_.templateSettings` values.
     *
     * **Note:** In the development build `_.template` utilizes
     * [sourceURLs](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
     * for easier debugging.
     *
     * For more information on precompiling templates see
     * [lodash's custom builds documentation](https://lodash.com/custom-builds).
     *
     * For more information on Chrome extension sandboxes see
     * [Chrome's extensions documentation](https://developer.chrome.com/extensions/sandboxingEval).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The template string.
     * @param {Object} [options] The options object.
     * @param {RegExp} [options.escape] The HTML "escape" delimiter.
     * @param {RegExp} [options.evaluate] The "evaluate" delimiter.
     * @param {Object} [options.imports] An object to import into the template as free variables.
     * @param {RegExp} [options.interpolate] The "interpolate" delimiter.
     * @param {string} [options.sourceURL] The sourceURL of the template's compiled source.
     * @param {string} [options.variable] The data object variable name.
     * @param- {Object} [otherOptions] Enables the legacy `options` param signature.
     * @returns {Function} Returns the compiled template function.
     * @example
     *
     * // using the "interpolate" delimiter to create a compiled template
     * var compiled = _.template('hello <%= user %>!');
     * compiled({ 'user': 'fred' });
     * // => 'hello fred!'
     *
     * // using the HTML "escape" delimiter to escape data property values
     * var compiled = _.template('<b><%- value %></b>');
     * compiled({ 'value': '<script>' });
     * // => '<b>&lt;script&gt;</b>'
     *
     * // using the "evaluate" delimiter to execute JavaScript and generate HTML
     * var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
     * compiled({ 'users': ['fred', 'barney'] });
     * // => '<li>fred</li><li>barney</li>'
     *
     * // using the internal `print` function in "evaluate" delimiters
     * var compiled = _.template('<% print("hello " + user); %>!');
     * compiled({ 'user': 'barney' });
     * // => 'hello barney!'
     *
     * // using the ES delimiter as an alternative to the default "interpolate" delimiter
     * var compiled = _.template('hello ${ user }!');
     * compiled({ 'user': 'pebbles' });
     * // => 'hello pebbles!'
     *
     * // using custom template delimiters
     * _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
     * var compiled = _.template('hello {{ user }}!');
     * compiled({ 'user': 'mustache' });
     * // => 'hello mustache!'
     *
     * // using backslashes to treat delimiters as plain text
     * var compiled = _.template('<%= "\\<%- value %\\>" %>');
     * compiled({ 'value': 'ignored' });
     * // => '<%- value %>'
     *
     * // using the `imports` option to import `jQuery` as `jq`
     * var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
     * var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
     * compiled({ 'users': ['fred', 'barney'] });
     * // => '<li>fred</li><li>barney</li>'
     *
     * // using the `sourceURL` option to specify a custom sourceURL for the template
     * var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
     * compiled(data);
     * // => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
     *
     * // using the `variable` option to ensure a with-statement isn't used in the compiled template
     * var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
     * compiled.source;
     * // => function(data) {
     * //   var __t, __p = '';
     * //   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
     * //   return __p;
     * // }
     *
     * // using the `source` property to inline compiled templates for meaningful
     * // line numbers in error messages and a stack trace
     * fs.writeFileSync(path.join(cwd, 'jst.js'), '\
     *   var JST = {\
     *     "main": ' + _.template(mainText).source + '\
     *   };\
     * ');
     */
    function template(string, options, otherOptions) {
      // Based on John Resig's `tmpl` implementation (http://ejohn.org/blog/javascript-micro-templating/)
      // and Laura Doktorova's doT.js (https://github.com/olado/doT).
      var settings = lodash.templateSettings;

      if (otherOptions && isIterateeCall(string, options, otherOptions)) {
        options = otherOptions = null;
      }
      string = baseToString(string);
      options = assignWith(baseAssign({}, otherOptions || options), settings, assignOwnDefaults);

      var imports = assignWith(baseAssign({}, options.imports), settings.imports, assignOwnDefaults),
          importsKeys = keys(imports),
          importsValues = baseValues(imports, importsKeys);

      var isEscaping,
          isEvaluating,
          index = 0,
          interpolate = options.interpolate || reNoMatch,
          source = "__p += '";

      // Compile the regexp to match each delimiter.
      var reDelimiters = RegExp(
        (options.escape || reNoMatch).source + '|' +
        interpolate.source + '|' +
        (interpolate === reInterpolate ? reEsTemplate : reNoMatch).source + '|' +
        (options.evaluate || reNoMatch).source + '|$'
      , 'g');

      // Use a sourceURL for easier debugging.
      var sourceURL = '//# sourceURL=' +
        ('sourceURL' in options
          ? options.sourceURL
          : ('lodash.templateSources[' + (++templateCounter) + ']')
        ) + '\n';

      string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
        interpolateValue || (interpolateValue = esTemplateValue);

        // Escape characters that can't be included in string literals.
        source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);

        // Replace delimiters with snippets.
        if (escapeValue) {
          isEscaping = true;
          source += "' +\n__e(" + escapeValue + ") +\n'";
        }
        if (evaluateValue) {
          isEvaluating = true;
          source += "';\n" + evaluateValue + ";\n__p += '";
        }
        if (interpolateValue) {
          source += "' +\n((__t = (" + interpolateValue + ")) == null ? '' : __t) +\n'";
        }
        index = offset + match.length;

        // The JS engine embedded in Adobe products requires returning the `match`
        // string in order to produce the correct `offset` value.
        return match;
      });

      source += "';\n";

      // If `variable` is not specified wrap a with-statement around the generated
      // code to add the data object to the top of the scope chain.
      var variable = options.variable;
      if (!variable) {
        source = 'with (obj) {\n' + source + '\n}\n';
      }
      // Cleanup code by stripping empty strings.
      source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
        .replace(reEmptyStringMiddle, '$1')
        .replace(reEmptyStringTrailing, '$1;');

      // Frame code as the function body.
      source = 'function(' + (variable || 'obj') + ') {\n' +
        (variable
          ? ''
          : 'obj || (obj = {});\n'
        ) +
        "var __t, __p = ''" +
        (isEscaping
           ? ', __e = _.escape'
           : ''
        ) +
        (isEvaluating
          ? ', __j = Array.prototype.join;\n' +
            "function print() { __p += __j.call(arguments, '') }\n"
          : ';\n'
        ) +
        source +
        'return __p\n}';

      var result = attempt(function() {
        return Function(importsKeys, sourceURL + 'return ' + source).apply(undefined, importsValues);
      });

      // Provide the compiled function's source by its `toString` method or
      // the `source` property as a convenience for inlining compiled templates.
      result.source = source;
      if (isError(result)) {
        throw result;
      }
      return result;
    }

    /**
     * Removes leading and trailing whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trim('  abc  ');
     * // => 'abc'
     *
     * _.trim('-_-abc-_-', '_-');
     * // => 'abc'
     *
     * _.map(['  foo  ', '  bar  '], _.trim);
     * // => ['foo', 'bar']
     */
    function trim(string, chars, guard) {
      var value = string;
      string = baseToString(string);
      if (!string) {
        return string;
      }
      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
        return string.slice(trimmedLeftIndex(string), trimmedRightIndex(string) + 1);
      }
      chars = (chars + '');
      return string.slice(charsLeftIndex(string, chars), charsRightIndex(string, chars) + 1);
    }

    /**
     * Removes leading whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trimLeft('  abc  ');
     * // => 'abc  '
     *
     * _.trimLeft('-_-abc-_-', '_-');
     * // => 'abc-_-'
     */
    function trimLeft(string, chars, guard) {
      var value = string;
      string = baseToString(string);
      if (!string) {
        return string;
      }
      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
        return string.slice(trimmedLeftIndex(string));
      }
      return string.slice(charsLeftIndex(string, (chars + '')));
    }

    /**
     * Removes trailing whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trimRight('  abc  ');
     * // => '  abc'
     *
     * _.trimRight('-_-abc-_-', '_-');
     * // => '-_-abc'
     */
    function trimRight(string, chars, guard) {
      var value = string;
      string = baseToString(string);
      if (!string) {
        return string;
      }
      if (guard ? isIterateeCall(value, chars, guard) : chars == null) {
        return string.slice(0, trimmedRightIndex(string) + 1);
      }
      return string.slice(0, charsRightIndex(string, (chars + '')) + 1);
    }

    /**
     * Truncates `string` if it is longer than the given maximum string length.
     * The last characters of the truncated string are replaced with the omission
     * string which defaults to "...".
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to truncate.
     * @param {Object|number} [options] The options object or maximum string length.
     * @param {number} [options.length=30] The maximum string length.
     * @param {string} [options.omission='...'] The string to indicate text is omitted.
     * @param {RegExp|string} [options.separator] The separator pattern to truncate to.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the truncated string.
     * @example
     *
     * _.trunc('hi-diddly-ho there, neighborino');
     * // => 'hi-diddly-ho there, neighbo...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', 24);
     * // => 'hi-diddly-ho there, n...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', {
     *   'length': 24,
     *   'separator': ' '
     * });
     * // => 'hi-diddly-ho there,...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', {
     *   'length': 24,
     *   'separator': /,? +/
     * });
     * // => 'hi-diddly-ho there...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', {
     *   'omission': ' [...]'
     * });
     * // => 'hi-diddly-ho there, neig [...]'
     */
    function trunc(string, options, guard) {
      if (guard && isIterateeCall(string, options, guard)) {
        options = null;
      }
      var length = DEFAULT_TRUNC_LENGTH,
          omission = DEFAULT_TRUNC_OMISSION;

      if (options != null) {
        if (isObject(options)) {
          var separator = 'separator' in options ? options.separator : separator;
          length = 'length' in options ? (+options.length || 0) : length;
          omission = 'omission' in options ? baseToString(options.omission) : omission;
        } else {
          length = +options || 0;
        }
      }
      string = baseToString(string);
      if (length >= string.length) {
        return string;
      }
      var end = length - omission.length;
      if (end < 1) {
        return omission;
      }
      var result = string.slice(0, end);
      if (separator == null) {
        return result + omission;
      }
      if (isRegExp(separator)) {
        if (string.slice(end).search(separator)) {
          var match,
              newEnd,
              substring = string.slice(0, end);

          if (!separator.global) {
            separator = RegExp(separator.source, (reFlags.exec(separator) || '') + 'g');
          }
          separator.lastIndex = 0;
          while ((match = separator.exec(substring))) {
            newEnd = match.index;
          }
          result = result.slice(0, newEnd == null ? end : newEnd);
        }
      } else if (string.indexOf(separator, end) != end) {
        var index = result.lastIndexOf(separator);
        if (index > -1) {
          result = result.slice(0, index);
        }
      }
      return result + omission;
    }

    /**
     * The inverse of `_.escape`; this method converts the HTML entities
     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, `&#39;`, and `&#96;` in `string` to their
     * corresponding characters.
     *
     * **Note:** No other HTML entities are unescaped. To unescape additional HTML
     * entities use a third-party library like [_he_](https://mths.be/he).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to unescape.
     * @returns {string} Returns the unescaped string.
     * @example
     *
     * _.unescape('fred, barney, &amp; pebbles');
     * // => 'fred, barney, & pebbles'
     */
    function unescape(string) {
      string = baseToString(string);
      return (string && reHasEscapedHtml.test(string))
        ? string.replace(reEscapedHtml, unescapeHtmlChar)
        : string;
    }

    /**
     * Splits `string` into an array of its words.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to inspect.
     * @param {RegExp|string} [pattern] The pattern to match words.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the words of `string`.
     * @example
     *
     * _.words('fred, barney, & pebbles');
     * // => ['fred', 'barney', 'pebbles']
     *
     * _.words('fred, barney, & pebbles', /[^, ]+/g);
     * // => ['fred', 'barney', '&', 'pebbles']
     */
    function words(string, pattern, guard) {
      if (guard && isIterateeCall(string, pattern, guard)) {
        pattern = null;
      }
      string = baseToString(string);
      return string.match(pattern || reWords) || [];
    }

    /*------------------------------------------------------------------------*/

    /**
     * Attempts to invoke `func`, returning either the result or the caught error
     * object. Any additional arguments are provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Function} func The function to attempt.
     * @returns {*} Returns the `func` result or error object.
     * @example
     *
     * // avoid throwing errors for invalid selectors
     * var elements = _.attempt(function(selector) {
     *   return document.querySelectorAll(selector);
     * }, '>_>');
     *
     * if (_.isError(elements)) {
     *   elements = [];
     * }
     */
    var attempt = restParam(function(func, args) {
      try {
        return func.apply(undefined, args);
      } catch(e) {
        return isError(e) ? e : new Error(e);
      }
    });

    /**
     * Creates a function that invokes `func` with the `this` binding of `thisArg`
     * and arguments of the created function. If `func` is a property name the
     * created callback returns the property value for a given element. If `func`
     * is an object the created callback returns `true` for elements that contain
     * the equivalent object properties, otherwise it returns `false`.
     *
     * @static
     * @memberOf _
     * @alias iteratee
     * @category Utility
     * @param {*} [func=_.identity] The value to convert to a callback.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the callback.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // wrap to create custom callback shorthands
     * _.callback = _.wrap(_.callback, function(callback, func, thisArg) {
     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(func);
     *   if (!match) {
     *     return callback(func, thisArg);
     *   }
     *   return function(object) {
     *     return match[2] == 'gt'
     *       ? object[match[1]] > match[3]
     *       : object[match[1]] < match[3];
     *   };
     * });
     *
     * _.filter(users, 'age__gt36');
     * // => [{ 'user': 'fred', 'age': 40 }]
     */
    function callback(func, thisArg, guard) {
      if (guard && isIterateeCall(func, thisArg, guard)) {
        thisArg = null;
      }
      return baseCallback(func, thisArg);
    }

    /**
     * Creates a function that returns `value`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} value The value to return from the new function.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var object = { 'user': 'fred' };
     * var getter = _.constant(object);
     *
     * getter() === object;
     * // => true
     */
    function constant(value) {
      return function() {
        return value;
      };
    }

    /**
     * This method returns the first argument provided to it.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} value Any value.
     * @returns {*} Returns `value`.
     * @example
     *
     * var object = { 'user': 'fred' };
     *
     * _.identity(object) === object;
     * // => true
     */
    function identity(value) {
      return value;
    }

    /**
     * Creates a function which performs a deep comparison between a given object
     * and `source`, returning `true` if the given object has equivalent property
     * values, else `false`.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties. For comparing a single
     * own or inherited property value see `_.matchesProperty`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} source The object of property values to match.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'active': true },
     *   { 'user': 'fred',   'age': 40, 'active': false }
     * ];
     *
     * _.filter(users, _.matches({ 'age': 40, 'active': false }));
     * // => [{ 'user': 'fred', 'age': 40, 'active': false }]
     */
    function matches(source) {
      return baseMatches(baseClone(source, true));
    }

    /**
     * Creates a function which compares the property value of `path` on a given
     * object to `value`.
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Objects are compared by
     * their own, not inherited, enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Array|string} path The path of the property to get.
     * @param {*} value The value to compare.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'barney' },
     *   { 'user': 'fred' }
     * ];
     *
     * _.find(users, _.matchesProperty('user', 'fred'));
     * // => { 'user': 'fred' }
     */
    function matchesProperty(path, value) {
      return baseMatchesProperty(path, baseClone(value, true));
    }

    /**
     * Creates a function which invokes the method at `path` on a given object.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Array|string} path The path of the method to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var objects = [
     *   { 'a': { 'b': { 'c': _.constant(2) } } },
     *   { 'a': { 'b': { 'c': _.constant(1) } } }
     * ];
     *
     * _.map(objects, _.method('a.b.c'));
     * // => [2, 1]
     *
     * _.invoke(_.sortBy(objects, _.method(['a', 'b', 'c'])), 'a.b.c');
     * // => [1, 2]
     */
    var method = restParam(function(path, args) {
      return function(object) {
        return invokePath(object, path, args);
      }
    });

    /**
     * The opposite of `_.method`; this method creates a function which invokes
     * the method at a given path on `object`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} object The object to query.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var array = _.times(3, _.constant),
     *     object = { 'a': array, 'b': array, 'c': array };
     *
     * _.map(['a[2]', 'c[0]'], _.methodOf(object));
     * // => [2, 0]
     *
     * _.map([['a', '2'], ['c', '0']], _.methodOf(object));
     * // => [2, 0]
     */
    var methodOf = restParam(function(object, args) {
      return function(path) {
        return invokePath(object, path, args);
      };
    });

    /**
     * Adds all own enumerable function properties of a source object to the
     * destination object. If `object` is a function then methods are added to
     * its prototype as well.
     *
     * **Note:** Use `_.runInContext` to create a pristine `lodash` function to
     * avoid conflicts caused by modifying the original.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Function|Object} [object=lodash] The destination object.
     * @param {Object} source The object of functions to add.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.chain=true] Specify whether the functions added
     *  are chainable.
     * @returns {Function|Object} Returns `object`.
     * @example
     *
     * function vowels(string) {
     *   return _.filter(string, function(v) {
     *     return /[aeiou]/i.test(v);
     *   });
     * }
     *
     * // use `_.runInContext` to avoid conflicts (esp. in Node.js)
     * var _ = require('lodash').runInContext();
     *
     * _.mixin({ 'vowels': vowels });
     * _.vowels('fred');
     * // => ['e']
     *
     * _('fred').vowels().value();
     * // => ['e']
     *
     * _.mixin({ 'vowels': vowels }, { 'chain': false });
     * _('fred').vowels();
     * // => ['e']
     */
    function mixin(object, source, options) {
      if (options == null) {
        var isObj = isObject(source),
            props = isObj && keys(source),
            methodNames = props && props.length && baseFunctions(source, props);

        if (!(methodNames ? methodNames.length : isObj)) {
          methodNames = false;
          options = source;
          source = object;
          object = this;
        }
      }
      if (!methodNames) {
        methodNames = baseFunctions(source, keys(source));
      }
      var chain = true,
          index = -1,
          isFunc = isFunction(object),
          length = methodNames.length;

      if (options === false) {
        chain = false;
      } else if (isObject(options) && 'chain' in options) {
        chain = options.chain;
      }
      while (++index < length) {
        var methodName = methodNames[index],
            func = source[methodName];

        object[methodName] = func;
        if (isFunc) {
          object.prototype[methodName] = (function(func) {
            return function() {
              var chainAll = this.__chain__;
              if (chain || chainAll) {
                var result = object(this.__wrapped__),
                    actions = result.__actions__ = arrayCopy(this.__actions__);

                actions.push({ 'func': func, 'args': arguments, 'thisArg': object });
                result.__chain__ = chainAll;
                return result;
              }
              var args = [this.value()];
              push.apply(args, arguments);
              return func.apply(object, args);
            };
          }(func));
        }
      }
      return object;
    }

    /**
     * Reverts the `_` variable to its previous value and returns a reference to
     * the `lodash` function.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @returns {Function} Returns the `lodash` function.
     * @example
     *
     * var lodash = _.noConflict();
     */
    function noConflict() {
      context._ = oldDash;
      return this;
    }

    /**
     * A no-operation function which returns `undefined` regardless of the
     * arguments it receives.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @example
     *
     * var object = { 'user': 'fred' };
     *
     * _.noop(object) === undefined;
     * // => true
     */
    function noop() {
      // No operation performed.
    }

    /**
     * Creates a function which returns the property value at `path` on a
     * given object.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Array|string} path The path of the property to get.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var objects = [
     *   { 'a': { 'b': { 'c': 2 } } },
     *   { 'a': { 'b': { 'c': 1 } } }
     * ];
     *
     * _.map(objects, _.property('a.b.c'));
     * // => [2, 1]
     *
     * _.pluck(_.sortBy(objects, _.property(['a', 'b', 'c'])), 'a.b.c');
     * // => [1, 2]
     */
    function property(path) {
      return isKey(path) ? baseProperty(path) : basePropertyDeep(path);
    }

    /**
     * The opposite of `_.property`; this method creates a function which returns
     * the property value at a given path on `object`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} object The object to query.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var array = [0, 1, 2],
     *     object = { 'a': array, 'b': array, 'c': array };
     *
     * _.map(['a[2]', 'c[0]'], _.propertyOf(object));
     * // => [2, 0]
     *
     * _.map([['a', '2'], ['c', '0']], _.propertyOf(object));
     * // => [2, 0]
     */
    function propertyOf(object) {
      return function(path) {
        return baseGet(object, toPath(path), path + '');
      };
    }

    /**
     * Creates an array of numbers (positive and/or negative) progressing from
     * `start` up to, but not including, `end`. If `end` is not specified it is
     * set to `start` with `start` then set to `0`. If `end` is less than `start`
     * a zero-length range is created unless a negative `step` is specified.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} [start=0] The start of the range.
     * @param {number} end The end of the range.
     * @param {number} [step=1] The value to increment or decrement by.
     * @returns {Array} Returns the new array of numbers.
     * @example
     *
     * _.range(4);
     * // => [0, 1, 2, 3]
     *
     * _.range(1, 5);
     * // => [1, 2, 3, 4]
     *
     * _.range(0, 20, 5);
     * // => [0, 5, 10, 15]
     *
     * _.range(0, -4, -1);
     * // => [0, -1, -2, -3]
     *
     * _.range(1, 4, 0);
     * // => [1, 1, 1]
     *
     * _.range(0);
     * // => []
     */
    function range(start, end, step) {
      if (step && isIterateeCall(start, end, step)) {
        end = step = null;
      }
      start = +start || 0;
      step = step == null ? 1 : (+step || 0);

      if (end == null) {
        end = start;
        start = 0;
      } else {
        end = +end || 0;
      }
      // Use `Array(length)` so engines like Chakra and V8 avoid slower modes.
      // See https://youtu.be/XAqIpGU8ZZk#t=17m25s for more details.
      var index = -1,
          length = nativeMax(ceil((end - start) / (step || 1)), 0),
          result = Array(length);

      while (++index < length) {
        result[index] = start;
        start += step;
      }
      return result;
    }

    /**
     * Invokes the iteratee function `n` times, returning an array of the results
     * of each invocation. The `iteratee` is bound to `thisArg` and invoked with
     * one argument; (index).
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} n The number of times to invoke `iteratee`.
     * @param {Function} [iteratee=_.identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the array of results.
     * @example
     *
     * var diceRolls = _.times(3, _.partial(_.random, 1, 6, false));
     * // => [3, 6, 4]
     *
     * _.times(3, function(n) {
     *   mage.castSpell(n);
     * });
     * // => invokes `mage.castSpell(n)` three times with `n` of `0`, `1`, and `2`
     *
     * _.times(3, function(n) {
     *   this.cast(n);
     * }, mage);
     * // => also invokes `mage.castSpell(n)` three times
     */
    function times(n, iteratee, thisArg) {
      n = floor(n);

      // Exit early to avoid a JSC JIT bug in Safari 8
      // where `Array(0)` is treated as `Array(1)`.
      if (n < 1 || !nativeIsFinite(n)) {
        return [];
      }
      var index = -1,
          result = Array(nativeMin(n, MAX_ARRAY_LENGTH));

      iteratee = bindCallback(iteratee, thisArg, 1);
      while (++index < n) {
        if (index < MAX_ARRAY_LENGTH) {
          result[index] = iteratee(index);
        } else {
          iteratee(index);
        }
      }
      return result;
    }

    /**
     * Generates a unique ID. If `prefix` is provided the ID is appended to it.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {string} [prefix] The value to prefix the ID with.
     * @returns {string} Returns the unique ID.
     * @example
     *
     * _.uniqueId('contact_');
     * // => 'contact_104'
     *
     * _.uniqueId();
     * // => '105'
     */
    function uniqueId(prefix) {
      var id = ++idCounter;
      return baseToString(prefix) + id;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Adds two numbers.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {number} augend The first number to add.
     * @param {number} addend The second number to add.
     * @returns {number} Returns the sum.
     * @example
     *
     * _.add(6, 4);
     * // => 10
     */
    function add(augend, addend) {
      return (+augend || 0) + (+addend || 0);
    }

    /**
     * Gets the maximum value of `collection`. If `collection` is empty or falsey
     * `-Infinity` is returned. If an iteratee function is provided it is invoked
     * for each value in `collection` to generate the criterion by which the value
     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the maximum value.
     * @example
     *
     * _.max([4, 2, 8, 6]);
     * // => 8
     *
     * _.max([]);
     * // => -Infinity
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.max(users, function(chr) {
     *   return chr.age;
     * });
     * // => { 'user': 'fred', 'age': 40 }
     *
     * // using the `_.property` callback shorthand
     * _.max(users, 'age');
     * // => { 'user': 'fred', 'age': 40 }
     */
    var max = createExtremum(arrayMax);

    /**
     * Gets the minimum value of `collection`. If `collection` is empty or falsey
     * `Infinity` is returned. If an iteratee function is provided it is invoked
     * for each value in `collection` to generate the criterion by which the value
     * is ranked. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments: (value, index, collection).
     *
     * If a property name is provided for `iteratee` the created `_.property`
     * style callback returns the property value of the given element.
     *
     * If a value is also provided for `thisArg` the created `_.matchesProperty`
     * style callback returns `true` for elements that have a matching property
     * value, else `false`.
     *
     * If an object is provided for `iteratee` the created `_.matches` style
     * callback returns `true` for elements that have the properties of the given
     * object, else `false`.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the minimum value.
     * @example
     *
     * _.min([4, 2, 8, 6]);
     * // => 2
     *
     * _.min([]);
     * // => Infinity
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.min(users, function(chr) {
     *   return chr.age;
     * });
     * // => { 'user': 'barney', 'age': 36 }
     *
     * // using the `_.property` callback shorthand
     * _.min(users, 'age');
     * // => { 'user': 'barney', 'age': 36 }
     */
    var min = createExtremum(arrayMin, true);

    /**
     * Gets the sum of the values in `collection`.
     *
     * @static
     * @memberOf _
     * @category Math
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the sum.
     * @example
     *
     * _.sum([4, 6]);
     * // => 10
     *
     * _.sum({ 'a': 4, 'b': 6 });
     * // => 10
     *
     * var objects = [
     *   { 'n': 4 },
     *   { 'n': 6 }
     * ];
     *
     * _.sum(objects, function(object) {
     *   return object.n;
     * });
     * // => 10
     *
     * // using the `_.property` callback shorthand
     * _.sum(objects, 'n');
     * // => 10
     */
    function sum(collection, iteratee, thisArg) {
      if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
        iteratee = null;
      }
      var func = getCallback(),
          noIteratee = iteratee == null;

      if (!(func === baseCallback && noIteratee)) {
        noIteratee = false;
        iteratee = func(iteratee, thisArg, 3);
      }
      return noIteratee
        ? arraySum(isArray(collection) ? collection : toIterable(collection))
        : baseSum(collection, iteratee);
    }

    /*------------------------------------------------------------------------*/

    // Ensure wrappers are instances of `baseLodash`.
    lodash.prototype = baseLodash.prototype;

    LodashWrapper.prototype = baseCreate(baseLodash.prototype);
    LodashWrapper.prototype.constructor = LodashWrapper;

    LazyWrapper.prototype = baseCreate(baseLodash.prototype);
    LazyWrapper.prototype.constructor = LazyWrapper;

    // Add functions to the `Map` cache.
    MapCache.prototype['delete'] = mapDelete;
    MapCache.prototype.get = mapGet;
    MapCache.prototype.has = mapHas;
    MapCache.prototype.set = mapSet;

    // Add functions to the `Set` cache.
    SetCache.prototype.push = cachePush;

    // Assign cache to `_.memoize`.
    memoize.Cache = MapCache;

    // Add functions that return wrapped values when chaining.
    lodash.after = after;
    lodash.ary = ary;
    lodash.assign = assign;
    lodash.at = at;
    lodash.before = before;
    lodash.bind = bind;
    lodash.bindAll = bindAll;
    lodash.bindKey = bindKey;
    lodash.callback = callback;
    lodash.chain = chain;
    lodash.chunk = chunk;
    lodash.compact = compact;
    lodash.constant = constant;
    lodash.countBy = countBy;
    lodash.create = create;
    lodash.curry = curry;
    lodash.curryRight = curryRight;
    lodash.debounce = debounce;
    lodash.defaults = defaults;
    lodash.defer = defer;
    lodash.delay = delay;
    lodash.difference = difference;
    lodash.drop = drop;
    lodash.dropRight = dropRight;
    lodash.dropRightWhile = dropRightWhile;
    lodash.dropWhile = dropWhile;
    lodash.fill = fill;
    lodash.filter = filter;
    lodash.flatten = flatten;
    lodash.flattenDeep = flattenDeep;
    lodash.flow = flow;
    lodash.flowRight = flowRight;
    lodash.forEach = forEach;
    lodash.forEachRight = forEachRight;
    lodash.forIn = forIn;
    lodash.forInRight = forInRight;
    lodash.forOwn = forOwn;
    lodash.forOwnRight = forOwnRight;
    lodash.functions = functions;
    lodash.groupBy = groupBy;
    lodash.indexBy = indexBy;
    lodash.initial = initial;
    lodash.intersection = intersection;
    lodash.invert = invert;
    lodash.invoke = invoke;
    lodash.keys = keys;
    lodash.keysIn = keysIn;
    lodash.map = map;
    lodash.mapValues = mapValues;
    lodash.matches = matches;
    lodash.matchesProperty = matchesProperty;
    lodash.memoize = memoize;
    lodash.merge = merge;
    lodash.method = method;
    lodash.methodOf = methodOf;
    lodash.mixin = mixin;
    lodash.negate = negate;
    lodash.omit = omit;
    lodash.once = once;
    lodash.pairs = pairs;
    lodash.partial = partial;
    lodash.partialRight = partialRight;
    lodash.partition = partition;
    lodash.pick = pick;
    lodash.pluck = pluck;
    lodash.property = property;
    lodash.propertyOf = propertyOf;
    lodash.pull = pull;
    lodash.pullAt = pullAt;
    lodash.range = range;
    lodash.rearg = rearg;
    lodash.reject = reject;
    lodash.remove = remove;
    lodash.rest = rest;
    lodash.restParam = restParam;
    lodash.set = set;
    lodash.shuffle = shuffle;
    lodash.slice = slice;
    lodash.sortBy = sortBy;
    lodash.sortByAll = sortByAll;
    lodash.sortByOrder = sortByOrder;
    lodash.spread = spread;
    lodash.take = take;
    lodash.takeRight = takeRight;
    lodash.takeRightWhile = takeRightWhile;
    lodash.takeWhile = takeWhile;
    lodash.tap = tap;
    lodash.throttle = throttle;
    lodash.thru = thru;
    lodash.times = times;
    lodash.toArray = toArray;
    lodash.toPlainObject = toPlainObject;
    lodash.transform = transform;
    lodash.union = union;
    lodash.uniq = uniq;
    lodash.unzip = unzip;
    lodash.values = values;
    lodash.valuesIn = valuesIn;
    lodash.where = where;
    lodash.without = without;
    lodash.wrap = wrap;
    lodash.xor = xor;
    lodash.zip = zip;
    lodash.zipObject = zipObject;

    // Add aliases.
    lodash.backflow = flowRight;
    lodash.collect = map;
    lodash.compose = flowRight;
    lodash.each = forEach;
    lodash.eachRight = forEachRight;
    lodash.extend = assign;
    lodash.iteratee = callback;
    lodash.methods = functions;
    lodash.object = zipObject;
    lodash.select = filter;
    lodash.tail = rest;
    lodash.unique = uniq;

    // Add functions to `lodash.prototype`.
    mixin(lodash, lodash);

    /*------------------------------------------------------------------------*/

    // Add functions that return unwrapped values when chaining.
    lodash.add = add;
    lodash.attempt = attempt;
    lodash.camelCase = camelCase;
    lodash.capitalize = capitalize;
    lodash.clone = clone;
    lodash.cloneDeep = cloneDeep;
    lodash.deburr = deburr;
    lodash.endsWith = endsWith;
    lodash.escape = escape;
    lodash.escapeRegExp = escapeRegExp;
    lodash.every = every;
    lodash.find = find;
    lodash.findIndex = findIndex;
    lodash.findKey = findKey;
    lodash.findLast = findLast;
    lodash.findLastIndex = findLastIndex;
    lodash.findLastKey = findLastKey;
    lodash.findWhere = findWhere;
    lodash.first = first;
    lodash.get = get;
    lodash.has = has;
    lodash.identity = identity;
    lodash.includes = includes;
    lodash.indexOf = indexOf;
    lodash.inRange = inRange;
    lodash.isArguments = isArguments;
    lodash.isArray = isArray;
    lodash.isBoolean = isBoolean;
    lodash.isDate = isDate;
    lodash.isElement = isElement;
    lodash.isEmpty = isEmpty;
    lodash.isEqual = isEqual;
    lodash.isError = isError;
    lodash.isFinite = isFinite;
    lodash.isFunction = isFunction;
    lodash.isMatch = isMatch;
    lodash.isNaN = isNaN;
    lodash.isNative = isNative;
    lodash.isNull = isNull;
    lodash.isNumber = isNumber;
    lodash.isObject = isObject;
    lodash.isPlainObject = isPlainObject;
    lodash.isRegExp = isRegExp;
    lodash.isString = isString;
    lodash.isTypedArray = isTypedArray;
    lodash.isUndefined = isUndefined;
    lodash.kebabCase = kebabCase;
    lodash.last = last;
    lodash.lastIndexOf = lastIndexOf;
    lodash.max = max;
    lodash.min = min;
    lodash.noConflict = noConflict;
    lodash.noop = noop;
    lodash.now = now;
    lodash.pad = pad;
    lodash.padLeft = padLeft;
    lodash.padRight = padRight;
    lodash.parseInt = parseInt;
    lodash.random = random;
    lodash.reduce = reduce;
    lodash.reduceRight = reduceRight;
    lodash.repeat = repeat;
    lodash.result = result;
    lodash.runInContext = runInContext;
    lodash.size = size;
    lodash.snakeCase = snakeCase;
    lodash.some = some;
    lodash.sortedIndex = sortedIndex;
    lodash.sortedLastIndex = sortedLastIndex;
    lodash.startCase = startCase;
    lodash.startsWith = startsWith;
    lodash.sum = sum;
    lodash.template = template;
    lodash.trim = trim;
    lodash.trimLeft = trimLeft;
    lodash.trimRight = trimRight;
    lodash.trunc = trunc;
    lodash.unescape = unescape;
    lodash.uniqueId = uniqueId;
    lodash.words = words;

    // Add aliases.
    lodash.all = every;
    lodash.any = some;
    lodash.contains = includes;
    lodash.detect = find;
    lodash.foldl = reduce;
    lodash.foldr = reduceRight;
    lodash.head = first;
    lodash.include = includes;
    lodash.inject = reduce;

    mixin(lodash, (function() {
      var source = {};
      baseForOwn(lodash, function(func, methodName) {
        if (!lodash.prototype[methodName]) {
          source[methodName] = func;
        }
      });
      return source;
    }()), false);

    /*------------------------------------------------------------------------*/

    // Add functions capable of returning wrapped and unwrapped values when chaining.
    lodash.sample = sample;

    lodash.prototype.sample = function(n) {
      if (!this.__chain__ && n == null) {
        return sample(this.value());
      }
      return this.thru(function(value) {
        return sample(value, n);
      });
    };

    /*------------------------------------------------------------------------*/

    /**
     * The semantic version number.
     *
     * @static
     * @memberOf _
     * @type string
     */
    lodash.VERSION = VERSION;

    // Assign default placeholders.
    arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'], function(methodName) {
      lodash[methodName].placeholder = lodash;
    });

    // Add `LazyWrapper` methods that accept an `iteratee` value.
    arrayEach(['dropWhile', 'filter', 'map', 'takeWhile'], function(methodName, type) {
      var isFilter = type != LAZY_MAP_FLAG,
          isDropWhile = type == LAZY_DROP_WHILE_FLAG;

      LazyWrapper.prototype[methodName] = function(iteratee, thisArg) {
        var filtered = this.__filtered__,
            result = (filtered && isDropWhile) ? new LazyWrapper(this) : this.clone(),
            iteratees = result.__iteratees__ || (result.__iteratees__ = []);

        iteratees.push({
          'done': false,
          'count': 0,
          'index': 0,
          'iteratee': getCallback(iteratee, thisArg, 1),
          'limit': -1,
          'type': type
        });

        result.__filtered__ = filtered || isFilter;
        return result;
      };
    });

    // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
    arrayEach(['drop', 'take'], function(methodName, index) {
      var whileName = methodName + 'While';

      LazyWrapper.prototype[methodName] = function(n) {
        var filtered = this.__filtered__,
            result = (filtered && !index) ? this.dropWhile() : this.clone();

        n = n == null ? 1 : nativeMax(floor(n) || 0, 0);
        if (filtered) {
          if (index) {
            result.__takeCount__ = nativeMin(result.__takeCount__, n);
          } else {
            last(result.__iteratees__).limit = n;
          }
        } else {
          var views = result.__views__ || (result.__views__ = []);
          views.push({ 'size': n, 'type': methodName + (result.__dir__ < 0 ? 'Right' : '') });
        }
        return result;
      };

      LazyWrapper.prototype[methodName + 'Right'] = function(n) {
        return this.reverse()[methodName](n).reverse();
      };

      LazyWrapper.prototype[methodName + 'RightWhile'] = function(predicate, thisArg) {
        return this.reverse()[whileName](predicate, thisArg).reverse();
      };
    });

    // Add `LazyWrapper` methods for `_.first` and `_.last`.
    arrayEach(['first', 'last'], function(methodName, index) {
      var takeName = 'take' + (index ? 'Right' : '');

      LazyWrapper.prototype[methodName] = function() {
        return this[takeName](1).value()[0];
      };
    });

    // Add `LazyWrapper` methods for `_.initial` and `_.rest`.
    arrayEach(['initial', 'rest'], function(methodName, index) {
      var dropName = 'drop' + (index ? '' : 'Right');

      LazyWrapper.prototype[methodName] = function() {
        return this[dropName](1);
      };
    });

    // Add `LazyWrapper` methods for `_.pluck` and `_.where`.
    arrayEach(['pluck', 'where'], function(methodName, index) {
      var operationName = index ? 'filter' : 'map',
          createCallback = index ? baseMatches : property;

      LazyWrapper.prototype[methodName] = function(value) {
        return this[operationName](createCallback(value));
      };
    });

    LazyWrapper.prototype.compact = function() {
      return this.filter(identity);
    };

    LazyWrapper.prototype.reject = function(predicate, thisArg) {
      predicate = getCallback(predicate, thisArg, 1);
      return this.filter(function(value) {
        return !predicate(value);
      });
    };

    LazyWrapper.prototype.slice = function(start, end) {
      start = start == null ? 0 : (+start || 0);
      var result = start < 0 ? this.takeRight(-start) : this.drop(start);

      if (end !== undefined) {
        end = (+end || 0);
        result = end < 0 ? result.dropRight(-end) : result.take(end - start);
      }
      return result;
    };

    LazyWrapper.prototype.toArray = function() {
      return this.drop(0);
    };

    // Add `LazyWrapper` methods to `lodash.prototype`.
    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
      var lodashFunc = lodash[methodName];
      if (!lodashFunc) {
        return;
      }
      var checkIteratee = /^(?:filter|map|reject)|While$/.test(methodName),
          retUnwrapped = /^(?:first|last)$/.test(methodName);

      lodash.prototype[methodName] = function() {
        var args = arguments,
            length = args.length,
            chainAll = this.__chain__,
            value = this.__wrapped__,
            isHybrid = !!this.__actions__.length,
            isLazy = value instanceof LazyWrapper,
            iteratee = args[0],
            useLazy = isLazy || isArray(value);

        if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
          // avoid lazy use if the iteratee has a "length" value other than `1`
          isLazy = useLazy = false;
        }
        var onlyLazy = isLazy && !isHybrid;
        if (retUnwrapped && !chainAll) {
          return onlyLazy
            ? func.call(value)
            : lodashFunc.call(lodash, this.value());
        }
        var interceptor = function(value) {
          var otherArgs = [value];
          push.apply(otherArgs, args);
          return lodashFunc.apply(lodash, otherArgs);
        };
        if (useLazy) {
          var wrapper = onlyLazy ? value : new LazyWrapper(this),
              result = func.apply(wrapper, args);

          if (!retUnwrapped && (isHybrid || result.__actions__)) {
            var actions = result.__actions__ || (result.__actions__ = []);
            actions.push({ 'func': thru, 'args': [interceptor], 'thisArg': lodash });
          }
          return new LodashWrapper(result, chainAll);
        }
        return this.thru(interceptor);
      };
    });

    // Add `Array` and `String` methods to `lodash.prototype`.
    arrayEach(['concat', 'join', 'pop', 'push', 'replace', 'shift', 'sort', 'splice', 'split', 'unshift'], function(methodName) {
      var func = (/^(?:replace|split)$/.test(methodName) ? stringProto : arrayProto)[methodName],
          chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
          retUnwrapped = /^(?:join|pop|replace|shift)$/.test(methodName);

      lodash.prototype[methodName] = function() {
        var args = arguments;
        if (retUnwrapped && !this.__chain__) {
          return func.apply(this.value(), args);
        }
        return this[chainName](function(value) {
          return func.apply(value, args);
        });
      };
    });

    // Map minified function names to their real names.
    baseForOwn(LazyWrapper.prototype, function(func, methodName) {
      var lodashFunc = lodash[methodName];
      if (lodashFunc) {
        var key = lodashFunc.name,
            names = realNames[key] || (realNames[key] = []);

        names.push({ 'name': methodName, 'func': lodashFunc });
      }
    });

    realNames[createHybridWrapper(null, BIND_KEY_FLAG).name] = [{ 'name': 'wrapper', 'func': null }];

    // Add functions to the lazy wrapper.
    LazyWrapper.prototype.clone = lazyClone;
    LazyWrapper.prototype.reverse = lazyReverse;
    LazyWrapper.prototype.value = lazyValue;

    // Add chaining functions to the `lodash` wrapper.
    lodash.prototype.chain = wrapperChain;
    lodash.prototype.commit = wrapperCommit;
    lodash.prototype.plant = wrapperPlant;
    lodash.prototype.reverse = wrapperReverse;
    lodash.prototype.toString = wrapperToString;
    lodash.prototype.run = lodash.prototype.toJSON = lodash.prototype.valueOf = lodash.prototype.value = wrapperValue;

    // Add function aliases to the `lodash` wrapper.
    lodash.prototype.collect = lodash.prototype.map;
    lodash.prototype.head = lodash.prototype.first;
    lodash.prototype.select = lodash.prototype.filter;
    lodash.prototype.tail = lodash.prototype.rest;

    return lodash;
  }

  /*--------------------------------------------------------------------------*/

  // Export lodash.
  var _ = runInContext();

  // Some AMD build optimizers like r.js check for condition patterns like the following:
  if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
    // Expose lodash to the global object when an AMD loader is present to avoid
    // errors in cases where lodash is loaded by a script tag and not intended
    // as an AMD module. See http://requirejs.org/docs/errors.html#mismatch for
    // more details.
    root._ = _;

    // Define as an anonymous module so, through path mapping, it can be
    // referenced as the "underscore" module.
    define(function() {
      return _;
    });
  }
  // Check for `exports` after `define` in case a build optimizer adds an `exports` object.
  else if (freeExports && freeModule) {
    // Export for Node.js or RingoJS.
    if (moduleExports) {
      (freeModule.exports = _)._ = _;
    }
    // Export for Narwhal or Rhino -require.
    else {
      freeExports._ = _;
    }
  }
  else {
    // Export for a browser or Rhino.
    root._ = _;
  }
}.call(this));

}).call(this,typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{}],5:[function(require,module,exports){
(function (process,global){
'use strict';
/**
 * Module dependencies
 */
/*global setImmediate:true*/
var events = require('events'),
  Store = require('./store'),
  eos = require('end-of-stream'),
  mqttPacket = require('mqtt-packet'),
  Writable = require('readable-stream').Writable,
  inherits = require('inherits'),
  setImmediate = global.setImmediate || function (callback) {
    // works in node v0.8
    process.nextTick(callback);
  },
  defaultConnectOptions = {
    keepalive: 10,
    protocolId: 'MQTT',
    protocolVersion: 4,
    reconnectPeriod: 1000,
    clean: true
  };

function defaultId () {
  return 'mqttjs_' + Math.random().toString(16).substr(2, 8);
}

function sendPacket (client, packet, cb) {
  try {
    var buf = mqttPacket.generate(packet);
    if (!client.stream.write(buf) && cb) {
      client.stream.once('drain', cb);
    } else if (cb) {
      cb();
    }
  } catch (err) {
    if (cb) {
      cb(err);
    } else {
      client.emit('error', err);
    }
  }
}

function storeAndSend (client, packet, cb) {
  client.outgoingStore.put(packet, function storedPacket (err) {
    if (err) {
      return cb && cb(err);
    }
    sendPacket(client, packet, cb);
  });
}

function nop () {}

/**
 * MqttClient constructor
 *
 * @param {Stream} stream - stream
 * @param {Object} [options] - connection options
 * (see Connection#connect)
 */
function MqttClient (streamBuilder, options) {
  var k,
    that = this;

  if (!(this instanceof MqttClient)) {
    return new MqttClient(streamBuilder, options);
  }

  this.options = options || {};

  // Defaults
  for (k in defaultConnectOptions) {
    if ('undefined' === typeof this.options[k]) {
      this.options[k] = defaultConnectOptions[k];
    } else {
      this.options[k] = options[k];
    }
  }

  this.options.clientId = this.options.clientId || defaultId();

  this.streamBuilder = streamBuilder;

  // Inflight message storages
  this.outgoingStore = this.options.outgoingStore || new Store();
  this.incomingStore = this.options.incomingStore || new Store();

  // Ping timer, setup in _setupPingTimer
  this.pingTimer = null;
  // Is the client connected?
  this.connected = false;
  // Are we disconnecting?
  this.disconnecting = false;
  // Packet queue
  this.queue = [];
  // Are we intentionally disconnecting?
  this.disconnecting = false;
  // Reconnect timer
  this.reconnectTimer = null;
  // MessageIDs starting with 1
  this.nextId = Math.floor(Math.random() * 65535);

  // Inflight callbacks
  this.outgoing = {};

  // Mark connected on connect
  this.on('connect', function () {
    this.connected = true;
  });

  // Mark disconnected on stream close
  this.on('close', function () {
    this.connected = false;
  });

  // Setup ping timer
  this.on('connect', this._setupPingTimer);

  // Send queued packets
  this.on('connect', function () {
    var queue = this.queue;

    function deliver () {
      var entry = queue.shift(),
        packet = null;

      if (!entry) {
        return;
      }

      packet = entry.packet;

      that._sendPacket(
        packet,
        function (err) {
          if (entry.cb) {
            entry.cb(err);
          }
          deliver();
        }
      );
    }

    deliver();
  });


  // Clear ping timer
  this.on('close', function () {
    if (null !== that.pingTimer) {
      clearInterval(that.pingTimer);
      that.pingTimer = null;
    }
  });

  // Setup reconnect timer on disconnect
  this.on('close', this._setupReconnect);

  events.EventEmitter.call(this);

  this._setupStream();
}
inherits(MqttClient, events.EventEmitter);

/**
 * setup the event handlers in the inner stream.
 *
 * @api private
 */
MqttClient.prototype._setupStream = function () {
  var connectPacket,
    that = this,
    writable = new Writable(),
    parser = mqttPacket.parser(this.options),
    completeParse = null,
    packets = [];

  this._clearReconnect();

  this.stream = this.streamBuilder(this);

  parser.on('packet', function (packet) {
    packets.push(packet);
  });

  function process () {
    var packet = packets.shift(),
      done = completeParse;
    if (packet) {
      that._handlePacket(packet, process);
    } else {
      completeParse = null;
      done();
    }
  }

  writable._write = function (buf, enc, done) {
    completeParse = done;
    parser.parse(buf);
    process();
  };

  this.stream.pipe(writable);

  // Suppress connection errors
  this.stream.on('error', nop);

  // Echo stream close
  eos(this.stream, this.emit.bind(this, 'close'));

  // Send a connect packet
  connectPacket = Object.create(this.options);
  connectPacket.cmd = 'connect';
  // avoid message queue
  sendPacket(this, connectPacket);

  // Echo connection errors
  parser.on('error', this.emit.bind(this, 'error'));

  this.outgoingStore
    .createStream()
    .on('data', function (packet) {
      that._sendPacket(packet);
    })
    .on('error', this.emit.bind(this, 'error'));
};

MqttClient.prototype._handlePacket = function (packet, done) {
  switch (packet.cmd) {
    case 'publish':
      this._handlePublish(packet, done);
      break;
    case 'puback':
    case 'pubrec':
    case 'pubcomp':
    case 'suback':
    case 'unsuback':
      this._handleAck(packet);
      done();
      break;
    case 'pubrel':
      this._handlePubrel(packet, done);
      break;
    case 'connack':
      this._handleConnack(packet);
      done();
      break;
    case 'pingresp':
      this._handlePingresp(packet);
      done();
      break;
    default:
      // do nothing
      // maybe we should do an error handling
      // or just log it
      break;
  }
};

MqttClient.prototype._checkDisconnecting = function (callback) {
  if (this.disconnecting) {
    if (callback) {
      callback(new Error('client disconnecting'));
    } else {
      this.emit(new Error('client disconnecting'));
    }
  }
  return this.disconnecting;
};

/**
 * publish - publish <message> to <topic>
 *
 * @param {String} topic - topic to publish to
 * @param {String, Buffer} message - message to publish
 * @param {Object} [opts] - publish options, includes:
 *    {Number} qos - qos level to publish on
 *    {Boolean} retain - whether or not to retain the message
 * @param {Function} [callback] - function(err){}
 *    called when publish succeeds or fails
 * @returns {MqttClient} this - for chaining
 * @api public
 *
 * @example client.publish('topic', 'message');
 * @example
 *     client.publish('topic', 'message', {qos: 1, retain: true});
 * @example client.publish('topic', 'message', console.log);
 */
MqttClient.prototype.publish = function (topic, message, opts, callback) {
  var packet;

  // .publish(topic, payload, cb);
  if ('function' === typeof opts) {
    callback = opts;
    opts = null;
  }

  // Default opts
  if (!opts) {
    opts = {qos: 0, retain: false};
  }

  if (this._checkDisconnecting(callback)) {
    return this;
  }

  callback = callback || nop;

  packet = {
    cmd: 'publish',
    topic: topic,
    payload: message,
    qos: opts.qos,
    retain: opts.retain,
    messageId: this._nextId()
  };

  switch (opts.qos) {
    case 1:
    case 2:
      // Add to callbacks
      this.outgoing[packet.messageId] = callback;
      this._sendPacket(packet);
      break;
    default:
      this._sendPacket(packet, callback);
      break;
  }

  return this;
};

/**
 * subscribe - subscribe to <topic>
 *
 * @param {String, Array, Object} topic - topic(s) to subscribe to, supports objects in the form {'topic': qos}
 * @param {Object} [opts] - optional subscription options, includes:
 *    {Number} qos - subscribe qos level
 * @param {Function} [callback] - function(err, granted){} where:
 *    {Error} err - subscription error (none at the moment!)
 *    {Array} granted - array of {topic: 't', qos: 0}
 * @returns {MqttClient} this - for chaining
 * @api public
 * @example client.subscribe('topic');
 * @example client.subscribe('topic', {qos: 1});
 * @example client.subscribe({'topic': 0, 'topic2': 1}, console.log);
 * @example client.subscribe('topic', console.log);
 */
MqttClient.prototype.subscribe = function () {
  var packet,
    args = Array.prototype.slice.call(arguments),
    subs = [],
    obj = args.shift(),
    callback = args.pop() || nop,
    opts = args.pop();

  if ('string' === typeof obj) {
    obj = [obj];
  }

  if (this._checkDisconnecting(callback)) {
    return this;
  }

  if ('function' !== typeof callback) {
    opts = callback;
    callback = nop;
  }

  if (!opts) {
    opts = { qos: 0 };
  }

  if (Array.isArray(obj)) {
    obj.forEach(function (topic) {
      subs.push({
        topic: topic,
        qos: opts.qos
      });
    });
  } else {
    Object
      .keys(obj)
      .forEach(function (k) {
        subs.push({
          topic: k,
          qos: obj[k]
        });
      });
  }

  packet = {
    cmd: 'subscribe',
    subscriptions: subs,
    qos: 1,
    retain: false,
    dup: false,
    messageId: this._nextId()
  };

  this.outgoing[packet.messageId] = callback;

  this._sendPacket(packet);

  return this;
};

/**
 * unsubscribe - unsubscribe from topic(s)
 *
 * @param {String, Array} topic - topics to unsubscribe from
 * @param {Function} [callback] - callback fired on unsuback
 * @returns {MqttClient} this - for chaining
 * @api public
 * @example client.unsubscribe('topic');
 * @example client.unsubscribe('topic', console.log);
 */
MqttClient.prototype.unsubscribe = function (topic, callback) {
  var packet = {
    cmd: 'unsubscribe',
    qos: 1,
    messageId: this._nextId()
  };

  callback = callback || nop;

  if (this._checkDisconnecting(callback)) {
    return this;
  }

  if ('string' === typeof topic) {
    packet.unsubscriptions = [topic];
  } else if ('object' === typeof topic && topic.length) {
    packet.unsubscriptions = topic;
  }

  this.outgoing[packet.messageId] = callback;

  this._sendPacket(packet);

  return this;
};

/**
 * end - close connection
 *
 * @returns {MqttClient} this - for chaining
 * @api public
 */
MqttClient.prototype.end = function (cb) {
  var that = this;

  function closeStores () {
    that.incomingStore.close(function () {
      that.outgoingStore.close(cb);
    });
  }

  function finish () {
    that._cleanUp(false, closeStores);
  }

  if (this.disconnecting) {
    return true;
  }

  this.disconnecting = true;

  if (0 < Object.keys(this.outgoing).length) {
    // wait 10ms, just to be sure we received all of it
    this.once('outgoingEmpty', setTimeout.bind(null, finish, 10));
  } else {
    finish();
  }

  return this;
};

/**
 * _reconnect - implement reconnection
 * @api privateish
 */
MqttClient.prototype._reconnect = function () {
  this.emit('reconnect');
  this._setupStream();
};

/**
 * _setupReconnect - setup reconnect timer
 */
MqttClient.prototype._setupReconnect = function () {
  var that = this;

  if (!that.disconnecting && !that.reconnectTimer && (0 < that.options.reconnectPeriod)) {
    this.emit('offline');
    that.reconnectTimer = setInterval(function () {
      that._reconnect();
    }, that.options.reconnectPeriod);
  }
};

/**
 * _clearReconnect - clear the reconnect timer
 */
MqttClient.prototype._clearReconnect = function () {
  if (this.reconnectTimer) {
    clearInterval(this.reconnectTimer);
    this.reconnectTimer = false;
  }
};


/**
 * _cleanUp - clean up on connection end
 * @api private
 */
MqttClient.prototype._cleanUp = function (forced, done) {
  if (done) {
    this.stream.on('close', done);
  }

  if (forced) {
    this.stream.destroy();
  } else {
    this._sendPacket(
      { cmd: 'disconnect' },
      setImmediate.bind(
        null,
        this.stream.end.bind(this.stream)
      )
    );
  }

  this._clearReconnect();

  if (null !== this.pingTimer) {
    clearInterval(this.pingTimer);
    this.pingTimer = null;
  }
};

/**
 * _sendPacket - send or queue a packet
 * @param {String} type - packet type (see `protocol`)
 * @param {Object} packet - packet options
 * @param {Function} cb - callback when the packet is sent
 * @api private
 */
MqttClient.prototype._sendPacket = function (packet, cb) {
  if (!this.connected) {
    return this.queue.push({ packet: packet, cb: cb });
  }

  switch (packet.qos) {
    case 2:
    case 1:
      storeAndSend(this, packet, cb);
      break;
    /**
     * no need of case here since it will be caught by default
     * and jshint comply that before default it must be a break
     * anyway it will result in -1 evaluation
     */
    case 0:
      /* falls through */
    default:
      sendPacket(this, packet, cb);
      break;
  }
};

/**
 * _setupPingTimer - setup the ping timer
 *
 * @api private
 */
MqttClient.prototype._setupPingTimer = function () {
  var that = this;

  if (!this.pingTimer && this.options.keepalive) {
    this.pingResp = true;
    this.pingTimer = setInterval(function () {
      that._checkPing();
    }, this.options.keepalive * 1000);
  }
};

/**
 * _checkPing - check if a pingresp has come back, and ping the server again
 *
 * @api private
 */
MqttClient.prototype._checkPing = function () {
  if (this.pingResp) {
    this.pingResp = false;
    this._sendPacket({ cmd: 'pingreq' });
  } else {
    // do a forced cleanup since socket will be in bad shape
    this._cleanUp(true);
  }
};

/**
 * _handlePingresp - handle a pingresp
 *
 * @api private
 */
MqttClient.prototype._handlePingresp = function () {
  this.pingResp = true;
};

/**
 * _handleConnack
 *
 * @param {Object} packet
 * @api private
 */

MqttClient.prototype._handleConnack = function (packet) {
  var rc = packet.returnCode,
    // TODO: move to protocol
    errors = [
      '',
      'Unacceptable protocol version',
      'Identifier rejected',
      'Server unavailable',
      'Bad username or password',
      'Not authorized'
    ];

  if (0 === rc) {
    this.emit('connect');
  } else if (0 < rc) {
    this.emit('error',
        new Error('Connection refused: ' + errors[rc]));
  }
};

/**
 * _handlePublish
 *
 * @param {Object} packet
 * @api private
 */
/*
those late 2 case should be rewrite to comply with coding style:

case 1:
case 0:
  // do not wait sending a puback
  // no callback passed
  if (1 === qos) {
    this._sendPacket({
      cmd: 'puback',
      messageId: mid
    });
  }
  // emit the message event for both qos 1 and 0
  this.emit('message', topic, message, packet);
  this.handleMessage(packet, done);
  break;
default:
  // do nothing but every switch mus have a default
  // log or throw an error about unknown qos
  break;

for now i just suppressed the warnings
*/
MqttClient.prototype._handlePublish = function (packet, done) {
  var topic = packet.topic.toString(),
    message = packet.payload,
    qos = packet.qos,
    mid = packet.messageId,
    that = this;

  switch (qos) {
    case 2:
      this.incomingStore.put(packet, function () {
        that._sendPacket({cmd: 'pubrec', messageId: mid}, done);
      });
      break;
    case 1:
      // do not wait sending a puback
      // no callback passed
      this._sendPacket({
        cmd: 'puback',
        messageId: mid
      });
      /* falls through */
    case 0:
      // emit the message event for both qos 1 and 0
      this.emit('message', topic, message, packet);
      this.handleMessage(packet, done);
      break;
    default:
      // do nothing
      // log or throw an error about unknown qos
      break;
  }
};

/**
 * Handle messages with backpressure support, one at a time.
 * Override at will.
 *
 * @param Packet packet the packet
 * @param Function callback call when finished
 * @api public
 */
MqttClient.prototype.handleMessage = function (packet, callback) {
  callback();
};

/**
 * _handleAck
 *
 * @param {Object} packet
 * @api private
 */

MqttClient.prototype._handleAck = function (packet) {
  var mid = packet.messageId,
    type = packet.cmd,
    response = null,
    cb = this.outgoing[mid],
    that = this;

  if (!cb) {
    // Server sent an ack in error, ignore it.
    return;
  }

  // Process
  switch (type) {
    case 'pubcomp':
      // same thing as puback for QoS 2
    case 'puback':
      // Callback - we're done
      delete this.outgoing[mid];
      this.outgoingStore.del(packet, cb);
      break;
    case 'pubrec':
      response = {
        cmd: 'pubrel',
        qos: 2,
        messageId: mid
      };

      this._sendPacket(response);
      break;
    case 'suback':
      delete this.outgoing[mid];
      this.outgoingStore.del(packet, function (err, original) {
        var i,
          origSubs = original.subscriptions,
          granted = packet.granted;

        if (err) {
          // missing packet, what should we do?
          return that.emit('error', err);
        }

        for (i = 0; i < granted.length; i += 1) {
          origSubs[i].qos = granted[i];
        }

        cb(null, origSubs);
      });
      break;
    case 'unsuback':
      delete this.outgoing[mid];
      this.outgoingStore.del(packet, cb);
      break;
    default:
      that.emit('error', new Error('unrecognized packet type'));
  }

  if (this.disconnecting &&
      0 === Object.keys(this.outgoing).length) {
    this.emit('outgoingEmpty');
  }
};

/**
 * _handlePubrel
 *
 * @param {Object} packet
 * @api private
 */

MqttClient.prototype._handlePubrel = function (packet, callback) {
  var mid = packet.messageId,
    that = this;

  that.incomingStore.get(packet, function (err, pub) {
    if (err) {
      return that.emit('error', err);
    }

    if ('pubrel' !== pub.cmd) {
      that.emit('message', pub.topic, pub.payload, pub);
      that.incomingStore.put(packet);
    }

    that._sendPacket({cmd: 'pubcomp', messageId: mid}, callback);
  });
};

/**
 * _nextId
 */
MqttClient.prototype._nextId = function () {
  var id = this.nextId++;
  // Ensure 16 bit unsigned int:
  if (65535 === id) {
    this.nextId = 1;
  }
  return id;
};

module.exports = MqttClient;

}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./store":6,"_process":37,"end-of-stream":7,"events":34,"inherits":10,"mqtt-packet":13,"readable-stream":26}],6:[function(require,module,exports){
'use strict';
var PassThrough = require('readable-stream').PassThrough,
  streamsOpts = { objectMode: true };

/**
 * In-memory implementation of the message store
 * This can actually be saved into files.
 *
 */
function Store () {
  if (!(this instanceof Store)) {
    return new Store();
  }

  this._inflights = {};
}

/**
 * Adds a packet to the store, a packet is
 * anything that has a messageId property.
 *
 */
Store.prototype.put = function (packet, cb) {
  this._inflights[packet.messageId] = packet;

  if (cb) {
    cb();
  }

  return this;
};

/**
 * Creates a stream with all the packets in the store
 *
 */
Store.prototype.createStream = function () {
  var stream = new PassThrough(streamsOpts),
    ids = Object.keys(this._inflights),
    i = 0;

  for (i = 0; i < ids.length; i++) {
    stream.write(this._inflights[ids[i]]);
  }

  stream.end();

  return stream;
};

/**
 * deletes a packet from the store.
 */
Store.prototype.del = function (packet, cb) {
  packet = this._inflights[packet.messageId];
  if (packet) {
    delete this._inflights[packet.messageId];
    cb(null, packet);
  } else if (cb) {
    cb(new Error('missing packet'));
  }

  return this;
};

/**
 * get a packet from the store.
 */
Store.prototype.get = function (packet, cb) {
  packet = this._inflights[packet.messageId];
  if (packet) {
    cb(null, packet);
  } else if (cb) {
    cb(new Error('missing packet'));
  }

  return this;
};

/**
 * Close the store
 */
Store.prototype.close = function (cb) {
  this._inflights = null;
  if (cb) {
    cb();
  }
};

module.exports = Store;

},{"readable-stream":26}],7:[function(require,module,exports){
var once = require('once');

var noop = function() {};

var isRequest = function(stream) {
	return stream.setHeader && typeof stream.abort === 'function';
};

var isChildProcess = function(stream) {
	return stream.stdio && Array.isArray(stream.stdio) && stream.stdio.length === 3
};

var eos = function(stream, opts, callback) {
	if (typeof opts === 'function') return eos(stream, null, opts);
	if (!opts) opts = {};

	callback = once(callback || noop);

	var ws = stream._writableState;
	var rs = stream._readableState;
	var readable = opts.readable || (opts.readable !== false && stream.readable);
	var writable = opts.writable || (opts.writable !== false && stream.writable);

	var onlegacyfinish = function() {
		if (!stream.writable) onfinish();
	};

	var onfinish = function() {
		writable = false;
		if (!readable) callback();
	};

	var onend = function() {
		readable = false;
		if (!writable) callback();
	};

	var onexit = function(exitCode) {
		callback(exitCode ? new Error('exited with error code: ' + exitCode) : null);
	};

	var onclose = function() {
		if (readable && !(rs && rs.ended)) return callback(new Error('premature close'));
		if (writable && !(ws && ws.ended)) return callback(new Error('premature close'));
	};

	var onrequest = function() {
		stream.req.on('finish', onfinish);
	};

	if (isRequest(stream)) {
		stream.on('complete', onfinish);
		stream.on('abort', onclose);
		if (stream.req) onrequest();
		else stream.on('request', onrequest);
	} else if (writable && !ws) { // legacy streams
		stream.on('end', onlegacyfinish);
		stream.on('close', onlegacyfinish);
	}

	if (isChildProcess(stream)) stream.on('exit', onexit);

	stream.on('end', onend);
	stream.on('finish', onfinish);
	if (opts.error !== false) stream.on('error', callback);
	stream.on('close', onclose);

	return function() {
		stream.removeListener('complete', onfinish);
		stream.removeListener('abort', onclose);
		stream.removeListener('request', onrequest);
		if (stream.req) stream.req.removeListener('finish', onfinish);
		stream.removeListener('end', onlegacyfinish);
		stream.removeListener('close', onlegacyfinish);
		stream.removeListener('finish', onfinish);
		stream.removeListener('exit', onexit);
		stream.removeListener('end', onend);
		stream.removeListener('error', callback);
		stream.removeListener('close', onclose);
	};
};

module.exports = eos;
},{"once":9}],8:[function(require,module,exports){
// Returns a wrapper function that returns a wrapped callback
// The wrapper function should do some stuff, and return a
// presumably different callback function.
// This makes sure that own properties are retained, so that
// decorations and such are not lost along the way.
module.exports = wrappy
function wrappy (fn, cb) {
  if (fn && cb) return wrappy(fn)(cb)

  if (typeof fn !== 'function')
    throw new TypeError('need wrapper function')

  Object.keys(fn).forEach(function (k) {
    wrapper[k] = fn[k]
  })

  return wrapper

  function wrapper() {
    var args = new Array(arguments.length)
    for (var i = 0; i < args.length; i++) {
      args[i] = arguments[i]
    }
    var ret = fn.apply(this, args)
    var cb = args[args.length-1]
    if (typeof ret === 'function' && ret !== cb) {
      Object.keys(cb).forEach(function (k) {
        ret[k] = cb[k]
      })
    }
    return ret
  }
}

},{}],9:[function(require,module,exports){
var wrappy = require('wrappy')
module.exports = wrappy(once)

once.proto = once(function () {
  Object.defineProperty(Function.prototype, 'once', {
    value: function () {
      return once(this)
    },
    configurable: true
  })
})

function once (fn) {
  var f = function () {
    if (f.called) return f.value
    f.called = true
    return f.value = fn.apply(this, arguments)
  }
  f.called = false
  return f
}

},{"wrappy":8}],10:[function(require,module,exports){
if (typeof Object.create === 'function') {
  // implementation from standard node.js 'util' module
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  };
} else {
  // old school shim for old browsers
  module.exports = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor
    var TempCtor = function () {}
    TempCtor.prototype = superCtor.prototype
    ctor.prototype = new TempCtor()
    ctor.prototype.constructor = ctor
  }
}

},{}],11:[function(require,module,exports){
/* Protocol - protocol constants */

/* Command code => mnemonic */
module.exports.types = {
  0: 'reserved',
  1: 'connect',
  2: 'connack',
  3: 'publish',
  4: 'puback',
  5: 'pubrec',
  6: 'pubrel',
  7: 'pubcomp',
  8: 'subscribe',
  9: 'suback',
  10: 'unsubscribe',
  11: 'unsuback',
  12: 'pingreq',
  13: 'pingresp',
  14: 'disconnect',
  15: 'reserved'
};

/* Mnemonic => Command code */
module.exports.codes = {}
for(var k in module.exports.types) {
  var v = module.exports.types[k];
  module.exports.codes[v] = k;
}

/* Header */
module.exports.CMD_SHIFT = 4;
module.exports.CMD_MASK = 0xF0;
module.exports.DUP_MASK = 0x08;
module.exports.QOS_MASK = 0x03;
module.exports.QOS_SHIFT = 1;
module.exports.RETAIN_MASK = 0x01;

/* Length */
module.exports.LENGTH_MASK = 0x7F;
module.exports.LENGTH_FIN_MASK = 0x80;

/* Connack */
module.exports.SESSIONPRESENT_MASK = 0x01;

/* Connect */
module.exports.USERNAME_MASK = 0x80;
module.exports.PASSWORD_MASK = 0x40;
module.exports.WILL_RETAIN_MASK = 0x20;
module.exports.WILL_QOS_MASK = 0x18;
module.exports.WILL_QOS_SHIFT = 3;
module.exports.WILL_FLAG_MASK = 0x04;
module.exports.CLEAN_SESSION_MASK = 0x02;

},{}],12:[function(require,module,exports){
(function (Buffer){

'use strict';

var protocol = require('./constants')
  , empty = new Buffer(0)

function generate(packet) {

  switch(packet.cmd) {
    case 'connect':
      return connect(packet)
    case 'connack':
      return connack(packet)
    case 'publish':
      return publish(packet)
    case 'puback':
    case 'pubrec':
    case 'pubrel':
    case 'pubcomp':
    case 'unsuback':
      return confirmation(packet)
    case 'subscribe':
      return subscribe(packet)
    case 'suback':
      return suback(packet)
    case 'unsubscribe':
      return unsubscribe(packet)
    case 'pingreq':
    case 'pingresp':
    case 'disconnect':
      return emptyPacket(packet)
    default:
      throw new Error('unknown command')
  }
}

function connect(opts) {
  var opts = opts || {}
    , protocolId = opts.protocolId || 'MQTT'
    , protocolVersion = opts.protocolVersion || 4
    , will = opts.will
    , clean = opts.clean
    , keepalive = opts.keepalive || 0
    , clientId = opts.clientId
    , username = opts.username
    , password = opts.password

  if (clean === undefined) {
    clean = true
  }

  var length = 0

  // Must be a string and non-falsy
  if(!protocolId ||
     (typeof protocolId !== "string" && !Buffer.isBuffer(protocolId))) {
    throw new Error('Invalid protocol id')
  } else {
    length += protocolId.length + 2
  }

  // Must be a 1 byte number
  if (!protocolVersion ||
      'number' !== typeof protocolVersion ||
      protocolVersion > 255 ||
      protocolVersion < 0) {

    throw new Error('Invalid protocol version')
  } else {
    length += 1
  }

  // Must be a non-falsy string
  if(!clientId ||
     (typeof clientId !== "string" && !Buffer.isBuffer(clientId))) {
    throw new Error('Invalid client id')
  } else {
    length += clientId.length + 2
  }

  // Must be a two byte number
  if ('number' !== typeof keepalive ||
      keepalive < 0 ||
      keepalive > 65535) {
    throw new Error('Invalid keepalive')
  } else {
    length += 2
  }

  // Connect flags
  length += 1

  // If will exists...
  if (will) {
    // It must be an object
    if ('object' !== typeof will) {
      throw new Error('Invalid will')
    }
    // It must have topic typeof string
    if (!will.topic || 'string' !== typeof will.topic) {
      throw new Error('Invalid will topic')
    } else {
      length += will.topic.length + 2
    }

    // Payload
    if (will.payload && will.payload) {
      if (will.payload.length >= 0) {
        if ('string' === typeof will.payload) {
          length += Buffer.byteLength(will.payload) + 2
        } else {
          length += will.payload.length + 2
        }
      } else {
        throw new Error('Invalid will payload')
      }
    } else {
      length += 2
    }
  }

  // Username
  if (username) {
    if (username.length) {
      length += username.length + 2
    } else {
      throw new Error('Invalid username')
    }
  }

  // Password
  if (password) {
    if (password.length) {
      length += password.length + 2
    } else {
      throw new Error('Invalid password')
    }
  }

  var buffer = new Buffer(1 + calcLengthLength(length) + length)
    , pos = 0

  // Generate header
  buffer.writeUInt8(protocol.codes['connect'] << protocol.CMD_SHIFT, pos++)

  // Generate length
  pos += writeLength(buffer, pos, length)

  // Generate protocol ID
  pos += writeStringOrBuffer(buffer, pos, protocolId)
  buffer.writeUInt8(protocolVersion, pos++)

  // Connect flags
  var flags = 0
  flags |= username ? protocol.USERNAME_MASK : 0
  flags |= password ? protocol.PASSWORD_MASK : 0
  flags |= (will && will.retain) ? protocol.WILL_RETAIN_MASK : 0
  flags |= (will && will.qos) ?
    will.qos << protocol.WILL_QOS_SHIFT : 0
  flags |= will ? protocol.WILL_FLAG_MASK : 0
  flags |= clean ? protocol.CLEAN_SESSION_MASK : 0

  buffer.writeUInt8(flags, pos++)

  // Keepalive
  pos += writeNumber(buffer, pos, keepalive)

  // Client ID
  pos += writeStringOrBuffer(buffer, pos, clientId)

  // Will
  if (will) {
  	pos += writeString(buffer, pos, will.topic)
    pos += writeStringOrBuffer(buffer, pos, will.payload)
  }

  // Username and password
  if (username)
    pos += writeStringOrBuffer(buffer, pos, username)

  if (password)
    pos += writeStringOrBuffer(buffer, pos, password)

  return buffer
}

function connack(opts) {
  var opts = opts || {}
    , rc = opts.returnCode;

  // Check return code
  if ('number' !== typeof rc)
    throw new Error('Invalid return code');

  var buffer = new Buffer(4)
    , pos = 0;

  buffer.writeUInt8(protocol.codes['connack'] << protocol.CMD_SHIFT, pos++);
  pos += writeLength(buffer, pos, 2);
  buffer.writeUInt8(opts.sessionPresent && protocol.SESSIONPRESENT_MASK || 0, pos++);
  buffer.writeUInt8(rc, pos++);

  return buffer;
}

function publish(opts) {
  var opts = opts || {}
    , dup = opts.dup ? protocol.DUP_MASK : 0
    , qos = opts.qos
    , retain = opts.retain ? protocol.RETAIN_MASK : 0
    , topic = opts.topic
    , payload = opts.payload || empty
    , id = opts.messageId;

  var length = 0;

  // Topic must be a non-empty string or Buffer
  if (typeof topic === "string")
    length += Buffer.byteLength(topic) + 2;
  else if (Buffer.isBuffer(topic))
    length += topic.length + 2;
  else
    throw new Error('Invalid topic');

  // get the payload length
  if (!Buffer.isBuffer(payload)) {
    length += Buffer.byteLength(payload);
  } else {
    length += payload.length;
  }

  // Message id must a number if qos > 0
  if (qos && 'number' !== typeof id) {
    throw new Error('Invalid message id')
  } else if (qos) {
    length += 2;
  }

  var buffer = new Buffer(1 + calcLengthLength(length) + length)
    , pos = 0;

  // Header
  buffer[pos++] =
    protocol.codes['publish'] << protocol.CMD_SHIFT |
    dup |
    qos << protocol.QOS_SHIFT |
    retain;

  // Remaining length
  pos += writeLength(buffer, pos, length);

  // Topic
  pos += writeStringOrBuffer(buffer, pos, topic);

  // Message ID
  if (qos > 0) {
    pos += writeNumber(buffer, pos, id);
  }

  // Payload
  if (!Buffer.isBuffer(payload)) {
    writeStringNoPos(buffer, pos, payload);
  } else {
    writeBuffer(buffer, pos, payload);
  }

  return buffer;
}

/* Puback, pubrec, pubrel and pubcomp */
function confirmation(opts) {
  var opts = opts || {}
    , type = opts.cmd || 'puback'
    , id = opts.messageId
    , dup = (opts.dup && type === 'pubrel') ? protocol.DUP_MASK : 0
    , qos = 0

  if (type === 'pubrel')
    qos = 1
  else if (type === 'pubcomp')
    qos = 2

  // Check message ID
  if ('number' !== typeof id)
    throw new Error('Invalid message id');

  var buffer = new Buffer(4)
    , pos = 0;

  // Header
  buffer[pos++] =
    protocol.codes[type] << protocol.CMD_SHIFT |
    dup |
    qos << protocol.QOS_SHIFT;

  // Length
  pos += writeLength(buffer, pos, 2);

  // Message ID
  pos += writeNumber(buffer, pos, id);

  return buffer;
}

function subscribe(opts) {
  var opts = opts || {}
    , dup = opts.dup ? protocol.DUP_MASK : 0
    , qos = opts.qos || 0
    , id = opts.messageId
    , subs = opts.subscriptions;

  var length = 0;

  // Check mid
  if ('number' !== typeof id) {
    throw new Error('Invalid message id');
  } else {
    length += 2;
  }
  // Check subscriptions
  if ('object' === typeof subs && subs.length) {
    for (var i = 0; i < subs.length; i += 1) {
      var topic = subs[i].topic
        , qos = subs[i].qos;

      if ('string' !== typeof topic) {
        throw new Error('Invalid subscriptions - invalid topic');
      }
      if ('number' !== typeof qos) {
        throw new Error('Invalid subscriptions - invalid qos');
      }

      length += Buffer.byteLength(topic) + 2 + 1;
    }
  } else {
    throw new Error('Invalid subscriptions');
  }

  var buffer = new Buffer(1 + calcLengthLength(length) + length)
    , pos = 0;

  // Generate header
  buffer.writeUInt8(
    protocol.codes['subscribe'] << protocol.CMD_SHIFT |
    dup |
    1 << protocol.QOS_SHIFT, pos++);

  // Generate length
  pos += writeLength(buffer, pos, length);

  // Generate message ID
  pos += writeNumber(buffer, pos, id);

  // Generate subs
  for (var i = 0; i < subs.length; i++) {
    var sub = subs[i]
      , topic = sub.topic
      , qos = sub.qos;

    // Write topic string
    pos += writeString(buffer, pos, topic);
    // Write qos
    buffer.writeUInt8(qos, pos++);
  }

  return buffer;
}

function suback(opts) {
  var opts = opts || {}
    , id = opts.messageId
    , granted = opts.granted;

  var length = 0;

  // Check message id
  if ('number' !== typeof id) {
    throw new Error('Invalid message id');
  } else {
    length += 2;
  }
  // Check granted qos vector
  if ('object' === typeof granted && granted.length) {
    for (var i = 0; i < granted.length; i += 1) {
      if ('number' !== typeof granted[i]) {
        throw new Error('Invalid qos vector');
      }
      length += 1;
    }
  } else {
    throw new Error('Invalid qos vector');
  }

  var buffer = new Buffer(1 + calcLengthLength(length) + length)
    , pos = 0;

  // Header
  buffer.writeUInt8(protocol.codes['suback'] << protocol.CMD_SHIFT, pos++);

  // Length
  pos += writeLength(buffer, pos, length);

  // Message ID
  pos += writeNumber(buffer, pos, id);

  // Subscriptions
  for (var i = 0; i < granted.length; i++) {
    buffer.writeUInt8(granted[i], pos++);
  }

  return buffer;
}

function unsubscribe(opts) {
  var opts = opts || {}
    , id = opts.messageId
    , dup = opts.dup ? protocol.DUP_MASK : 0
    , unsubs = opts.unsubscriptions;

  var length = 0;

  // Check message id
  if ('number' !== typeof id) {
    throw new Error('Invalid message id');
  } else {
    length += 2;
  }
  // Check unsubs
  if ('object' === typeof unsubs && unsubs.length) {
    for (var i = 0; i < unsubs.length; i += 1) {
      if ('string' !== typeof unsubs[i]) {
        throw new Error('Invalid unsubscriptions');
      }
      length += Buffer.byteLength(unsubs[i]) + 2;
    }
  } else {
    throw new Error('Invalid unsubscriptions');
  }

  var buffer = new Buffer(1 + calcLengthLength(length) + length)
    , pos = 0;

  // Header
  buffer[pos++] =
    protocol.codes['unsubscribe'] << protocol.CMD_SHIFT |
    dup |
    1 << protocol.QOS_SHIFT;

  // Length
  pos += writeLength(buffer, pos, length);

  // Message ID
  pos += writeNumber(buffer, pos, id);

  // Unsubs
  for (var i = 0; i < unsubs.length; i++) {
    pos += writeString(buffer, pos, unsubs[i]);
  }

  return buffer;
}

function emptyPacket(opts) {
  var buf = new Buffer(2);
  buf[0] = protocol.codes[opts.cmd] << 4;
  buf[1] = 0;
  return buf;
}

/**
 * calcLengthLength - calculate the length of the remaining
 * length field
 *
 * @api private
 */
function calcLengthLength(length) {
  if (length >= 0 && length < 128) {
    return 1
  } else if (length >= 128 && length < 16384) {
    return 2
  } else if (length >= 16384 && length < 2097152) {
    return 3
  } else if (length >= 2097152 && length < 268435456) {
    return 4
  } else {
    return 0
  }
}

/**
 * writeLength - write an MQTT style length field to the buffer
 *
 * @param <Buffer> buffer - destination
 * @param <Number> pos - offset
 * @param <Number> length - length (>0)
 * @returns <Number> number of bytes written
 *
 * @api private
 */

function writeLength(buffer, pos, length) {
  var digit = 0
    , origPos = pos

  do {
    digit = length % 128 | 0
    length = length / 128 | 0
    if (length > 0) {
        digit = digit | 0x80
    }
    buffer.writeUInt8(digit, pos++)
  } while (length > 0)

  return pos - origPos
}

/**
 * writeString - write a utf8 string to the buffer
 *
 * @param <Buffer> buffer - destination
 * @param <Number> pos - offset
 * @param <String> string - string to write
 * @return <Number> number of bytes written
 *
 * @api private
 */

function writeString(buffer, pos, string) {
  var strlen = Buffer.byteLength(string)
  writeNumber(buffer, pos, strlen)

  writeStringNoPos(buffer, pos + 2, string)

  return strlen + 2
}

function writeStringNoPos(buffer, pos, string) {
  buffer.write(string, pos)
}

/**
 * write_buffer - write buffer to buffer
 *
 * @param <Buffer> buffer - dest buffer
 * @param <Number> pos - offset
 * @param <Buffer> src - source buffer
 * @return <Number> number of bytes written
 *
 * @api private
 */

function writeBuffer(buffer, pos, src) {
  src.copy(buffer, pos)
  return src.length
}

/**
 * writeNumber - write a two byte number to the buffer
 *
 * @param <Buffer> buffer - destination
 * @param <Number> pos - offset
 * @param <String> number - number to write
 * @return <Number> number of bytes written
 *
 * @api private
 */
function writeNumber(buffer, pos, number) {
  buffer.writeUInt8(number >> 8, pos)
  buffer.writeUInt8(number & 0x00FF, pos + 1)

  return 2
}

/**
 * writeStringOrBuffer - write a String or Buffer with the its length prefix
 *
 * @param <Buffer> buffer - destination
 * @param <Number> pos - offset
 * @param <String> toWrite - String or Buffer
 * @return <Number> number of bytes written
 */
function writeStringOrBuffer(buffer, pos, toWrite) {
  var written = 0

  if (toWrite && typeof toWrite === 'string') {
    written += writeString(buffer, pos + written, toWrite)
  } else if (toWrite) {
    written += writeNumber(buffer, pos + written, toWrite.length)
    written += writeBuffer(buffer, pos + written, toWrite)
  } else {
    written += writeNumber(buffer, pos + written, 0)
  }

  return written
}

module.exports = generate

}).call(this,require("buffer").Buffer)
},{"./constants":11,"buffer":30}],13:[function(require,module,exports){

'use strict';

exports.parser          = require('./parser')
exports.generate        = require('./generate')

},{"./generate":12,"./parser":16}],14:[function(require,module,exports){
(function (Buffer){
var DuplexStream = require('readable-stream/duplex')
  , util         = require('util')

function BufferList (callback) {
  if (!(this instanceof BufferList))
    return new BufferList(callback)

  this._bufs  = []
  this.length = 0

  if (typeof callback == 'function') {
    this._callback = callback

    var piper = function (err) {
      if (this._callback) {
        this._callback(err)
        this._callback = null
      }
    }.bind(this)

    this.on('pipe', function (src) {
      src.on('error', piper)
    })
    this.on('unpipe', function (src) {
      src.removeListener('error', piper)
    })
  }
  else if (Buffer.isBuffer(callback))
    this.append(callback)
  else if (Array.isArray(callback)) {
    callback.forEach(function (b) {
      Buffer.isBuffer(b) && this.append(b)
    }.bind(this))
  }

  DuplexStream.call(this)
}

util.inherits(BufferList, DuplexStream)

BufferList.prototype._offset = function (offset) {
  var tot = 0, i = 0, _t
  for (; i < this._bufs.length; i++) {
    _t = tot + this._bufs[i].length
    if (offset < _t)
      return [ i, offset - tot ]
    tot = _t
  }
}

BufferList.prototype.append = function (buf) {
  var isBuffer = Buffer.isBuffer(buf) ||
                 buf instanceof BufferList

  this._bufs.push(isBuffer ? buf : new Buffer(buf))
  this.length += buf.length
  return this
}

BufferList.prototype._write = function (buf, encoding, callback) {
  this.append(buf)
  if (callback)
    callback()
}

BufferList.prototype._read = function (size) {
  if (!this.length)
    return this.push(null)
  size = Math.min(size, this.length)
  this.push(this.slice(0, size))
  this.consume(size)
}

BufferList.prototype.end = function (chunk) {
  DuplexStream.prototype.end.call(this, chunk)

  if (this._callback) {
    this._callback(null, this.slice())
    this._callback = null
  }
}

BufferList.prototype.get = function (index) {
  return this.slice(index, index + 1)[0]
}

BufferList.prototype.slice = function (start, end) {
  return this.copy(null, 0, start, end)
}

BufferList.prototype.copy = function (dst, dstStart, srcStart, srcEnd) {
  if (typeof srcStart != 'number' || srcStart < 0)
    srcStart = 0
  if (typeof srcEnd != 'number' || srcEnd > this.length)
    srcEnd = this.length
  if (srcStart >= this.length)
    return dst || new Buffer(0)
  if (srcEnd <= 0)
    return dst || new Buffer(0)

  var copy   = !!dst
    , off    = this._offset(srcStart)
    , len    = srcEnd - srcStart
    , bytes  = len
    , bufoff = (copy && dstStart) || 0
    , start  = off[1]
    , l
    , i

  // copy/slice everything
  if (srcStart === 0 && srcEnd == this.length) {
    if (!copy) // slice, just return a full concat
      return Buffer.concat(this._bufs)

    // copy, need to copy individual buffers
    for (i = 0; i < this._bufs.length; i++) {
      this._bufs[i].copy(dst, bufoff)
      bufoff += this._bufs[i].length
    }

    return dst
  }

  // easy, cheap case where it's a subset of one of the buffers
  if (bytes <= this._bufs[off[0]].length - start) {
    return copy
      ? this._bufs[off[0]].copy(dst, dstStart, start, start + bytes)
      : this._bufs[off[0]].slice(start, start + bytes)
  }

  if (!copy) // a slice, we need something to copy in to
    dst = new Buffer(len)

  for (i = off[0]; i < this._bufs.length; i++) {
    l = this._bufs[i].length - start

    if (bytes > l) {
      this._bufs[i].copy(dst, bufoff, start)
    } else {
      this._bufs[i].copy(dst, bufoff, start, start + bytes)
      break
    }

    bufoff += l
    bytes -= l

    if (start)
      start = 0
  }

  return dst
}

BufferList.prototype.toString = function (encoding, start, end) {
  return this.slice(start, end).toString(encoding)
}

BufferList.prototype.consume = function (bytes) {
  while (this._bufs.length) {
    if (bytes > this._bufs[0].length) {
      bytes -= this._bufs[0].length
      this.length -= this._bufs[0].length
      this._bufs.shift()
    } else {
      this._bufs[0] = this._bufs[0].slice(bytes)
      this.length -= bytes
      break
    }
  }
  return this
}

BufferList.prototype.duplicate = function () {
  var i = 0
    , copy = new BufferList()

  for (; i < this._bufs.length; i++)
    copy.append(this._bufs[i])

  return copy
}

BufferList.prototype.destroy = function () {
  this._bufs.length = 0;
  this.length = 0;
  this.push(null);
}

;(function () {
  var methods = {
      'readDoubleBE' : 8
    , 'readDoubleLE' : 8
    , 'readFloatBE'  : 4
    , 'readFloatLE'  : 4
    , 'readInt32BE'  : 4
    , 'readInt32LE'  : 4
    , 'readUInt32BE' : 4
    , 'readUInt32LE' : 4
    , 'readInt16BE'  : 2
    , 'readInt16LE'  : 2
    , 'readUInt16BE' : 2
    , 'readUInt16LE' : 2
    , 'readInt8'     : 1
    , 'readUInt8'    : 1
  }

  for (var m in methods) {
    (function (m) {
      BufferList.prototype[m] = function (offset) {
        return this.slice(offset, offset + methods[m])[m](0)
      }
    }(m))
  }
}())

module.exports = BufferList

}).call(this,require("buffer").Buffer)
},{"buffer":30,"readable-stream/duplex":17,"util":52}],15:[function(require,module,exports){

function Packet() {
  this.cmd = null
  this.retain = false
  this.qos = 0
  this.dup = false
  this.length = -1
  this.topic = null
  this.payload = null
}

module.exports = Packet

},{}],16:[function(require,module,exports){

var bl        = require('bl')
  , inherits  = require('inherits')
  , EE        = require('events').EventEmitter
  , Packet    = require('./packet')
  , constants = require('./constants')

function Parser() {
  if (!(this instanceof Parser)) {
    return new Parser()
  }

  this._list = bl()
  this._newPacket()

  this._states = [
      '_parseHeader'
    , '_parseLength'
    , '_parsePayload'
    , '_newPacket'
  ]
  this._stateCounter = 0
}

inherits(Parser, EE)

Parser.prototype._newPacket = function () {
  if (this.packet) {
    this._list.consume(this.packet.length)
    this.emit('packet', this.packet)
  }

  this.packet = new Packet()

  return true
}

Parser.prototype.parse = function (buf) {
  this._list.append(buf)

  while ((this.packet.length != -1 || this._list.length > 0) &&
         this[this._states[this._stateCounter]]()) {
    this._stateCounter++

    if (this._stateCounter >= this._states.length) {
      this._stateCounter = 0
    }
  }

  return this._list.length
}

Parser.prototype._parseHeader = function () {

  // there is at least one byte in the buffer
  var zero = this._list.readUInt8(0)
  this.packet.cmd = constants.types[zero >> constants.CMD_SHIFT]
  this.packet.retain = (zero & constants.RETAIN_MASK) !== 0
  this.packet.qos = (zero >> constants.QOS_SHIFT) & constants.QOS_MASK
  this.packet.dup = (zero & constants.DUP_MASK) !== 0

  this._list.consume(1)

  return true
}


Parser.prototype._parseLength = function () {
  // there is at least one byte in the list
  var bytes    = 0
    , mul      = 1
    , length   = 0
    , result   = true
    , current

  while (bytes < 5) {
    current = this._list.readUInt8(bytes++)
    length += mul * (current & constants.LENGTH_MASK)
    mul *= 0x80

    if ((current & constants.LENGTH_FIN_MASK) === 0) {
      break
    }

    if (this._list.length <= bytes) {
      result = false
      break
    }
  }

  if (result) {
    this.packet.length = length
    this._list.consume(bytes)
  }

  return result
}

Parser.prototype._parsePayload = function () {
  var result = false

  // Do we have a payload? Do we have enough data to complete the payload?
  // PINGs have no payload
  if (this.packet.length === 0 || this._list.length >= this.packet.length) {

    this._pos = 0

    switch (this.packet.cmd) {
      case 'connect':
        this._parseConnect()
        break
      case 'connack':
        this._parseConnack()
        break
      case 'publish':
        this._parsePublish()
        break
      case 'puback':
      case 'pubrec':
      case 'pubrel':
      case 'pubcomp':
        this._parseMessageId()
        break
      case 'subscribe':
        this._parseSubscribe()
        break
      case 'suback':
        this._parseSuback()
        break
      case 'unsubscribe':
        this._parseUnsubscribe()
        break
      case 'unsuback':
        this._parseUnsuback()
        break
      case 'pingreq':
      case 'pingresp':
      case 'disconnect':
        // these are empty, nothing to do
        break
      default:
        this.emit('error', new Error('not supported'))
    }

    result = true
  }

  return result
}

Parser.prototype._parseConnect = function () {
  var protocolId // constants id
    , clientId // Client id
    , topic // Will topic
    , payload // Will payload
    , password // Password
    , username // Username
    , flags = {}
    , packet = this.packet

  // Parse constants id
  protocolId = this._parseString()
  if (protocolId === null)
    return this.emit('error', new Error('cannot parse protocol id'))

  packet.protocolId = protocolId

  // Parse constants version number
  if(this._pos > this._list.length)
    return this.emit('error', new Error('packet too short'))

  packet.protocolVersion = this._list.readUInt8(this._pos)
  this._pos++

  // Parse connect flags
  flags.username  = (this._list.readUInt8(this._pos) & constants.USERNAME_MASK)
  flags.password  = (this._list.readUInt8(this._pos) & constants.PASSWORD_MASK)
  flags.will      = (this._list.readUInt8(this._pos) & constants.WILL_FLAG_MASK)

  if (flags.will) {
    packet.will         = {}
    packet.will.retain  = (this._list.readUInt8(this._pos) & constants.WILL_RETAIN_MASK) !== 0
    packet.will.qos     = (this._list.readUInt8(this._pos) &
                          constants.WILL_QOS_MASK) >> constants.WILL_QOS_SHIFT
  }

  packet.clean = (this._list.readUInt8(this._pos) & constants.CLEAN_SESSION_MASK) !== 0
  this._pos++

  // Parse keepalive
  packet.keepalive = this._parseNum()
  if(packet.keepalive === -1)
    return this.emit('error', new Error('packet too short'))

  // Parse client ID
  clientId = this._parseString()
  if(clientId === null)
    return this.emit('error', new Error('packet too short'))
  packet.clientId = clientId

  if (flags.will) {
    // Parse will topic
    topic = this._parseString()
    if (topic === null)
      return this.emit('error', new Error('cannot parse will topic'))
    packet.will.topic = topic

    // Parse will payload
    payload = this._parseBuffer()
    if (payload === null)
      return this.emit('error', new Error('cannot parse will payload'))
    packet.will.payload = payload
  }

  // Parse username
  if (flags.username) {
    username = this._parseString()
    if(username === null)
      return this.emit('error', new Error('cannot parse username'))
    packet.username = username
  }

  // Parse password
  if(flags.password) {
    password = this._parseBuffer()
    if(password === null)
      return this.emit('error', new Error('cannot parse username'))
    packet.password = password
  }

  return packet
}

Parser.prototype._parseConnack = function () {
  var packet = this.packet
  packet.sessionPresent = !!(this._list.readUInt8(this._pos++) & constants.SESSIONPRESENT_MASK)
  packet.returnCode = this._list.readUInt8(this._pos)
  if(packet.returnCode === -1)
    return this.emit('error', new Error('cannot parse return code'))
}

Parser.prototype._parsePublish = function () {
  var packet = this.packet
  packet.topic = this._parseString()

  if(packet.topic === null)
    return this.emit('error', new Error('cannot parse topic'))

  // Parse message ID
  if (packet.qos > 0) {
    if (!this._parseMessageId()) { return }
  }

  packet.payload = this._list.slice(this._pos, packet.length)
}

Parser.prototype._parseSubscribe = function() {
  var packet = this.packet
    , topic
    , qos

  if (packet.qos != 1) {
    return this.emit('error', new Error('wrong subscribe header'))
  }

  packet.subscriptions = []

  if (!this._parseMessageId()) { return }

  while (this._pos < packet.length) {

    // Parse topic
    topic = this._parseString()
    if (topic === null)
      return this.emit('error', new Error('Parse error - cannot parse topic'))

    qos = this._list.readUInt8(this._pos++)

    // Push pair to subscriptions
    packet.subscriptions.push({ topic: topic, qos: qos });
  }
}

Parser.prototype._parseSuback = function() {
  this.packet.granted = []

  if (!this._parseMessageId()) { return }

  // Parse granted QoSes
  while (this._pos < this.packet.length) {
    this.packet.granted.push(this._list.readUInt8(this._pos++));
  }
}

Parser.prototype._parseUnsubscribe = function() {
  var packet = this.packet

  packet.unsubscriptions = []

  // Parse message ID
  if (!this._parseMessageId()) { return }

  while (this._pos < packet.length) {
    var topic;

    // Parse topic
    topic = this._parseString()
    if (topic === null)
      return this.emit('error', new Error('cannot parse topic'))

    // Push topic to unsubscriptions
    packet.unsubscriptions.push(topic);
  }
}

Parser.prototype._parseUnsuback = function() {
  if (!this._parseMessageId())
    return this.emit('error', new Error('cannot parse message id'))
}

Parser.prototype._parseMessageId = function() {
  var packet = this.packet

  packet.messageId = this._parseNum()

  if(packet.messageId === null) {
    this.emit('error', new Error('cannot parse message id'))
    return false
  }

  return true
}

Parser.prototype._parseString = function(maybeBuffer) {
  var length = this._parseNum()
    , result

  if(length === -1 || length + this._pos > this._list.length)
    return null

  result = this._list.toString('utf8', this._pos, this._pos + length)

  this._pos += length

  return result
}

Parser.prototype._parseBuffer = function() {
  var length = this._parseNum()
    , result

  if(length === -1 || length + this._pos > this._list.length)
    return null

  result = this._list.slice(this._pos, this._pos + length)

  this._pos += length

  return result
}

Parser.prototype._parseNum = function() {
  if(2 > this._pos + this._list.length) return -1

  var result = this._list.readUInt16BE(this._pos)
  this._pos += 2
  return result
}

module.exports = Parser

},{"./constants":11,"./packet":15,"bl":14,"events":34,"inherits":10}],17:[function(require,module,exports){
module.exports = require("./lib/_stream_duplex.js")

},{"./lib/_stream_duplex.js":18}],18:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// a duplex stream is just a stream that is both readable and writable.
// Since JS doesn't have multiple prototypal inheritance, this class
// prototypally inherits from Readable, and then parasitically from
// Writable.

module.exports = Duplex;

/*<replacement>*/
var objectKeys = Object.keys || function (obj) {
  var keys = [];
  for (var key in obj) keys.push(key);
  return keys;
}
/*</replacement>*/


/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Readable = require('./_stream_readable');
var Writable = require('./_stream_writable');

util.inherits(Duplex, Readable);

forEach(objectKeys(Writable.prototype), function(method) {
  if (!Duplex.prototype[method])
    Duplex.prototype[method] = Writable.prototype[method];
});

function Duplex(options) {
  if (!(this instanceof Duplex))
    return new Duplex(options);

  Readable.call(this, options);
  Writable.call(this, options);

  if (options && options.readable === false)
    this.readable = false;

  if (options && options.writable === false)
    this.writable = false;

  this.allowHalfOpen = true;
  if (options && options.allowHalfOpen === false)
    this.allowHalfOpen = false;

  this.once('end', onend);
}

// the no-half-open enforcer
function onend() {
  // if we allow half-open state, or if the writable side ended,
  // then we're ok.
  if (this.allowHalfOpen || this._writableState.ended)
    return;

  // no more data can be written.
  // But allow more writes to happen in this tick.
  process.nextTick(this.end.bind(this));
}

function forEach (xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

}).call(this,require('_process'))
},{"./_stream_readable":20,"./_stream_writable":22,"_process":37,"core-util-is":23,"inherits":10}],19:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// a passthrough stream.
// basically just the most minimal sort of Transform stream.
// Every written chunk gets output as-is.

module.exports = PassThrough;

var Transform = require('./_stream_transform');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(PassThrough, Transform);

function PassThrough(options) {
  if (!(this instanceof PassThrough))
    return new PassThrough(options);

  Transform.call(this, options);
}

PassThrough.prototype._transform = function(chunk, encoding, cb) {
  cb(null, chunk);
};

},{"./_stream_transform":21,"core-util-is":23,"inherits":10}],20:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

module.exports = Readable;

/*<replacement>*/
var isArray = require('isarray');
/*</replacement>*/


/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Readable.ReadableState = ReadableState;

var EE = require('events').EventEmitter;

/*<replacement>*/
if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

var Stream = require('stream');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var StringDecoder;

util.inherits(Readable, Stream);

function ReadableState(options, stream) {
  options = options || {};

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : 16 * 1024;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.buffer = [];
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = false;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // In streams that never have any data, and do push(null) right away,
  // the consumer can miss the 'end' event if they do some I/O before
  // consuming the stream.  So, we don't emit('end') until some reading
  // happens.
  this.calledRead = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, becuase any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;


  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    if (!StringDecoder)
      StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

function Readable(options) {
  if (!(this instanceof Readable))
    return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  Stream.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function(chunk, encoding) {
  var state = this._readableState;

  if (typeof chunk === 'string' && !state.objectMode) {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = new Buffer(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function(chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (chunk === null || chunk === undefined) {
    state.reading = false;
    if (!state.ended)
      onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var e = new Error('stream.unshift() after end event');
      stream.emit('error', e);
    } else {
      if (state.decoder && !addToFront && !encoding)
        chunk = state.decoder.write(chunk);

      // update the buffer info.
      state.length += state.objectMode ? 1 : chunk.length;
      if (addToFront) {
        state.buffer.unshift(chunk);
      } else {
        state.reading = false;
        state.buffer.push(chunk);
      }

      if (state.needReadable)
        emitReadable(stream);

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}



// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended &&
         (state.needReadable ||
          state.length < state.highWaterMark ||
          state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function(enc) {
  if (!StringDecoder)
    StringDecoder = require('string_decoder/').StringDecoder;
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
};

// Don't raise the hwm > 128MB
var MAX_HWM = 0x800000;
function roundUpToNextPowerOf2(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2
    n--;
    for (var p = 1; p < 32; p <<= 1) n |= n >> p;
    n++;
  }
  return n;
}

function howMuchToRead(n, state) {
  if (state.length === 0 && state.ended)
    return 0;

  if (state.objectMode)
    return n === 0 ? 0 : 1;

  if (n === null || isNaN(n)) {
    // only flow one buffer at a time
    if (state.flowing && state.buffer.length)
      return state.buffer[0].length;
    else
      return state.length;
  }

  if (n <= 0)
    return 0;

  // If we're asking for more than the target buffer level,
  // then raise the water mark.  Bump up to the next highest
  // power of 2, to prevent increasing it excessively in tiny
  // amounts.
  if (n > state.highWaterMark)
    state.highWaterMark = roundUpToNextPowerOf2(n);

  // don't have that much.  return null, unless we've ended.
  if (n > state.length) {
    if (!state.ended) {
      state.needReadable = true;
      return 0;
    } else
      return state.length;
  }

  return n;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function(n) {
  var state = this._readableState;
  state.calledRead = true;
  var nOrig = n;
  var ret;

  if (typeof n !== 'number' || n > 0)
    state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 &&
      state.needReadable &&
      (state.length >= state.highWaterMark || state.ended)) {
    emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    ret = null;

    // In cases where the decoder did not receive enough data
    // to produce a full chunk, then immediately received an
    // EOF, state.buffer will contain [<Buffer >, <Buffer 00 ...>].
    // howMuchToRead will see this and coerce the amount to
    // read to zero (because it's looking at the length of the
    // first <Buffer > in state.buffer), and we'll end up here.
    //
    // This can only happen via state.decoder -- no other venue
    // exists for pushing a zero-length chunk into state.buffer
    // and triggering this behavior. In this case, we return our
    // remaining data and end the stream, if appropriate.
    if (state.length > 0 && state.decoder) {
      ret = fromList(n, state);
      state.length -= ret.length;
    }

    if (state.length === 0)
      endReadable(this);

    return ret;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;

  // if we currently have less than the highWaterMark, then also read some
  if (state.length - n <= state.highWaterMark)
    doRead = true;

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading)
    doRead = false;

  if (doRead) {
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0)
      state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
  }

  // If _read called its callback synchronously, then `reading`
  // will be false, and we need to re-evaluate how much data we
  // can return to the user.
  if (doRead && !state.reading)
    n = howMuchToRead(nOrig, state);

  if (n > 0)
    ret = fromList(n, state);
  else
    ret = null;

  if (ret === null) {
    state.needReadable = true;
    n = 0;
  }

  state.length -= n;

  // If we have nothing in the buffer, then we want to know
  // as soon as we *do* get something into the buffer.
  if (state.length === 0 && !state.ended)
    state.needReadable = true;

  // If we happened to read() exactly the remaining amount in the
  // buffer, and the EOF has been seen at this point, then make sure
  // that we emit 'end' on the very next tick.
  if (state.ended && !state.endEmitted && state.length === 0)
    endReadable(this);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!Buffer.isBuffer(chunk) &&
      'string' !== typeof chunk &&
      chunk !== null &&
      chunk !== undefined &&
      !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}


function onEofChunk(stream, state) {
  if (state.decoder && !state.ended) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // if we've ended and we have some data left, then emit
  // 'readable' now to make sure it gets picked up.
  if (state.length > 0)
    emitReadable(stream);
  else
    endReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (state.emittedReadable)
    return;

  state.emittedReadable = true;
  if (state.sync)
    process.nextTick(function() {
      emitReadable_(stream);
    });
  else
    emitReadable_(stream);
}

function emitReadable_(stream) {
  stream.emit('readable');
}


// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    process.nextTick(function() {
      maybeReadMore_(stream, state);
    });
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended &&
         state.length < state.highWaterMark) {
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;
    else
      len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function(n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function(dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;

  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
              dest !== process.stdout &&
              dest !== process.stderr;

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted)
    process.nextTick(endFn);
  else
    src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    if (readable !== src) return;
    cleanup();
  }

  function onend() {
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  function cleanup() {
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (!dest._writableState || dest._writableState.needDrain)
      ondrain();
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    unpipe();
    dest.removeListener('error', onerror);
    if (EE.listenerCount(dest, 'error') === 0)
      dest.emit('error', er);
  }
  // This is a brutally ugly hack to make sure that our error handler
  // is attached before any userland ones.  NEVER DO THIS.
  if (!dest._events || !dest._events.error)
    dest.on('error', onerror);
  else if (isArray(dest._events.error))
    dest._events.error.unshift(onerror);
  else
    dest._events.error = [onerror, dest._events.error];



  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    // the handler that waits for readable events after all
    // the data gets sucked out in flow.
    // This would be easier to follow with a .once() handler
    // in flow(), but that is too slow.
    this.on('readable', pipeOnReadable);

    state.flowing = true;
    process.nextTick(function() {
      flow(src);
    });
  }

  return dest;
};

function pipeOnDrain(src) {
  return function() {
    var dest = this;
    var state = src._readableState;
    state.awaitDrain--;
    if (state.awaitDrain === 0)
      flow(src);
  };
}

function flow(src) {
  var state = src._readableState;
  var chunk;
  state.awaitDrain = 0;

  function write(dest, i, list) {
    var written = dest.write(chunk);
    if (false === written) {
      state.awaitDrain++;
    }
  }

  while (state.pipesCount && null !== (chunk = src.read())) {

    if (state.pipesCount === 1)
      write(state.pipes, 0, null);
    else
      forEach(state.pipes, write);

    src.emit('data', chunk);

    // if anyone needs a drain, then we have to wait for that.
    if (state.awaitDrain > 0)
      return;
  }

  // if every destination was unpiped, either before entering this
  // function, or in the while loop, then stop flowing.
  //
  // NB: This is a pretty rare edge case.
  if (state.pipesCount === 0) {
    state.flowing = false;

    // if there were data event listeners added, then switch to old mode.
    if (EE.listenerCount(src, 'data') > 0)
      emitDataEvents(src);
    return;
  }

  // at this point, no one needed a drain, so we just ran out of data
  // on the next readable event, start it over again.
  state.ranOut = true;
}

function pipeOnReadable() {
  if (this._readableState.ranOut) {
    this._readableState.ranOut = false;
    flow(this);
  }
}


Readable.prototype.unpipe = function(dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0)
    return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes)
      return this;

    if (!dest)
      dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    this.removeListener('readable', pipeOnReadable);
    state.flowing = false;
    if (dest)
      dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    this.removeListener('readable', pipeOnReadable);
    state.flowing = false;

    for (var i = 0; i < len; i++)
      dests[i].emit('unpipe', this);
    return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1)
    return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1)
    state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function(ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);

  if (ev === 'data' && !this._readableState.flowing)
    emitDataEvents(this);

  if (ev === 'readable' && this.readable) {
    var state = this._readableState;
    if (!state.readableListening) {
      state.readableListening = true;
      state.emittedReadable = false;
      state.needReadable = true;
      if (!state.reading) {
        this.read(0);
      } else if (state.length) {
        emitReadable(this, state);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function() {
  emitDataEvents(this);
  this.read(0);
  this.emit('resume');
};

Readable.prototype.pause = function() {
  emitDataEvents(this, true);
  this.emit('pause');
};

function emitDataEvents(stream, startPaused) {
  var state = stream._readableState;

  if (state.flowing) {
    // https://github.com/isaacs/readable-stream/issues/16
    throw new Error('Cannot switch to old mode now.');
  }

  var paused = startPaused || false;
  var readable = false;

  // convert to an old-style stream.
  stream.readable = true;
  stream.pipe = Stream.prototype.pipe;
  stream.on = stream.addListener = Stream.prototype.on;

  stream.on('readable', function() {
    readable = true;

    var c;
    while (!paused && (null !== (c = stream.read())))
      stream.emit('data', c);

    if (c === null) {
      readable = false;
      stream._readableState.needReadable = true;
    }
  });

  stream.pause = function() {
    paused = true;
    this.emit('pause');
  };

  stream.resume = function() {
    paused = false;
    if (readable)
      process.nextTick(function() {
        stream.emit('readable');
      });
    else
      this.read(0);
    this.emit('resume');
  };

  // now make it start, just in case it hadn't already.
  stream.emit('readable');
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function(stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function() {
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length)
        self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function(chunk) {
    if (state.decoder)
      chunk = state.decoder.write(chunk);

    // don't skip over falsy values in objectMode
    //if (state.objectMode && util.isNullOrUndefined(chunk))
    if (state.objectMode && (chunk === null || chunk === undefined))
      return;
    else if (!state.objectMode && (!chunk || !chunk.length))
      return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (typeof stream[i] === 'function' &&
        typeof this[i] === 'undefined') {
      this[i] = function(method) { return function() {
        return stream[method].apply(stream, arguments);
      }}(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function(ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function(n) {
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};



// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
function fromList(n, state) {
  var list = state.buffer;
  var length = state.length;
  var stringMode = !!state.decoder;
  var objectMode = !!state.objectMode;
  var ret;

  // nothing in the list, definitely empty.
  if (list.length === 0)
    return null;

  if (length === 0)
    ret = null;
  else if (objectMode)
    ret = list.shift();
  else if (!n || n >= length) {
    // read it all, truncate the array.
    if (stringMode)
      ret = list.join('');
    else
      ret = Buffer.concat(list, length);
    list.length = 0;
  } else {
    // read just some of it.
    if (n < list[0].length) {
      // just take a part of the first list item.
      // slice is the same for buffers and strings.
      var buf = list[0];
      ret = buf.slice(0, n);
      list[0] = buf.slice(n);
    } else if (n === list[0].length) {
      // first list is a perfect match
      ret = list.shift();
    } else {
      // complex case.
      // we have enough to cover it, but it spans past the first buffer.
      if (stringMode)
        ret = '';
      else
        ret = new Buffer(n);

      var c = 0;
      for (var i = 0, l = list.length; i < l && c < n; i++) {
        var buf = list[0];
        var cpy = Math.min(n - c, buf.length);

        if (stringMode)
          ret += buf.slice(0, cpy);
        else
          buf.copy(ret, c, 0, cpy);

        if (cpy < buf.length)
          list[0] = buf.slice(cpy);
        else
          list.shift();

        c += cpy;
      }
    }
  }

  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0)
    throw new Error('endReadable called on non-empty stream');

  if (!state.endEmitted && state.calledRead) {
    state.ended = true;
    process.nextTick(function() {
      // Check that we didn't get one last unshift.
      if (!state.endEmitted && state.length === 0) {
        state.endEmitted = true;
        stream.readable = false;
        stream.emit('end');
      }
    });
  }
}

function forEach (xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf (xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}

}).call(this,require('_process'))
},{"_process":37,"buffer":30,"core-util-is":23,"events":34,"inherits":10,"isarray":24,"stream":49,"string_decoder/":25}],21:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.


// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.

module.exports = Transform;

var Duplex = require('./_stream_duplex');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(Transform, Duplex);


function TransformState(options, stream) {
  this.afterTransform = function(er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb)
    return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (data !== null && data !== undefined)
    stream.push(data);

  if (cb)
    cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}


function Transform(options) {
  if (!(this instanceof Transform))
    return new Transform(options);

  Duplex.call(this, options);

  var ts = this._transformState = new TransformState(options, this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  this.once('finish', function() {
    if ('function' === typeof this._flush)
      this._flush(function(er) {
        done(stream, er);
      });
    else
      done(stream);
  });
}

Transform.prototype.push = function(chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function(chunk, encoding, cb) {
  throw new Error('not implemented');
};

Transform.prototype._write = function(chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform ||
        rs.needReadable ||
        rs.length < rs.highWaterMark)
      this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function(n) {
  var ts = this._transformState;

  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};


function done(stream, er) {
  if (er)
    return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var rs = stream._readableState;
  var ts = stream._transformState;

  if (ws.length)
    throw new Error('calling transform done when ws.length != 0');

  if (ts.transforming)
    throw new Error('calling transform done when still transforming');

  return stream.push(null);
}

},{"./_stream_duplex":18,"core-util-is":23,"inherits":10}],22:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// A bit simpler than readable streams.
// Implement an async ._write(chunk, cb), and it'll handle all
// the drain event emission and buffering.

module.exports = Writable;

/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Writable.WritableState = WritableState;


/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Stream = require('stream');

util.inherits(Writable, Stream);

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
}

function WritableState(options, stream) {
  options = options || {};

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : 16 * 1024;

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, becuase any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function(er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.buffer = [];

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;
}

function Writable(options) {
  var Duplex = require('./_stream_duplex');

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex))
    return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  Stream.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function() {
  this.emit('error', new Error('Cannot pipe. Not readable.'));
};


function writeAfterEnd(stream, state, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  process.nextTick(function() {
    cb(er);
  });
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;
  if (!Buffer.isBuffer(chunk) &&
      'string' !== typeof chunk &&
      chunk !== null &&
      chunk !== undefined &&
      !state.objectMode) {
    var er = new TypeError('Invalid non-string/buffer chunk');
    stream.emit('error', er);
    process.nextTick(function() {
      cb(er);
    });
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function(chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (Buffer.isBuffer(chunk))
    encoding = 'buffer';
  else if (!encoding)
    encoding = state.defaultEncoding;

  if (typeof cb !== 'function')
    cb = function() {};

  if (state.ended)
    writeAfterEnd(this, state, cb);
  else if (validChunk(this, state, chunk, cb))
    ret = writeOrBuffer(this, state, chunk, encoding, cb);

  return ret;
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode &&
      state.decodeStrings !== false &&
      typeof chunk === 'string') {
    chunk = new Buffer(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);
  if (Buffer.isBuffer(chunk))
    encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret)
    state.needDrain = true;

  if (state.writing)
    state.buffer.push(new WriteReq(chunk, encoding, cb));
  else
    doWrite(stream, state, len, chunk, encoding, cb);

  return ret;
}

function doWrite(stream, state, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  if (sync)
    process.nextTick(function() {
      cb(er);
    });
  else
    cb(er);

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er)
    onwriteError(stream, state, sync, er, cb);
  else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(stream, state);

    if (!finished && !state.bufferProcessing && state.buffer.length)
      clearBuffer(stream, state);

    if (sync) {
      process.nextTick(function() {
        afterWrite(stream, state, finished, cb);
      });
    } else {
      afterWrite(stream, state, finished, cb);
    }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished)
    onwriteDrain(stream, state);
  cb();
  if (finished)
    finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}


// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;

  for (var c = 0; c < state.buffer.length; c++) {
    var entry = state.buffer[c];
    var chunk = entry.chunk;
    var encoding = entry.encoding;
    var cb = entry.callback;
    var len = state.objectMode ? 1 : chunk.length;

    doWrite(stream, state, len, chunk, encoding, cb);

    // if we didn't call the onwrite immediately, then
    // it means that we need to wait until it does.
    // also, that means that the chunk and cb are currently
    // being processed, so move the buffer counter past them.
    if (state.writing) {
      c++;
      break;
    }
  }

  state.bufferProcessing = false;
  if (c < state.buffer.length)
    state.buffer = state.buffer.slice(c);
  else
    state.buffer.length = 0;
}

Writable.prototype._write = function(chunk, encoding, cb) {
  cb(new Error('not implemented'));
};

Writable.prototype.end = function(chunk, encoding, cb) {
  var state = this._writableState;

  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (typeof chunk !== 'undefined' && chunk !== null)
    this.write(chunk, encoding);

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished)
    endWritable(this, state, cb);
};


function needFinish(stream, state) {
  return (state.ending &&
          state.length === 0 &&
          !state.finished &&
          !state.writing);
}

function finishMaybe(stream, state) {
  var need = needFinish(stream, state);
  if (need) {
    state.finished = true;
    stream.emit('finish');
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished)
      process.nextTick(cb);
    else
      stream.once('finish', cb);
  }
  state.ended = true;
}

}).call(this,require('_process'))
},{"./_stream_duplex":18,"_process":37,"buffer":30,"core-util-is":23,"inherits":10,"stream":49}],23:[function(require,module,exports){
(function (Buffer){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
  return Array.isArray(ar);
}
exports.isArray = isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return isObject(re) && objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
  return isObject(d) && objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
  return isObject(e) &&
      (objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

function isBuffer(arg) {
  return Buffer.isBuffer(arg);
}
exports.isBuffer = isBuffer;

function objectToString(o) {
  return Object.prototype.toString.call(o);
}
}).call(this,require("buffer").Buffer)
},{"buffer":30}],24:[function(require,module,exports){
module.exports = Array.isArray || function (arr) {
  return Object.prototype.toString.call(arr) == '[object Array]';
};

},{}],25:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

var Buffer = require('buffer').Buffer;

var isBufferEncoding = Buffer.isEncoding
  || function(encoding) {
       switch (encoding && encoding.toLowerCase()) {
         case 'hex': case 'utf8': case 'utf-8': case 'ascii': case 'binary': case 'base64': case 'ucs2': case 'ucs-2': case 'utf16le': case 'utf-16le': case 'raw': return true;
         default: return false;
       }
     }


function assertEncoding(encoding) {
  if (encoding && !isBufferEncoding(encoding)) {
    throw new Error('Unknown encoding: ' + encoding);
  }
}

// StringDecoder provides an interface for efficiently splitting a series of
// buffers into a series of JS strings without breaking apart multi-byte
// characters. CESU-8 is handled as part of the UTF-8 encoding.
//
// @TODO Handling all encodings inside a single object makes it very difficult
// to reason about this code, so it should be split up in the future.
// @TODO There should be a utf8-strict encoding that rejects invalid UTF-8 code
// points as used by CESU-8.
var StringDecoder = exports.StringDecoder = function(encoding) {
  this.encoding = (encoding || 'utf8').toLowerCase().replace(/[-_]/, '');
  assertEncoding(encoding);
  switch (this.encoding) {
    case 'utf8':
      // CESU-8 represents each of Surrogate Pair by 3-bytes
      this.surrogateSize = 3;
      break;
    case 'ucs2':
    case 'utf16le':
      // UTF-16 represents each of Surrogate Pair by 2-bytes
      this.surrogateSize = 2;
      this.detectIncompleteChar = utf16DetectIncompleteChar;
      break;
    case 'base64':
      // Base-64 stores 3 bytes in 4 chars, and pads the remainder.
      this.surrogateSize = 3;
      this.detectIncompleteChar = base64DetectIncompleteChar;
      break;
    default:
      this.write = passThroughWrite;
      return;
  }

  // Enough space to store all bytes of a single character. UTF-8 needs 4
  // bytes, but CESU-8 may require up to 6 (3 bytes per surrogate).
  this.charBuffer = new Buffer(6);
  // Number of bytes received for the current incomplete multi-byte character.
  this.charReceived = 0;
  // Number of bytes expected for the current incomplete multi-byte character.
  this.charLength = 0;
};


// write decodes the given buffer and returns it as JS string that is
// guaranteed to not contain any partial multi-byte characters. Any partial
// character found at the end of the buffer is buffered up, and will be
// returned when calling write again with the remaining bytes.
//
// Note: Converting a Buffer containing an orphan surrogate to a String
// currently works, but converting a String to a Buffer (via `new Buffer`, or
// Buffer#write) will replace incomplete surrogates with the unicode
// replacement character. See https://codereview.chromium.org/121173009/ .
StringDecoder.prototype.write = function(buffer) {
  var charStr = '';
  // if our last write ended with an incomplete multibyte character
  while (this.charLength) {
    // determine how many remaining bytes this buffer has to offer for this char
    var available = (buffer.length >= this.charLength - this.charReceived) ?
        this.charLength - this.charReceived :
        buffer.length;

    // add the new bytes to the char buffer
    buffer.copy(this.charBuffer, this.charReceived, 0, available);
    this.charReceived += available;

    if (this.charReceived < this.charLength) {
      // still not enough chars in this buffer? wait for more ...
      return '';
    }

    // remove bytes belonging to the current character from the buffer
    buffer = buffer.slice(available, buffer.length);

    // get the character that was split
    charStr = this.charBuffer.slice(0, this.charLength).toString(this.encoding);

    // CESU-8: lead surrogate (D800-DBFF) is also the incomplete character
    var charCode = charStr.charCodeAt(charStr.length - 1);
    if (charCode >= 0xD800 && charCode <= 0xDBFF) {
      this.charLength += this.surrogateSize;
      charStr = '';
      continue;
    }
    this.charReceived = this.charLength = 0;

    // if there are no more bytes in this buffer, just emit our char
    if (buffer.length === 0) {
      return charStr;
    }
    break;
  }

  // determine and set charLength / charReceived
  this.detectIncompleteChar(buffer);

  var end = buffer.length;
  if (this.charLength) {
    // buffer the incomplete character bytes we got
    buffer.copy(this.charBuffer, 0, buffer.length - this.charReceived, end);
    end -= this.charReceived;
  }

  charStr += buffer.toString(this.encoding, 0, end);

  var end = charStr.length - 1;
  var charCode = charStr.charCodeAt(end);
  // CESU-8: lead surrogate (D800-DBFF) is also the incomplete character
  if (charCode >= 0xD800 && charCode <= 0xDBFF) {
    var size = this.surrogateSize;
    this.charLength += size;
    this.charReceived += size;
    this.charBuffer.copy(this.charBuffer, size, 0, size);
    buffer.copy(this.charBuffer, 0, 0, size);
    return charStr.substring(0, end);
  }

  // or just emit the charStr
  return charStr;
};

// detectIncompleteChar determines if there is an incomplete UTF-8 character at
// the end of the given buffer. If so, it sets this.charLength to the byte
// length that character, and sets this.charReceived to the number of bytes
// that are available for this character.
StringDecoder.prototype.detectIncompleteChar = function(buffer) {
  // determine how many bytes we have to check at the end of this buffer
  var i = (buffer.length >= 3) ? 3 : buffer.length;

  // Figure out if one of the last i bytes of our buffer announces an
  // incomplete char.
  for (; i > 0; i--) {
    var c = buffer[buffer.length - i];

    // See http://en.wikipedia.org/wiki/UTF-8#Description

    // 110XXXXX
    if (i == 1 && c >> 5 == 0x06) {
      this.charLength = 2;
      break;
    }

    // 1110XXXX
    if (i <= 2 && c >> 4 == 0x0E) {
      this.charLength = 3;
      break;
    }

    // 11110XXX
    if (i <= 3 && c >> 3 == 0x1E) {
      this.charLength = 4;
      break;
    }
  }
  this.charReceived = i;
};

StringDecoder.prototype.end = function(buffer) {
  var res = '';
  if (buffer && buffer.length)
    res = this.write(buffer);

  if (this.charReceived) {
    var cr = this.charReceived;
    var buf = this.charBuffer;
    var enc = this.encoding;
    res += buf.slice(0, cr).toString(enc);
  }

  return res;
};

function passThroughWrite(buffer) {
  return buffer.toString(this.encoding);
}

function utf16DetectIncompleteChar(buffer) {
  this.charReceived = buffer.length % 2;
  this.charLength = this.charReceived ? 2 : 0;
}

function base64DetectIncompleteChar(buffer) {
  this.charReceived = buffer.length % 3;
  this.charLength = this.charReceived ? 3 : 0;
}

},{"buffer":30}],26:[function(require,module,exports){
var Stream = require('stream'); // hack to fix a circular dependency issue when used with browserify
exports = module.exports = require('./lib/_stream_readable.js');
exports.Stream = Stream;
exports.Readable = exports;
exports.Writable = require('./lib/_stream_writable.js');
exports.Duplex = require('./lib/_stream_duplex.js');
exports.Transform = require('./lib/_stream_transform.js');
exports.PassThrough = require('./lib/_stream_passthrough.js');

},{"./lib/_stream_duplex.js":18,"./lib/_stream_passthrough.js":19,"./lib/_stream_readable.js":20,"./lib/_stream_transform.js":21,"./lib/_stream_writable.js":22,"stream":49}],27:[function(require,module,exports){
module.exports = Adapter;

var MqttClient = require('mqtt/lib/client');
var EventEmitter = require('events').EventEmitter;
var inherits = require('util').inherits;
var debug = require('debug')('strong-pubsub:mqtt');
var defaults = require('lodash').defaults;

function noop() {};

/**
 * The **MQTT** `Adapter`.
 *
 * **Defaults**
 *
 * - `client.options.mqtt` - The adapter sets these defaults
 * - `client.options.mqtt.protocolId` - `'MQIsdp'`
 * - `client.options.mqtt.protocolVersion` - `3`
 *
 * @class
 */

function Adapter(client) {
  var adapter = this;
  this.client = client;
  var options = this.options = client.options;
  options.mqtt = options.mqtt || {};

  defaults(options.mqtt, {
    protocolId: 'MQIsdp',
    protocolVersion: 3
  });
  
  this.transport = client.transport;
}

inherits(Adapter, EventEmitter);

Adapter.prototype.connect = function(cb) {
  var adapter = this;
  var client = this.client;
  var options = this.options;
  var transport = this.transport || require('net');
  var firstConnection;
  var timer;

  debug('connect');

  this.mqttClient = new MqttClient(function(mqttClient) {
    debug('mqtt client creating new connection');
    var connection = transport.createConnection(options.port, options.host, options);
    if(!firstConnection) {
      firstConnection = connection
    }
    return connection;
  }, options.mqtt);

  this.mqttClient.on('message', function(topic, message, packet) {
    client.emit('message', topic, message, {
      qos: packet.qos || 0,
      retain: packet.retain || false
    });
  });

  firstConnection.once('connect', done);
  firstConnection.once('error', done);

  if(options.connectionTimeout) {
    timer = setTimeout(function() {
      cb(new Error('connection timeout after ' + options.connectionTimeout + 'ms'));
      firstConnection.close();
    }, options.connectionTimeout);
  }

  function done(err) {
    debug('connect done');
    if(err) {
      debug('connect error %j', err);
    }
    adapter.emit('connect');
    clearTimeout(timer);
    cb(err);
  }
}

Adapter.prototype.end = function(cb) {
  this.mqttClient.end(cb);
}

/**
 * Publish a `message` to the specified `topic`.
 *
 * @param {String} topic The topic to publish to.
 * @param {String|Buffer} message The message to publish to the topic.
 * @param {Object} [options] Additional options that are not required for publishing a message.
 * @param {Number} [options.qos] **default: `0`** The **MQTT** QoS (Quality of Service) setting.
 * @param {Boolean} [options.retain] **default: `false`**  The `MQTT` retain setting. Whether or not the message should be retained.
 *
 * **Supported Values**
 *
 *   - `0` - Just as reliable as TCP. Adapter will not get any missed messages (while it was disconnected).
 *   - `1` - Adapter receives missed messages at least once and sometimes more than once.
 *   - `2` - Adapter receives missed messages only once.
 *
 * @callback {Function} callback Called once the adapter has successfully finished publishing the message.
 * @param {Error} err An error object is included if an error was supplied by the adapter.
 */

Adapter.prototype.publish = function(topic, message, options, cb) {
  options = options || {};
  options.qos = options.qos || 0;
  options.retain = options.retain || false;
  this.mqttClient.publish(topic, message, options, cb);
}

/**
 * Subscribe to the specified `topic` or **topic pattern**.
 *
 * @param {String} topic The topic to subscribe to.
 * @param {Object} options The MQTT specific options.
 * @param {Object} options.qos See `publish()` for `options.qos`.
 *
 * @callback {Function} callback Called once the adapter has finished subscribing.
 * @param {Error} err An error object is included if an error was supplied by the adapter.
 * @param {Object[]} granted An array of topics granted formatted as an object `{topic: 't', qos: n}`. 
 * @param {String} granted[n].topic The topic granted 
 * @param {String} granted[n].qos The qos for the topic 
 */

Adapter.prototype.subscribe = function(topic, options, cb) {
  cb = cb || noop;
  options.qos = options.qos || 0;

  if(typeof topic === 'object') {
    Object.keys(topic).forEach(function(name) {
      topic[name] = topic[name].qos || 0;
    });
  }

  this.mqttClient.subscribe(topic, options, cb);
}

/**
 * Unsubscribe from the specified `topic` or **topic pattern**.
 *
 * @param {String} topic The topic or **topic pattern** to unsubscribe.
 * @callback {Function} callback Called once the adapter has finished unsubscribing.
 * @param {Error} err An error object is included if an error was supplied by the adapter.
 */

Adapter.prototype.unsubscribe = function(topic, cb) {
  cb = cb || noop;
  this.mqttClient.unsubscribe(topic, cb);
}

},{"debug":1,"events":34,"lodash":4,"mqtt/lib/client":5,"net":28,"util":52}],28:[function(require,module,exports){

},{}],29:[function(require,module,exports){
arguments[4][28][0].apply(exports,arguments)
},{"dup":28}],30:[function(require,module,exports){
/*!
 * The buffer module from node.js, for the browser.
 *
 * @author   Feross Aboukhadijeh <feross@feross.org> <http://feross.org>
 * @license  MIT
 */

var base64 = require('base64-js')
var ieee754 = require('ieee754')
var isArray = require('is-array')

exports.Buffer = Buffer
exports.SlowBuffer = SlowBuffer
exports.INSPECT_MAX_BYTES = 50
Buffer.poolSize = 8192 // not used by this implementation

var kMaxLength = 0x3fffffff
var rootParent = {}

/**
 * If `Buffer.TYPED_ARRAY_SUPPORT`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Use Object implementation (most compatible, even IE6)
 *
 * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
 * Opera 11.6+, iOS 4.2+.
 *
 * Note:
 *
 * - Implementation must support adding new properties to `Uint8Array` instances.
 *   Firefox 4-29 lacked support, fixed in Firefox 30+.
 *   See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438.
 *
 *  - Chrome 9-10 is missing the `TypedArray.prototype.subarray` function.
 *
 *  - IE10 has a broken `TypedArray.prototype.subarray` function which returns arrays of
 *    incorrect length in some situations.
 *
 * We detect these buggy browsers and set `Buffer.TYPED_ARRAY_SUPPORT` to `false` so they will
 * get the Object implementation, which is slower but will work correctly.
 */
Buffer.TYPED_ARRAY_SUPPORT = (function () {
  try {
    var buf = new ArrayBuffer(0)
    var arr = new Uint8Array(buf)
    arr.foo = function () { return 42 }
    return arr.foo() === 42 && // typed array instances can be augmented
        typeof arr.subarray === 'function' && // chrome 9-10 lack `subarray`
        new Uint8Array(1).subarray(1, 1).byteLength === 0 // ie10 has broken `subarray`
  } catch (e) {
    return false
  }
})()

/**
 * Class: Buffer
 * =============
 *
 * The Buffer constructor returns instances of `Uint8Array` that are augmented
 * with function properties for all the node `Buffer` API functions. We use
 * `Uint8Array` so that square bracket notation works as expected -- it returns
 * a single octet.
 *
 * By augmenting the instances, we can avoid modifying the `Uint8Array`
 * prototype.
 */
function Buffer (subject, encoding) {
  var self = this
  if (!(self instanceof Buffer)) return new Buffer(subject, encoding)

  var type = typeof subject
  var length

  if (type === 'number') {
    length = +subject
  } else if (type === 'string') {
    length = Buffer.byteLength(subject, encoding)
  } else if (type === 'object' && subject !== null) {
    // assume object is array-like
    if (subject.type === 'Buffer' && isArray(subject.data)) subject = subject.data
    length = +subject.length
  } else {
    throw new TypeError('must start with number, buffer, array or string')
  }

  if (length > kMaxLength) {
    throw new RangeError('Attempt to allocate Buffer larger than maximum size: 0x' +
      kMaxLength.toString(16) + ' bytes')
  }

  if (length < 0) length = 0
  else length >>>= 0 // coerce to uint32

  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Preferred: Return an augmented `Uint8Array` instance for best performance
    self = Buffer._augment(new Uint8Array(length)) // eslint-disable-line consistent-this
  } else {
    // Fallback: Return THIS instance of Buffer (created by `new`)
    self.length = length
    self._isBuffer = true
  }

  var i
  if (Buffer.TYPED_ARRAY_SUPPORT && typeof subject.byteLength === 'number') {
    // Speed optimization -- use set if we're copying from a typed array
    self._set(subject)
  } else if (isArrayish(subject)) {
    // Treat array-ish objects as a byte array
    if (Buffer.isBuffer(subject)) {
      for (i = 0; i < length; i++) {
        self[i] = subject.readUInt8(i)
      }
    } else {
      for (i = 0; i < length; i++) {
        self[i] = ((subject[i] % 256) + 256) % 256
      }
    }
  } else if (type === 'string') {
    self.write(subject, 0, encoding)
  } else if (type === 'number' && !Buffer.TYPED_ARRAY_SUPPORT) {
    for (i = 0; i < length; i++) {
      self[i] = 0
    }
  }

  if (length > 0 && length <= Buffer.poolSize) self.parent = rootParent

  return self
}

function SlowBuffer (subject, encoding) {
  if (!(this instanceof SlowBuffer)) return new SlowBuffer(subject, encoding)

  var buf = new Buffer(subject, encoding)
  delete buf.parent
  return buf
}

Buffer.isBuffer = function isBuffer (b) {
  return !!(b != null && b._isBuffer)
}

Buffer.compare = function compare (a, b) {
  if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
    throw new TypeError('Arguments must be Buffers')
  }

  if (a === b) return 0

  var x = a.length
  var y = b.length
  for (var i = 0, len = Math.min(x, y); i < len && a[i] === b[i]; i++) {}
  if (i !== len) {
    x = a[i]
    y = b[i]
  }
  if (x < y) return -1
  if (y < x) return 1
  return 0
}

Buffer.isEncoding = function isEncoding (encoding) {
  switch (String(encoding).toLowerCase()) {
    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'binary':
    case 'base64':
    case 'raw':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      return true
    default:
      return false
  }
}

Buffer.concat = function concat (list, totalLength) {
  if (!isArray(list)) throw new TypeError('list argument must be an Array of Buffers.')

  if (list.length === 0) {
    return new Buffer(0)
  } else if (list.length === 1) {
    return list[0]
  }

  var i
  if (totalLength === undefined) {
    totalLength = 0
    for (i = 0; i < list.length; i++) {
      totalLength += list[i].length
    }
  }

  var buf = new Buffer(totalLength)
  var pos = 0
  for (i = 0; i < list.length; i++) {
    var item = list[i]
    item.copy(buf, pos)
    pos += item.length
  }
  return buf
}

Buffer.byteLength = function byteLength (str, encoding) {
  var ret
  str = str + ''
  switch (encoding || 'utf8') {
    case 'ascii':
    case 'binary':
    case 'raw':
      ret = str.length
      break
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      ret = str.length * 2
      break
    case 'hex':
      ret = str.length >>> 1
      break
    case 'utf8':
    case 'utf-8':
      ret = utf8ToBytes(str).length
      break
    case 'base64':
      ret = base64ToBytes(str).length
      break
    default:
      ret = str.length
  }
  return ret
}

// pre-set for values that may exist in the future
Buffer.prototype.length = undefined
Buffer.prototype.parent = undefined

// toString(encoding, start=0, end=buffer.length)
Buffer.prototype.toString = function toString (encoding, start, end) {
  var loweredCase = false

  start = start >>> 0
  end = end === undefined || end === Infinity ? this.length : end >>> 0

  if (!encoding) encoding = 'utf8'
  if (start < 0) start = 0
  if (end > this.length) end = this.length
  if (end <= start) return ''

  while (true) {
    switch (encoding) {
      case 'hex':
        return hexSlice(this, start, end)

      case 'utf8':
      case 'utf-8':
        return utf8Slice(this, start, end)

      case 'ascii':
        return asciiSlice(this, start, end)

      case 'binary':
        return binarySlice(this, start, end)

      case 'base64':
        return base64Slice(this, start, end)

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return utf16leSlice(this, start, end)

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding)
        encoding = (encoding + '').toLowerCase()
        loweredCase = true
    }
  }
}

Buffer.prototype.equals = function equals (b) {
  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
  if (this === b) return true
  return Buffer.compare(this, b) === 0
}

Buffer.prototype.inspect = function inspect () {
  var str = ''
  var max = exports.INSPECT_MAX_BYTES
  if (this.length > 0) {
    str = this.toString('hex', 0, max).match(/.{2}/g).join(' ')
    if (this.length > max) str += ' ... '
  }
  return '<Buffer ' + str + '>'
}

Buffer.prototype.compare = function compare (b) {
  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer')
  if (this === b) return 0
  return Buffer.compare(this, b)
}

Buffer.prototype.indexOf = function indexOf (val, byteOffset) {
  if (byteOffset > 0x7fffffff) byteOffset = 0x7fffffff
  else if (byteOffset < -0x80000000) byteOffset = -0x80000000
  byteOffset >>= 0

  if (this.length === 0) return -1
  if (byteOffset >= this.length) return -1

  // Negative offsets start from the end of the buffer
  if (byteOffset < 0) byteOffset = Math.max(this.length + byteOffset, 0)

  if (typeof val === 'string') {
    if (val.length === 0) return -1 // special case: looking for empty string always fails
    return String.prototype.indexOf.call(this, val, byteOffset)
  }
  if (Buffer.isBuffer(val)) {
    return arrayIndexOf(this, val, byteOffset)
  }
  if (typeof val === 'number') {
    if (Buffer.TYPED_ARRAY_SUPPORT && Uint8Array.prototype.indexOf === 'function') {
      return Uint8Array.prototype.indexOf.call(this, val, byteOffset)
    }
    return arrayIndexOf(this, [ val ], byteOffset)
  }

  function arrayIndexOf (arr, val, byteOffset) {
    var foundIndex = -1
    for (var i = 0; byteOffset + i < arr.length; i++) {
      if (arr[byteOffset + i] === val[foundIndex === -1 ? 0 : i - foundIndex]) {
        if (foundIndex === -1) foundIndex = i
        if (i - foundIndex + 1 === val.length) return byteOffset + foundIndex
      } else {
        foundIndex = -1
      }
    }
    return -1
  }

  throw new TypeError('val must be string, number or Buffer')
}

// `get` will be removed in Node 0.13+
Buffer.prototype.get = function get (offset) {
  console.log('.get() is deprecated. Access using array indexes instead.')
  return this.readUInt8(offset)
}

// `set` will be removed in Node 0.13+
Buffer.prototype.set = function set (v, offset) {
  console.log('.set() is deprecated. Access using array indexes instead.')
  return this.writeUInt8(v, offset)
}

function hexWrite (buf, string, offset, length) {
  offset = Number(offset) || 0
  var remaining = buf.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }

  // must be an even number of digits
  var strLen = string.length
  if (strLen % 2 !== 0) throw new Error('Invalid hex string')

  if (length > strLen / 2) {
    length = strLen / 2
  }
  for (var i = 0; i < length; i++) {
    var parsed = parseInt(string.substr(i * 2, 2), 16)
    if (isNaN(parsed)) throw new Error('Invalid hex string')
    buf[offset + i] = parsed
  }
  return i
}

function utf8Write (buf, string, offset, length) {
  var charsWritten = blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length)
  return charsWritten
}

function asciiWrite (buf, string, offset, length) {
  var charsWritten = blitBuffer(asciiToBytes(string), buf, offset, length)
  return charsWritten
}

function binaryWrite (buf, string, offset, length) {
  return asciiWrite(buf, string, offset, length)
}

function base64Write (buf, string, offset, length) {
  var charsWritten = blitBuffer(base64ToBytes(string), buf, offset, length)
  return charsWritten
}

function utf16leWrite (buf, string, offset, length) {
  var charsWritten = blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length)
  return charsWritten
}

Buffer.prototype.write = function write (string, offset, length, encoding) {
  // Support both (string, offset, length, encoding)
  // and the legacy (string, encoding, offset, length)
  if (isFinite(offset)) {
    if (!isFinite(length)) {
      encoding = length
      length = undefined
    }
  } else {  // legacy
    var swap = encoding
    encoding = offset
    offset = length
    length = swap
  }

  offset = Number(offset) || 0

  if (length < 0 || offset < 0 || offset > this.length) {
    throw new RangeError('attempt to write outside buffer bounds')
  }

  var remaining = this.length - offset
  if (!length) {
    length = remaining
  } else {
    length = Number(length)
    if (length > remaining) {
      length = remaining
    }
  }
  encoding = String(encoding || 'utf8').toLowerCase()

  var ret
  switch (encoding) {
    case 'hex':
      ret = hexWrite(this, string, offset, length)
      break
    case 'utf8':
    case 'utf-8':
      ret = utf8Write(this, string, offset, length)
      break
    case 'ascii':
      ret = asciiWrite(this, string, offset, length)
      break
    case 'binary':
      ret = binaryWrite(this, string, offset, length)
      break
    case 'base64':
      ret = base64Write(this, string, offset, length)
      break
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      ret = utf16leWrite(this, string, offset, length)
      break
    default:
      throw new TypeError('Unknown encoding: ' + encoding)
  }
  return ret
}

Buffer.prototype.toJSON = function toJSON () {
  return {
    type: 'Buffer',
    data: Array.prototype.slice.call(this._arr || this, 0)
  }
}

function base64Slice (buf, start, end) {
  if (start === 0 && end === buf.length) {
    return base64.fromByteArray(buf)
  } else {
    return base64.fromByteArray(buf.slice(start, end))
  }
}

function utf8Slice (buf, start, end) {
  var res = ''
  var tmp = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; i++) {
    if (buf[i] <= 0x7F) {
      res += decodeUtf8Char(tmp) + String.fromCharCode(buf[i])
      tmp = ''
    } else {
      tmp += '%' + buf[i].toString(16)
    }
  }

  return res + decodeUtf8Char(tmp)
}

function asciiSlice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; i++) {
    ret += String.fromCharCode(buf[i] & 0x7F)
  }
  return ret
}

function binarySlice (buf, start, end) {
  var ret = ''
  end = Math.min(buf.length, end)

  for (var i = start; i < end; i++) {
    ret += String.fromCharCode(buf[i])
  }
  return ret
}

function hexSlice (buf, start, end) {
  var len = buf.length

  if (!start || start < 0) start = 0
  if (!end || end < 0 || end > len) end = len

  var out = ''
  for (var i = start; i < end; i++) {
    out += toHex(buf[i])
  }
  return out
}

function utf16leSlice (buf, start, end) {
  var bytes = buf.slice(start, end)
  var res = ''
  for (var i = 0; i < bytes.length; i += 2) {
    res += String.fromCharCode(bytes[i] + bytes[i + 1] * 256)
  }
  return res
}

Buffer.prototype.slice = function slice (start, end) {
  var len = this.length
  start = ~~start
  end = end === undefined ? len : ~~end

  if (start < 0) {
    start += len
    if (start < 0) start = 0
  } else if (start > len) {
    start = len
  }

  if (end < 0) {
    end += len
    if (end < 0) end = 0
  } else if (end > len) {
    end = len
  }

  if (end < start) end = start

  var newBuf
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    newBuf = Buffer._augment(this.subarray(start, end))
  } else {
    var sliceLen = end - start
    newBuf = new Buffer(sliceLen, undefined)
    for (var i = 0; i < sliceLen; i++) {
      newBuf[i] = this[i + start]
    }
  }

  if (newBuf.length) newBuf.parent = this.parent || this

  return newBuf
}

/*
 * Need to make sure that buffer isn't trying to write out of bounds.
 */
function checkOffset (offset, ext, length) {
  if ((offset % 1) !== 0 || offset < 0) throw new RangeError('offset is not uint')
  if (offset + ext > length) throw new RangeError('Trying to access beyond buffer length')
}

Buffer.prototype.readUIntLE = function readUIntLE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var val = this[offset]
  var mul = 1
  var i = 0
  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul
  }

  return val
}

Buffer.prototype.readUIntBE = function readUIntBE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) {
    checkOffset(offset, byteLength, this.length)
  }

  var val = this[offset + --byteLength]
  var mul = 1
  while (byteLength > 0 && (mul *= 0x100)) {
    val += this[offset + --byteLength] * mul
  }

  return val
}

Buffer.prototype.readUInt8 = function readUInt8 (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 1, this.length)
  return this[offset]
}

Buffer.prototype.readUInt16LE = function readUInt16LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  return this[offset] | (this[offset + 1] << 8)
}

Buffer.prototype.readUInt16BE = function readUInt16BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  return (this[offset] << 8) | this[offset + 1]
}

Buffer.prototype.readUInt32LE = function readUInt32LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return ((this[offset]) |
      (this[offset + 1] << 8) |
      (this[offset + 2] << 16)) +
      (this[offset + 3] * 0x1000000)
}

Buffer.prototype.readUInt32BE = function readUInt32BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset] * 0x1000000) +
    ((this[offset + 1] << 16) |
    (this[offset + 2] << 8) |
    this[offset + 3])
}

Buffer.prototype.readIntLE = function readIntLE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var val = this[offset]
  var mul = 1
  var i = 0
  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul
  }
  mul *= 0x80

  if (val >= mul) val -= Math.pow(2, 8 * byteLength)

  return val
}

Buffer.prototype.readIntBE = function readIntBE (offset, byteLength, noAssert) {
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkOffset(offset, byteLength, this.length)

  var i = byteLength
  var mul = 1
  var val = this[offset + --i]
  while (i > 0 && (mul *= 0x100)) {
    val += this[offset + --i] * mul
  }
  mul *= 0x80

  if (val >= mul) val -= Math.pow(2, 8 * byteLength)

  return val
}

Buffer.prototype.readInt8 = function readInt8 (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 1, this.length)
  if (!(this[offset] & 0x80)) return (this[offset])
  return ((0xff - this[offset] + 1) * -1)
}

Buffer.prototype.readInt16LE = function readInt16LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  var val = this[offset] | (this[offset + 1] << 8)
  return (val & 0x8000) ? val | 0xFFFF0000 : val
}

Buffer.prototype.readInt16BE = function readInt16BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 2, this.length)
  var val = this[offset + 1] | (this[offset] << 8)
  return (val & 0x8000) ? val | 0xFFFF0000 : val
}

Buffer.prototype.readInt32LE = function readInt32LE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset]) |
    (this[offset + 1] << 8) |
    (this[offset + 2] << 16) |
    (this[offset + 3] << 24)
}

Buffer.prototype.readInt32BE = function readInt32BE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)

  return (this[offset] << 24) |
    (this[offset + 1] << 16) |
    (this[offset + 2] << 8) |
    (this[offset + 3])
}

Buffer.prototype.readFloatLE = function readFloatLE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)
  return ieee754.read(this, offset, true, 23, 4)
}

Buffer.prototype.readFloatBE = function readFloatBE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 4, this.length)
  return ieee754.read(this, offset, false, 23, 4)
}

Buffer.prototype.readDoubleLE = function readDoubleLE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 8, this.length)
  return ieee754.read(this, offset, true, 52, 8)
}

Buffer.prototype.readDoubleBE = function readDoubleBE (offset, noAssert) {
  if (!noAssert) checkOffset(offset, 8, this.length)
  return ieee754.read(this, offset, false, 52, 8)
}

function checkInt (buf, value, offset, ext, max, min) {
  if (!Buffer.isBuffer(buf)) throw new TypeError('buffer must be a Buffer instance')
  if (value > max || value < min) throw new RangeError('value is out of bounds')
  if (offset + ext > buf.length) throw new RangeError('index out of range')
}

Buffer.prototype.writeUIntLE = function writeUIntLE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkInt(this, value, offset, byteLength, Math.pow(2, 8 * byteLength), 0)

  var mul = 1
  var i = 0
  this[offset] = value & 0xFF
  while (++i < byteLength && (mul *= 0x100)) {
    this[offset + i] = (value / mul) >>> 0 & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeUIntBE = function writeUIntBE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  byteLength = byteLength >>> 0
  if (!noAssert) checkInt(this, value, offset, byteLength, Math.pow(2, 8 * byteLength), 0)

  var i = byteLength - 1
  var mul = 1
  this[offset + i] = value & 0xFF
  while (--i >= 0 && (mul *= 0x100)) {
    this[offset + i] = (value / mul) >>> 0 & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeUInt8 = function writeUInt8 (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0)
  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
  this[offset] = value
  return offset + 1
}

function objectWriteUInt16 (buf, value, offset, littleEndian) {
  if (value < 0) value = 0xffff + value + 1
  for (var i = 0, j = Math.min(buf.length - offset, 2); i < j; i++) {
    buf[offset + i] = (value & (0xff << (8 * (littleEndian ? i : 1 - i)))) >>>
      (littleEndian ? i : 1 - i) * 8
  }
}

Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = value
    this[offset + 1] = (value >>> 8)
  } else {
    objectWriteUInt16(this, value, offset, true)
  }
  return offset + 2
}

Buffer.prototype.writeUInt16BE = function writeUInt16BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 8)
    this[offset + 1] = value
  } else {
    objectWriteUInt16(this, value, offset, false)
  }
  return offset + 2
}

function objectWriteUInt32 (buf, value, offset, littleEndian) {
  if (value < 0) value = 0xffffffff + value + 1
  for (var i = 0, j = Math.min(buf.length - offset, 4); i < j; i++) {
    buf[offset + i] = (value >>> (littleEndian ? i : 3 - i) * 8) & 0xff
  }
}

Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset + 3] = (value >>> 24)
    this[offset + 2] = (value >>> 16)
    this[offset + 1] = (value >>> 8)
    this[offset] = value
  } else {
    objectWriteUInt32(this, value, offset, true)
  }
  return offset + 4
}

Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 24)
    this[offset + 1] = (value >>> 16)
    this[offset + 2] = (value >>> 8)
    this[offset + 3] = value
  } else {
    objectWriteUInt32(this, value, offset, false)
  }
  return offset + 4
}

Buffer.prototype.writeIntLE = function writeIntLE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) {
    checkInt(
      this, value, offset, byteLength,
      Math.pow(2, 8 * byteLength - 1) - 1,
      -Math.pow(2, 8 * byteLength - 1)
    )
  }

  var i = 0
  var mul = 1
  var sub = value < 0 ? 1 : 0
  this[offset] = value & 0xFF
  while (++i < byteLength && (mul *= 0x100)) {
    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeIntBE = function writeIntBE (value, offset, byteLength, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) {
    checkInt(
      this, value, offset, byteLength,
      Math.pow(2, 8 * byteLength - 1) - 1,
      -Math.pow(2, 8 * byteLength - 1)
    )
  }

  var i = byteLength - 1
  var mul = 1
  var sub = value < 0 ? 1 : 0
  this[offset + i] = value & 0xFF
  while (--i >= 0 && (mul *= 0x100)) {
    this[offset + i] = ((value / mul) >> 0) - sub & 0xFF
  }

  return offset + byteLength
}

Buffer.prototype.writeInt8 = function writeInt8 (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80)
  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
  if (value < 0) value = 0xff + value + 1
  this[offset] = value
  return offset + 1
}

Buffer.prototype.writeInt16LE = function writeInt16LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = value
    this[offset + 1] = (value >>> 8)
  } else {
    objectWriteUInt16(this, value, offset, true)
  }
  return offset + 2
}

Buffer.prototype.writeInt16BE = function writeInt16BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 8)
    this[offset + 1] = value
  } else {
    objectWriteUInt16(this, value, offset, false)
  }
  return offset + 2
}

Buffer.prototype.writeInt32LE = function writeInt32LE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = value
    this[offset + 1] = (value >>> 8)
    this[offset + 2] = (value >>> 16)
    this[offset + 3] = (value >>> 24)
  } else {
    objectWriteUInt32(this, value, offset, true)
  }
  return offset + 4
}

Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert) {
  value = +value
  offset = offset >>> 0
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
  if (value < 0) value = 0xffffffff + value + 1
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 24)
    this[offset + 1] = (value >>> 16)
    this[offset + 2] = (value >>> 8)
    this[offset + 3] = value
  } else {
    objectWriteUInt32(this, value, offset, false)
  }
  return offset + 4
}

function checkIEEE754 (buf, value, offset, ext, max, min) {
  if (value > max || value < min) throw new RangeError('value is out of bounds')
  if (offset + ext > buf.length) throw new RangeError('index out of range')
  if (offset < 0) throw new RangeError('index out of range')
}

function writeFloat (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 4, 3.4028234663852886e+38, -3.4028234663852886e+38)
  }
  ieee754.write(buf, value, offset, littleEndian, 23, 4)
  return offset + 4
}

Buffer.prototype.writeFloatLE = function writeFloatLE (value, offset, noAssert) {
  return writeFloat(this, value, offset, true, noAssert)
}

Buffer.prototype.writeFloatBE = function writeFloatBE (value, offset, noAssert) {
  return writeFloat(this, value, offset, false, noAssert)
}

function writeDouble (buf, value, offset, littleEndian, noAssert) {
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 8, 1.7976931348623157E+308, -1.7976931348623157E+308)
  }
  ieee754.write(buf, value, offset, littleEndian, 52, 8)
  return offset + 8
}

Buffer.prototype.writeDoubleLE = function writeDoubleLE (value, offset, noAssert) {
  return writeDouble(this, value, offset, true, noAssert)
}

Buffer.prototype.writeDoubleBE = function writeDoubleBE (value, offset, noAssert) {
  return writeDouble(this, value, offset, false, noAssert)
}

// copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)
Buffer.prototype.copy = function copy (target, target_start, start, end) {
  if (!start) start = 0
  if (!end && end !== 0) end = this.length
  if (target_start >= target.length) target_start = target.length
  if (!target_start) target_start = 0
  if (end > 0 && end < start) end = start

  // Copy 0 bytes; we're done
  if (end === start) return 0
  if (target.length === 0 || this.length === 0) return 0

  // Fatal error conditions
  if (target_start < 0) {
    throw new RangeError('targetStart out of bounds')
  }
  if (start < 0 || start >= this.length) throw new RangeError('sourceStart out of bounds')
  if (end < 0) throw new RangeError('sourceEnd out of bounds')

  // Are we oob?
  if (end > this.length) end = this.length
  if (target.length - target_start < end - start) {
    end = target.length - target_start + start
  }

  var len = end - start

  if (len < 1000 || !Buffer.TYPED_ARRAY_SUPPORT) {
    for (var i = 0; i < len; i++) {
      target[i + target_start] = this[i + start]
    }
  } else {
    target._set(this.subarray(start, start + len), target_start)
  }

  return len
}

// fill(value, start=0, end=buffer.length)
Buffer.prototype.fill = function fill (value, start, end) {
  if (!value) value = 0
  if (!start) start = 0
  if (!end) end = this.length

  if (end < start) throw new RangeError('end < start')

  // Fill 0 bytes; we're done
  if (end === start) return
  if (this.length === 0) return

  if (start < 0 || start >= this.length) throw new RangeError('start out of bounds')
  if (end < 0 || end > this.length) throw new RangeError('end out of bounds')

  var i
  if (typeof value === 'number') {
    for (i = start; i < end; i++) {
      this[i] = value
    }
  } else {
    var bytes = utf8ToBytes(value.toString())
    var len = bytes.length
    for (i = start; i < end; i++) {
      this[i] = bytes[i % len]
    }
  }

  return this
}

/**
 * Creates a new `ArrayBuffer` with the *copied* memory of the buffer instance.
 * Added in Node 0.12. Only available in browsers that support ArrayBuffer.
 */
Buffer.prototype.toArrayBuffer = function toArrayBuffer () {
  if (typeof Uint8Array !== 'undefined') {
    if (Buffer.TYPED_ARRAY_SUPPORT) {
      return (new Buffer(this)).buffer
    } else {
      var buf = new Uint8Array(this.length)
      for (var i = 0, len = buf.length; i < len; i += 1) {
        buf[i] = this[i]
      }
      return buf.buffer
    }
  } else {
    throw new TypeError('Buffer.toArrayBuffer not supported in this browser')
  }
}

// HELPER FUNCTIONS
// ================

var BP = Buffer.prototype

/**
 * Augment a Uint8Array *instance* (not the Uint8Array class!) with Buffer methods
 */
Buffer._augment = function _augment (arr) {
  arr.constructor = Buffer
  arr._isBuffer = true

  // save reference to original Uint8Array set method before overwriting
  arr._set = arr.set

  // deprecated, will be removed in node 0.13+
  arr.get = BP.get
  arr.set = BP.set

  arr.write = BP.write
  arr.toString = BP.toString
  arr.toLocaleString = BP.toString
  arr.toJSON = BP.toJSON
  arr.equals = BP.equals
  arr.compare = BP.compare
  arr.indexOf = BP.indexOf
  arr.copy = BP.copy
  arr.slice = BP.slice
  arr.readUIntLE = BP.readUIntLE
  arr.readUIntBE = BP.readUIntBE
  arr.readUInt8 = BP.readUInt8
  arr.readUInt16LE = BP.readUInt16LE
  arr.readUInt16BE = BP.readUInt16BE
  arr.readUInt32LE = BP.readUInt32LE
  arr.readUInt32BE = BP.readUInt32BE
  arr.readIntLE = BP.readIntLE
  arr.readIntBE = BP.readIntBE
  arr.readInt8 = BP.readInt8
  arr.readInt16LE = BP.readInt16LE
  arr.readInt16BE = BP.readInt16BE
  arr.readInt32LE = BP.readInt32LE
  arr.readInt32BE = BP.readInt32BE
  arr.readFloatLE = BP.readFloatLE
  arr.readFloatBE = BP.readFloatBE
  arr.readDoubleLE = BP.readDoubleLE
  arr.readDoubleBE = BP.readDoubleBE
  arr.writeUInt8 = BP.writeUInt8
  arr.writeUIntLE = BP.writeUIntLE
  arr.writeUIntBE = BP.writeUIntBE
  arr.writeUInt16LE = BP.writeUInt16LE
  arr.writeUInt16BE = BP.writeUInt16BE
  arr.writeUInt32LE = BP.writeUInt32LE
  arr.writeUInt32BE = BP.writeUInt32BE
  arr.writeIntLE = BP.writeIntLE
  arr.writeIntBE = BP.writeIntBE
  arr.writeInt8 = BP.writeInt8
  arr.writeInt16LE = BP.writeInt16LE
  arr.writeInt16BE = BP.writeInt16BE
  arr.writeInt32LE = BP.writeInt32LE
  arr.writeInt32BE = BP.writeInt32BE
  arr.writeFloatLE = BP.writeFloatLE
  arr.writeFloatBE = BP.writeFloatBE
  arr.writeDoubleLE = BP.writeDoubleLE
  arr.writeDoubleBE = BP.writeDoubleBE
  arr.fill = BP.fill
  arr.inspect = BP.inspect
  arr.toArrayBuffer = BP.toArrayBuffer

  return arr
}

var INVALID_BASE64_RE = /[^+\/0-9A-z\-]/g

function base64clean (str) {
  // Node strips out invalid characters like \n and \t from the string, base64-js does not
  str = stringtrim(str).replace(INVALID_BASE64_RE, '')
  // Node converts strings with length < 2 to ''
  if (str.length < 2) return ''
  // Node allows for non-padded base64 strings (missing trailing ===), base64-js does not
  while (str.length % 4 !== 0) {
    str = str + '='
  }
  return str
}

function stringtrim (str) {
  if (str.trim) return str.trim()
  return str.replace(/^\s+|\s+$/g, '')
}

function isArrayish (subject) {
  return isArray(subject) || Buffer.isBuffer(subject) ||
      subject && typeof subject === 'object' &&
      typeof subject.length === 'number'
}

function toHex (n) {
  if (n < 16) return '0' + n.toString(16)
  return n.toString(16)
}

function utf8ToBytes (string, units) {
  units = units || Infinity
  var codePoint
  var length = string.length
  var leadSurrogate = null
  var bytes = []
  var i = 0

  for (; i < length; i++) {
    codePoint = string.charCodeAt(i)

    // is surrogate component
    if (codePoint > 0xD7FF && codePoint < 0xE000) {
      // last char was a lead
      if (leadSurrogate) {
        // 2 leads in a row
        if (codePoint < 0xDC00) {
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          leadSurrogate = codePoint
          continue
        } else {
          // valid surrogate pair
          codePoint = leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00 | 0x10000
          leadSurrogate = null
        }
      } else {
        // no lead yet

        if (codePoint > 0xDBFF) {
          // unexpected trail
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          continue
        } else if (i + 1 === length) {
          // unpaired lead
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
          continue
        } else {
          // valid lead
          leadSurrogate = codePoint
          continue
        }
      }
    } else if (leadSurrogate) {
      // valid bmp char, but last char was a lead
      if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
      leadSurrogate = null
    }

    // encode utf8
    if (codePoint < 0x80) {
      if ((units -= 1) < 0) break
      bytes.push(codePoint)
    } else if (codePoint < 0x800) {
      if ((units -= 2) < 0) break
      bytes.push(
        codePoint >> 0x6 | 0xC0,
        codePoint & 0x3F | 0x80
      )
    } else if (codePoint < 0x10000) {
      if ((units -= 3) < 0) break
      bytes.push(
        codePoint >> 0xC | 0xE0,
        codePoint >> 0x6 & 0x3F | 0x80,
        codePoint & 0x3F | 0x80
      )
    } else if (codePoint < 0x200000) {
      if ((units -= 4) < 0) break
      bytes.push(
        codePoint >> 0x12 | 0xF0,
        codePoint >> 0xC & 0x3F | 0x80,
        codePoint >> 0x6 & 0x3F | 0x80,
        codePoint & 0x3F | 0x80
      )
    } else {
      throw new Error('Invalid code point')
    }
  }

  return bytes
}

function asciiToBytes (str) {
  var byteArray = []
  for (var i = 0; i < str.length; i++) {
    // Node's code seems to be doing this and not & 0x7F..
    byteArray.push(str.charCodeAt(i) & 0xFF)
  }
  return byteArray
}

function utf16leToBytes (str, units) {
  var c, hi, lo
  var byteArray = []
  for (var i = 0; i < str.length; i++) {
    if ((units -= 2) < 0) break

    c = str.charCodeAt(i)
    hi = c >> 8
    lo = c % 256
    byteArray.push(lo)
    byteArray.push(hi)
  }

  return byteArray
}

function base64ToBytes (str) {
  return base64.toByteArray(base64clean(str))
}

function blitBuffer (src, dst, offset, length) {
  for (var i = 0; i < length; i++) {
    if ((i + offset >= dst.length) || (i >= src.length)) break
    dst[i + offset] = src[i]
  }
  return i
}

function decodeUtf8Char (str) {
  try {
    return decodeURIComponent(str)
  } catch (err) {
    return String.fromCharCode(0xFFFD) // UTF 8 invalid char
  }
}

},{"base64-js":31,"ieee754":32,"is-array":33}],31:[function(require,module,exports){
var lookup = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';

;(function (exports) {
	'use strict';

  var Arr = (typeof Uint8Array !== 'undefined')
    ? Uint8Array
    : Array

	var PLUS   = '+'.charCodeAt(0)
	var SLASH  = '/'.charCodeAt(0)
	var NUMBER = '0'.charCodeAt(0)
	var LOWER  = 'a'.charCodeAt(0)
	var UPPER  = 'A'.charCodeAt(0)
	var PLUS_URL_SAFE = '-'.charCodeAt(0)
	var SLASH_URL_SAFE = '_'.charCodeAt(0)

	function decode (elt) {
		var code = elt.charCodeAt(0)
		if (code === PLUS ||
		    code === PLUS_URL_SAFE)
			return 62 // '+'
		if (code === SLASH ||
		    code === SLASH_URL_SAFE)
			return 63 // '/'
		if (code < NUMBER)
			return -1 //no match
		if (code < NUMBER + 10)
			return code - NUMBER + 26 + 26
		if (code < UPPER + 26)
			return code - UPPER
		if (code < LOWER + 26)
			return code - LOWER + 26
	}

	function b64ToByteArray (b64) {
		var i, j, l, tmp, placeHolders, arr

		if (b64.length % 4 > 0) {
			throw new Error('Invalid string. Length must be a multiple of 4')
		}

		// the number of equal signs (place holders)
		// if there are two placeholders, than the two characters before it
		// represent one byte
		// if there is only one, then the three characters before it represent 2 bytes
		// this is just a cheap hack to not do indexOf twice
		var len = b64.length
		placeHolders = '=' === b64.charAt(len - 2) ? 2 : '=' === b64.charAt(len - 1) ? 1 : 0

		// base64 is 4/3 + up to two characters of the original data
		arr = new Arr(b64.length * 3 / 4 - placeHolders)

		// if there are placeholders, only get up to the last complete 4 chars
		l = placeHolders > 0 ? b64.length - 4 : b64.length

		var L = 0

		function push (v) {
			arr[L++] = v
		}

		for (i = 0, j = 0; i < l; i += 4, j += 3) {
			tmp = (decode(b64.charAt(i)) << 18) | (decode(b64.charAt(i + 1)) << 12) | (decode(b64.charAt(i + 2)) << 6) | decode(b64.charAt(i + 3))
			push((tmp & 0xFF0000) >> 16)
			push((tmp & 0xFF00) >> 8)
			push(tmp & 0xFF)
		}

		if (placeHolders === 2) {
			tmp = (decode(b64.charAt(i)) << 2) | (decode(b64.charAt(i + 1)) >> 4)
			push(tmp & 0xFF)
		} else if (placeHolders === 1) {
			tmp = (decode(b64.charAt(i)) << 10) | (decode(b64.charAt(i + 1)) << 4) | (decode(b64.charAt(i + 2)) >> 2)
			push((tmp >> 8) & 0xFF)
			push(tmp & 0xFF)
		}

		return arr
	}

	function uint8ToBase64 (uint8) {
		var i,
			extraBytes = uint8.length % 3, // if we have 1 byte left, pad 2 bytes
			output = "",
			temp, length

		function encode (num) {
			return lookup.charAt(num)
		}

		function tripletToBase64 (num) {
			return encode(num >> 18 & 0x3F) + encode(num >> 12 & 0x3F) + encode(num >> 6 & 0x3F) + encode(num & 0x3F)
		}

		// go through the array every three bytes, we'll deal with trailing stuff later
		for (i = 0, length = uint8.length - extraBytes; i < length; i += 3) {
			temp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2])
			output += tripletToBase64(temp)
		}

		// pad the end with zeros, but make sure to not forget the extra bytes
		switch (extraBytes) {
			case 1:
				temp = uint8[uint8.length - 1]
				output += encode(temp >> 2)
				output += encode((temp << 4) & 0x3F)
				output += '=='
				break
			case 2:
				temp = (uint8[uint8.length - 2] << 8) + (uint8[uint8.length - 1])
				output += encode(temp >> 10)
				output += encode((temp >> 4) & 0x3F)
				output += encode((temp << 2) & 0x3F)
				output += '='
				break
		}

		return output
	}

	exports.toByteArray = b64ToByteArray
	exports.fromByteArray = uint8ToBase64
}(typeof exports === 'undefined' ? (this.base64js = {}) : exports))

},{}],32:[function(require,module,exports){
exports.read = function(buffer, offset, isLE, mLen, nBytes) {
  var e, m,
      eLen = nBytes * 8 - mLen - 1,
      eMax = (1 << eLen) - 1,
      eBias = eMax >> 1,
      nBits = -7,
      i = isLE ? (nBytes - 1) : 0,
      d = isLE ? -1 : 1,
      s = buffer[offset + i];

  i += d;

  e = s & ((1 << (-nBits)) - 1);
  s >>= (-nBits);
  nBits += eLen;
  for (; nBits > 0; e = e * 256 + buffer[offset + i], i += d, nBits -= 8);

  m = e & ((1 << (-nBits)) - 1);
  e >>= (-nBits);
  nBits += mLen;
  for (; nBits > 0; m = m * 256 + buffer[offset + i], i += d, nBits -= 8);

  if (e === 0) {
    e = 1 - eBias;
  } else if (e === eMax) {
    return m ? NaN : ((s ? -1 : 1) * Infinity);
  } else {
    m = m + Math.pow(2, mLen);
    e = e - eBias;
  }
  return (s ? -1 : 1) * m * Math.pow(2, e - mLen);
};

exports.write = function(buffer, value, offset, isLE, mLen, nBytes) {
  var e, m, c,
      eLen = nBytes * 8 - mLen - 1,
      eMax = (1 << eLen) - 1,
      eBias = eMax >> 1,
      rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0),
      i = isLE ? 0 : (nBytes - 1),
      d = isLE ? 1 : -1,
      s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0;

  value = Math.abs(value);

  if (isNaN(value) || value === Infinity) {
    m = isNaN(value) ? 1 : 0;
    e = eMax;
  } else {
    e = Math.floor(Math.log(value) / Math.LN2);
    if (value * (c = Math.pow(2, -e)) < 1) {
      e--;
      c *= 2;
    }
    if (e + eBias >= 1) {
      value += rt / c;
    } else {
      value += rt * Math.pow(2, 1 - eBias);
    }
    if (value * c >= 2) {
      e++;
      c /= 2;
    }

    if (e + eBias >= eMax) {
      m = 0;
      e = eMax;
    } else if (e + eBias >= 1) {
      m = (value * c - 1) * Math.pow(2, mLen);
      e = e + eBias;
    } else {
      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen);
      e = 0;
    }
  }

  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8);

  e = (e << mLen) | m;
  eLen += mLen;
  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8);

  buffer[offset + i - d] |= s * 128;
};

},{}],33:[function(require,module,exports){

/**
 * isArray
 */

var isArray = Array.isArray;

/**
 * toString
 */

var str = Object.prototype.toString;

/**
 * Whether or not the given `val`
 * is an array.
 *
 * example:
 *
 *        isArray([]);
 *        // > true
 *        isArray(arguments);
 *        // > false
 *        isArray('');
 *        // > false
 *
 * @param {mixed} val
 * @return {bool}
 */

module.exports = isArray || function (val) {
  return !! val && '[object Array]' == str.call(val);
};

},{}],34:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

function EventEmitter() {
  this._events = this._events || {};
  this._maxListeners = this._maxListeners || undefined;
}
module.exports = EventEmitter;

// Backwards-compat with node 0.10.x
EventEmitter.EventEmitter = EventEmitter;

EventEmitter.prototype._events = undefined;
EventEmitter.prototype._maxListeners = undefined;

// By default EventEmitters will print a warning if more than 10 listeners are
// added to it. This is a useful default which helps finding memory leaks.
EventEmitter.defaultMaxListeners = 10;

// Obviously not all Emitters should be limited to 10. This function allows
// that to be increased. Set to zero for unlimited.
EventEmitter.prototype.setMaxListeners = function(n) {
  if (!isNumber(n) || n < 0 || isNaN(n))
    throw TypeError('n must be a positive number');
  this._maxListeners = n;
  return this;
};

EventEmitter.prototype.emit = function(type) {
  var er, handler, len, args, i, listeners;

  if (!this._events)
    this._events = {};

  // If there is no 'error' event listener then throw.
  if (type === 'error') {
    if (!this._events.error ||
        (isObject(this._events.error) && !this._events.error.length)) {
      er = arguments[1];
      if (er instanceof Error) {
        throw er; // Unhandled 'error' event
      }
      throw TypeError('Uncaught, unspecified "error" event.');
    }
  }

  handler = this._events[type];

  if (isUndefined(handler))
    return false;

  if (isFunction(handler)) {
    switch (arguments.length) {
      // fast cases
      case 1:
        handler.call(this);
        break;
      case 2:
        handler.call(this, arguments[1]);
        break;
      case 3:
        handler.call(this, arguments[1], arguments[2]);
        break;
      // slower
      default:
        len = arguments.length;
        args = new Array(len - 1);
        for (i = 1; i < len; i++)
          args[i - 1] = arguments[i];
        handler.apply(this, args);
    }
  } else if (isObject(handler)) {
    len = arguments.length;
    args = new Array(len - 1);
    for (i = 1; i < len; i++)
      args[i - 1] = arguments[i];

    listeners = handler.slice();
    len = listeners.length;
    for (i = 0; i < len; i++)
      listeners[i].apply(this, args);
  }

  return true;
};

EventEmitter.prototype.addListener = function(type, listener) {
  var m;

  if (!isFunction(listener))
    throw TypeError('listener must be a function');

  if (!this._events)
    this._events = {};

  // To avoid recursion in the case that type === "newListener"! Before
  // adding it to the listeners, first emit "newListener".
  if (this._events.newListener)
    this.emit('newListener', type,
              isFunction(listener.listener) ?
              listener.listener : listener);

  if (!this._events[type])
    // Optimize the case of one listener. Don't need the extra array object.
    this._events[type] = listener;
  else if (isObject(this._events[type]))
    // If we've already got an array, just append.
    this._events[type].push(listener);
  else
    // Adding the second element, need to change to array.
    this._events[type] = [this._events[type], listener];

  // Check for listener leak
  if (isObject(this._events[type]) && !this._events[type].warned) {
    var m;
    if (!isUndefined(this._maxListeners)) {
      m = this._maxListeners;
    } else {
      m = EventEmitter.defaultMaxListeners;
    }

    if (m && m > 0 && this._events[type].length > m) {
      this._events[type].warned = true;
      console.error('(node) warning: possible EventEmitter memory ' +
                    'leak detected. %d listeners added. ' +
                    'Use emitter.setMaxListeners() to increase limit.',
                    this._events[type].length);
      if (typeof console.trace === 'function') {
        // not supported in IE 10
        console.trace();
      }
    }
  }

  return this;
};

EventEmitter.prototype.on = EventEmitter.prototype.addListener;

EventEmitter.prototype.once = function(type, listener) {
  if (!isFunction(listener))
    throw TypeError('listener must be a function');

  var fired = false;

  function g() {
    this.removeListener(type, g);

    if (!fired) {
      fired = true;
      listener.apply(this, arguments);
    }
  }

  g.listener = listener;
  this.on(type, g);

  return this;
};

// emits a 'removeListener' event iff the listener was removed
EventEmitter.prototype.removeListener = function(type, listener) {
  var list, position, length, i;

  if (!isFunction(listener))
    throw TypeError('listener must be a function');

  if (!this._events || !this._events[type])
    return this;

  list = this._events[type];
  length = list.length;
  position = -1;

  if (list === listener ||
      (isFunction(list.listener) && list.listener === listener)) {
    delete this._events[type];
    if (this._events.removeListener)
      this.emit('removeListener', type, listener);

  } else if (isObject(list)) {
    for (i = length; i-- > 0;) {
      if (list[i] === listener ||
          (list[i].listener && list[i].listener === listener)) {
        position = i;
        break;
      }
    }

    if (position < 0)
      return this;

    if (list.length === 1) {
      list.length = 0;
      delete this._events[type];
    } else {
      list.splice(position, 1);
    }

    if (this._events.removeListener)
      this.emit('removeListener', type, listener);
  }

  return this;
};

EventEmitter.prototype.removeAllListeners = function(type) {
  var key, listeners;

  if (!this._events)
    return this;

  // not listening for removeListener, no need to emit
  if (!this._events.removeListener) {
    if (arguments.length === 0)
      this._events = {};
    else if (this._events[type])
      delete this._events[type];
    return this;
  }

  // emit removeListener for all listeners on all events
  if (arguments.length === 0) {
    for (key in this._events) {
      if (key === 'removeListener') continue;
      this.removeAllListeners(key);
    }
    this.removeAllListeners('removeListener');
    this._events = {};
    return this;
  }

  listeners = this._events[type];

  if (isFunction(listeners)) {
    this.removeListener(type, listeners);
  } else {
    // LIFO order
    while (listeners.length)
      this.removeListener(type, listeners[listeners.length - 1]);
  }
  delete this._events[type];

  return this;
};

EventEmitter.prototype.listeners = function(type) {
  var ret;
  if (!this._events || !this._events[type])
    ret = [];
  else if (isFunction(this._events[type]))
    ret = [this._events[type]];
  else
    ret = this._events[type].slice();
  return ret;
};

EventEmitter.listenerCount = function(emitter, type) {
  var ret;
  if (!emitter._events || !emitter._events[type])
    ret = 0;
  else if (isFunction(emitter._events[type]))
    ret = 1;
  else
    ret = emitter._events[type].length;
  return ret;
};

function isFunction(arg) {
  return typeof arg === 'function';
}

function isNumber(arg) {
  return typeof arg === 'number';
}

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}

function isUndefined(arg) {
  return arg === void 0;
}

},{}],35:[function(require,module,exports){
arguments[4][10][0].apply(exports,arguments)
},{"dup":10}],36:[function(require,module,exports){
arguments[4][24][0].apply(exports,arguments)
},{"dup":24}],37:[function(require,module,exports){
// shim for using process in browser

var process = module.exports = {};
var queue = [];
var draining = false;

function drainQueue() {
    if (draining) {
        return;
    }
    draining = true;
    var currentQueue;
    var len = queue.length;
    while(len) {
        currentQueue = queue;
        queue = [];
        var i = -1;
        while (++i < len) {
            currentQueue[i]();
        }
        len = queue.length;
    }
    draining = false;
}
process.nextTick = function (fun) {
    queue.push(fun);
    if (!draining) {
        setTimeout(drainQueue, 0);
    }
};

process.title = 'browser';
process.browser = true;
process.env = {};
process.argv = [];
process.version = ''; // empty string to avoid regexp issues
process.versions = {};

function noop() {}

process.on = noop;
process.addListener = noop;
process.once = noop;
process.off = noop;
process.removeListener = noop;
process.removeAllListeners = noop;
process.emit = noop;

process.binding = function (name) {
    throw new Error('process.binding is not supported');
};

// TODO(shtylman)
process.cwd = function () { return '/' };
process.chdir = function (dir) {
    throw new Error('process.chdir is not supported');
};
process.umask = function() { return 0; };

},{}],38:[function(require,module,exports){
arguments[4][17][0].apply(exports,arguments)
},{"./lib/_stream_duplex.js":39,"dup":17}],39:[function(require,module,exports){
arguments[4][18][0].apply(exports,arguments)
},{"./_stream_readable":41,"./_stream_writable":43,"_process":37,"core-util-is":44,"dup":18,"inherits":35}],40:[function(require,module,exports){
arguments[4][19][0].apply(exports,arguments)
},{"./_stream_transform":42,"core-util-is":44,"dup":19,"inherits":35}],41:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

module.exports = Readable;

/*<replacement>*/
var isArray = require('isarray');
/*</replacement>*/


/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Readable.ReadableState = ReadableState;

var EE = require('events').EventEmitter;

/*<replacement>*/
if (!EE.listenerCount) EE.listenerCount = function(emitter, type) {
  return emitter.listeners(type).length;
};
/*</replacement>*/

var Stream = require('stream');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var StringDecoder;


/*<replacement>*/
var debug = require('util');
if (debug && debug.debuglog) {
  debug = debug.debuglog('stream');
} else {
  debug = function () {};
}
/*</replacement>*/


util.inherits(Readable, Stream);

function ReadableState(options, stream) {
  var Duplex = require('./_stream_duplex');

  options = options || {};

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  var defaultHwm = options.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.buffer = [];
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = null;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;


  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex)
    this.objectMode = this.objectMode || !!options.readableObjectMode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    if (!StringDecoder)
      StringDecoder = require('string_decoder/').StringDecoder;
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}

function Readable(options) {
  var Duplex = require('./_stream_duplex');

  if (!(this instanceof Readable))
    return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  Stream.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function(chunk, encoding) {
  var state = this._readableState;

  if (util.isString(chunk) && !state.objectMode) {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = new Buffer(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function(chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (util.isNullOrUndefined(chunk)) {
    state.reading = false;
    if (!state.ended)
      onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var e = new Error('stream.unshift() after end event');
      stream.emit('error', e);
    } else {
      if (state.decoder && !addToFront && !encoding)
        chunk = state.decoder.write(chunk);

      if (!addToFront)
        state.reading = false;

      // if we want the data now, just emit it.
      if (state.flowing && state.length === 0 && !state.sync) {
        stream.emit('data', chunk);
        stream.read(0);
      } else {
        // update the buffer info.
        state.length += state.objectMode ? 1 : chunk.length;
        if (addToFront)
          state.buffer.unshift(chunk);
        else
          state.buffer.push(chunk);

        if (state.needReadable)
          emitReadable(stream);
      }

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}



// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended &&
         (state.needReadable ||
          state.length < state.highWaterMark ||
          state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function(enc) {
  if (!StringDecoder)
    StringDecoder = require('string_decoder/').StringDecoder;
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
  return this;
};

// Don't raise the hwm > 128MB
var MAX_HWM = 0x800000;
function roundUpToNextPowerOf2(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2
    n--;
    for (var p = 1; p < 32; p <<= 1) n |= n >> p;
    n++;
  }
  return n;
}

function howMuchToRead(n, state) {
  if (state.length === 0 && state.ended)
    return 0;

  if (state.objectMode)
    return n === 0 ? 0 : 1;

  if (isNaN(n) || util.isNull(n)) {
    // only flow one buffer at a time
    if (state.flowing && state.buffer.length)
      return state.buffer[0].length;
    else
      return state.length;
  }

  if (n <= 0)
    return 0;

  // If we're asking for more than the target buffer level,
  // then raise the water mark.  Bump up to the next highest
  // power of 2, to prevent increasing it excessively in tiny
  // amounts.
  if (n > state.highWaterMark)
    state.highWaterMark = roundUpToNextPowerOf2(n);

  // don't have that much.  return null, unless we've ended.
  if (n > state.length) {
    if (!state.ended) {
      state.needReadable = true;
      return 0;
    } else
      return state.length;
  }

  return n;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function(n) {
  debug('read', n);
  var state = this._readableState;
  var nOrig = n;

  if (!util.isNumber(n) || n > 0)
    state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 &&
      state.needReadable &&
      (state.length >= state.highWaterMark || state.ended)) {
    debug('read: emitReadable', state.length, state.ended);
    if (state.length === 0 && state.ended)
      endReadable(this);
    else
      emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    if (state.length === 0)
      endReadable(this);
    return null;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;
  debug('need readable', doRead);

  // if we currently have less than the highWaterMark, then also read some
  if (state.length === 0 || state.length - n < state.highWaterMark) {
    doRead = true;
    debug('length less than watermark', doRead);
  }

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading) {
    doRead = false;
    debug('reading or ended', doRead);
  }

  if (doRead) {
    debug('do read');
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0)
      state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
  }

  // If _read pushed data synchronously, then `reading` will be false,
  // and we need to re-evaluate how much data we can return to the user.
  if (doRead && !state.reading)
    n = howMuchToRead(nOrig, state);

  var ret;
  if (n > 0)
    ret = fromList(n, state);
  else
    ret = null;

  if (util.isNull(ret)) {
    state.needReadable = true;
    n = 0;
  }

  state.length -= n;

  // If we have nothing in the buffer, then we want to know
  // as soon as we *do* get something into the buffer.
  if (state.length === 0 && !state.ended)
    state.needReadable = true;

  // If we tried to read() past the EOF, then emit end on the next tick.
  if (nOrig !== n && state.ended && state.length === 0)
    endReadable(this);

  if (!util.isNull(ret))
    this.emit('data', ret);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!util.isBuffer(chunk) &&
      !util.isString(chunk) &&
      !util.isNullOrUndefined(chunk) &&
      !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}


function onEofChunk(stream, state) {
  if (state.decoder && !state.ended) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // emit 'readable' now to make sure it gets picked up.
  emitReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (!state.emittedReadable) {
    debug('emitReadable', state.flowing);
    state.emittedReadable = true;
    if (state.sync)
      process.nextTick(function() {
        emitReadable_(stream);
      });
    else
      emitReadable_(stream);
  }
}

function emitReadable_(stream) {
  debug('emit readable');
  stream.emit('readable');
  flow(stream);
}


// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    process.nextTick(function() {
      maybeReadMore_(stream, state);
    });
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended &&
         state.length < state.highWaterMark) {
    debug('maybeReadMore read 0');
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;
    else
      len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function(n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function(dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;
  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);

  var doEnd = (!pipeOpts || pipeOpts.end !== false) &&
              dest !== process.stdout &&
              dest !== process.stderr;

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted)
    process.nextTick(endFn);
  else
    src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    debug('onunpipe');
    if (readable === src) {
      cleanup();
    }
  }

  function onend() {
    debug('onend');
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  function cleanup() {
    debug('cleanup');
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);
    src.removeListener('data', ondata);

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (state.awaitDrain &&
        (!dest._writableState || dest._writableState.needDrain))
      ondrain();
  }

  src.on('data', ondata);
  function ondata(chunk) {
    debug('ondata');
    var ret = dest.write(chunk);
    if (false === ret) {
      debug('false write response, pause',
            src._readableState.awaitDrain);
      src._readableState.awaitDrain++;
      src.pause();
    }
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    debug('onerror', er);
    unpipe();
    dest.removeListener('error', onerror);
    if (EE.listenerCount(dest, 'error') === 0)
      dest.emit('error', er);
  }
  // This is a brutally ugly hack to make sure that our error handler
  // is attached before any userland ones.  NEVER DO THIS.
  if (!dest._events || !dest._events.error)
    dest.on('error', onerror);
  else if (isArray(dest._events.error))
    dest._events.error.unshift(onerror);
  else
    dest._events.error = [onerror, dest._events.error];



  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    debug('onfinish');
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    debug('unpipe');
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    debug('pipe resume');
    src.resume();
  }

  return dest;
};

function pipeOnDrain(src) {
  return function() {
    var state = src._readableState;
    debug('pipeOnDrain', state.awaitDrain);
    if (state.awaitDrain)
      state.awaitDrain--;
    if (state.awaitDrain === 0 && EE.listenerCount(src, 'data')) {
      state.flowing = true;
      flow(src);
    }
  };
}


Readable.prototype.unpipe = function(dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0)
    return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes)
      return this;

    if (!dest)
      dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;
    if (dest)
      dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;

    for (var i = 0; i < len; i++)
      dests[i].emit('unpipe', this);
    return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1)
    return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1)
    state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function(ev, fn) {
  var res = Stream.prototype.on.call(this, ev, fn);

  // If listening to data, and it has not explicitly been paused,
  // then call resume to start the flow of data on the next tick.
  if (ev === 'data' && false !== this._readableState.flowing) {
    this.resume();
  }

  if (ev === 'readable' && this.readable) {
    var state = this._readableState;
    if (!state.readableListening) {
      state.readableListening = true;
      state.emittedReadable = false;
      state.needReadable = true;
      if (!state.reading) {
        var self = this;
        process.nextTick(function() {
          debug('readable nexttick read 0');
          self.read(0);
        });
      } else if (state.length) {
        emitReadable(this, state);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function() {
  var state = this._readableState;
  if (!state.flowing) {
    debug('resume');
    state.flowing = true;
    if (!state.reading) {
      debug('resume read 0');
      this.read(0);
    }
    resume(this, state);
  }
  return this;
};

function resume(stream, state) {
  if (!state.resumeScheduled) {
    state.resumeScheduled = true;
    process.nextTick(function() {
      resume_(stream, state);
    });
  }
}

function resume_(stream, state) {
  state.resumeScheduled = false;
  stream.emit('resume');
  flow(stream);
  if (state.flowing && !state.reading)
    stream.read(0);
}

Readable.prototype.pause = function() {
  debug('call pause flowing=%j', this._readableState.flowing);
  if (false !== this._readableState.flowing) {
    debug('pause');
    this._readableState.flowing = false;
    this.emit('pause');
  }
  return this;
};

function flow(stream) {
  var state = stream._readableState;
  debug('flow', state.flowing);
  if (state.flowing) {
    do {
      var chunk = stream.read();
    } while (null !== chunk && state.flowing);
  }
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function(stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function() {
    debug('wrapped end');
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length)
        self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function(chunk) {
    debug('wrapped data');
    if (state.decoder)
      chunk = state.decoder.write(chunk);
    if (!chunk || !state.objectMode && !chunk.length)
      return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (util.isFunction(stream[i]) && util.isUndefined(this[i])) {
      this[i] = function(method) { return function() {
        return stream[method].apply(stream, arguments);
      }}(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function(ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function(n) {
    debug('wrapped _read', n);
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};



// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
function fromList(n, state) {
  var list = state.buffer;
  var length = state.length;
  var stringMode = !!state.decoder;
  var objectMode = !!state.objectMode;
  var ret;

  // nothing in the list, definitely empty.
  if (list.length === 0)
    return null;

  if (length === 0)
    ret = null;
  else if (objectMode)
    ret = list.shift();
  else if (!n || n >= length) {
    // read it all, truncate the array.
    if (stringMode)
      ret = list.join('');
    else
      ret = Buffer.concat(list, length);
    list.length = 0;
  } else {
    // read just some of it.
    if (n < list[0].length) {
      // just take a part of the first list item.
      // slice is the same for buffers and strings.
      var buf = list[0];
      ret = buf.slice(0, n);
      list[0] = buf.slice(n);
    } else if (n === list[0].length) {
      // first list is a perfect match
      ret = list.shift();
    } else {
      // complex case.
      // we have enough to cover it, but it spans past the first buffer.
      if (stringMode)
        ret = '';
      else
        ret = new Buffer(n);

      var c = 0;
      for (var i = 0, l = list.length; i < l && c < n; i++) {
        var buf = list[0];
        var cpy = Math.min(n - c, buf.length);

        if (stringMode)
          ret += buf.slice(0, cpy);
        else
          buf.copy(ret, c, 0, cpy);

        if (cpy < buf.length)
          list[0] = buf.slice(cpy);
        else
          list.shift();

        c += cpy;
      }
    }
  }

  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0)
    throw new Error('endReadable called on non-empty stream');

  if (!state.endEmitted) {
    state.ended = true;
    process.nextTick(function() {
      // Check that we didn't get one last unshift.
      if (!state.endEmitted && state.length === 0) {
        state.endEmitted = true;
        stream.readable = false;
        stream.emit('end');
      }
    });
  }
}

function forEach (xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf (xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}

}).call(this,require('_process'))
},{"./_stream_duplex":39,"_process":37,"buffer":30,"core-util-is":44,"events":34,"inherits":35,"isarray":36,"stream":49,"string_decoder/":50,"util":29}],42:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.


// a transform stream is a readable/writable stream where you do
// something with the data.  Sometimes it's called a "filter",
// but that's not a great name for it, since that implies a thing where
// some bits pass through, and others are simply ignored.  (That would
// be a valid example of a transform, of course.)
//
// While the output is causally related to the input, it's not a
// necessarily symmetric or synchronous transformation.  For example,
// a zlib stream might take multiple plain-text writes(), and then
// emit a single compressed chunk some time in the future.
//
// Here's how this works:
//
// The Transform stream has all the aspects of the readable and writable
// stream classes.  When you write(chunk), that calls _write(chunk,cb)
// internally, and returns false if there's a lot of pending writes
// buffered up.  When you call read(), that calls _read(n) until
// there's enough pending readable data buffered up.
//
// In a transform stream, the written data is placed in a buffer.  When
// _read(n) is called, it transforms the queued up data, calling the
// buffered _write cb's as it consumes chunks.  If consuming a single
// written chunk would result in multiple output chunks, then the first
// outputted bit calls the readcb, and subsequent chunks just go into
// the read buffer, and will cause it to emit 'readable' if necessary.
//
// This way, back-pressure is actually determined by the reading side,
// since _read has to be called to start processing a new chunk.  However,
// a pathological inflate type of transform can cause excessive buffering
// here.  For example, imagine a stream where every byte of input is
// interpreted as an integer from 0-255, and then results in that many
// bytes of output.  Writing the 4 bytes {ff,ff,ff,ff} would result in
// 1kb of data being output.  In this case, you could write a very small
// amount of input, and end up with a very large amount of output.  In
// such a pathological inflating mechanism, there'd be no way to tell
// the system to stop doing the transform.  A single 4MB write could
// cause the system to run out of memory.
//
// However, even in such a pathological case, only a single written chunk
// would be consumed, and then the rest would wait (un-transformed) until
// the results of the previous transformed chunk were consumed.

module.exports = Transform;

var Duplex = require('./_stream_duplex');

/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

util.inherits(Transform, Duplex);


function TransformState(options, stream) {
  this.afterTransform = function(er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb)
    return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (!util.isNullOrUndefined(data))
    stream.push(data);

  if (cb)
    cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}


function Transform(options) {
  if (!(this instanceof Transform))
    return new Transform(options);

  Duplex.call(this, options);

  this._transformState = new TransformState(options, this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  this.once('prefinish', function() {
    if (util.isFunction(this._flush))
      this._flush(function(er) {
        done(stream, er);
      });
    else
      done(stream);
  });
}

Transform.prototype.push = function(chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function(chunk, encoding, cb) {
  throw new Error('not implemented');
};

Transform.prototype._write = function(chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform ||
        rs.needReadable ||
        rs.length < rs.highWaterMark)
      this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function(n) {
  var ts = this._transformState;

  if (!util.isNull(ts.writechunk) && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};


function done(stream, er) {
  if (er)
    return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var ts = stream._transformState;

  if (ws.length)
    throw new Error('calling transform done when ws.length != 0');

  if (ts.transforming)
    throw new Error('calling transform done when still transforming');

  return stream.push(null);
}

},{"./_stream_duplex":39,"core-util-is":44,"inherits":35}],43:[function(require,module,exports){
(function (process){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

// A bit simpler than readable streams.
// Implement an async ._write(chunk, cb), and it'll handle all
// the drain event emission and buffering.

module.exports = Writable;

/*<replacement>*/
var Buffer = require('buffer').Buffer;
/*</replacement>*/

Writable.WritableState = WritableState;


/*<replacement>*/
var util = require('core-util-is');
util.inherits = require('inherits');
/*</replacement>*/

var Stream = require('stream');

util.inherits(Writable, Stream);

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
}

function WritableState(options, stream) {
  var Duplex = require('./_stream_duplex');

  options = options || {};

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  var defaultHwm = options.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = (hwm || hwm === 0) ? hwm : defaultHwm;

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex)
    this.objectMode = this.objectMode || !!options.writableObjectMode;

  // cast to ints.
  this.highWaterMark = ~~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // when true all writes will be buffered until .uncork() call
  this.corked = 0;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function(er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.buffer = [];

  // number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted
  this.pendingcb = 0;

  // emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams
  this.prefinished = false;

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;
}

function Writable(options) {
  var Duplex = require('./_stream_duplex');

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex))
    return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  Stream.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function() {
  this.emit('error', new Error('Cannot pipe. Not readable.'));
};


function writeAfterEnd(stream, state, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  process.nextTick(function() {
    cb(er);
  });
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;
  if (!util.isBuffer(chunk) &&
      !util.isString(chunk) &&
      !util.isNullOrUndefined(chunk) &&
      !state.objectMode) {
    var er = new TypeError('Invalid non-string/buffer chunk');
    stream.emit('error', er);
    process.nextTick(function() {
      cb(er);
    });
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function(chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (util.isFunction(encoding)) {
    cb = encoding;
    encoding = null;
  }

  if (util.isBuffer(chunk))
    encoding = 'buffer';
  else if (!encoding)
    encoding = state.defaultEncoding;

  if (!util.isFunction(cb))
    cb = function() {};

  if (state.ended)
    writeAfterEnd(this, state, cb);
  else if (validChunk(this, state, chunk, cb)) {
    state.pendingcb++;
    ret = writeOrBuffer(this, state, chunk, encoding, cb);
  }

  return ret;
};

Writable.prototype.cork = function() {
  var state = this._writableState;

  state.corked++;
};

Writable.prototype.uncork = function() {
  var state = this._writableState;

  if (state.corked) {
    state.corked--;

    if (!state.writing &&
        !state.corked &&
        !state.finished &&
        !state.bufferProcessing &&
        state.buffer.length)
      clearBuffer(this, state);
  }
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode &&
      state.decodeStrings !== false &&
      util.isString(chunk)) {
    chunk = new Buffer(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);
  if (util.isBuffer(chunk))
    encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret)
    state.needDrain = true;

  if (state.writing || state.corked)
    state.buffer.push(new WriteReq(chunk, encoding, cb));
  else
    doWrite(stream, state, false, len, chunk, encoding, cb);

  return ret;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (writev)
    stream._writev(chunk, state.onwrite);
  else
    stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  if (sync)
    process.nextTick(function() {
      state.pendingcb--;
      cb(er);
    });
  else {
    state.pendingcb--;
    cb(er);
  }

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er)
    onwriteError(stream, state, sync, er, cb);
  else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(stream, state);

    if (!finished &&
        !state.corked &&
        !state.bufferProcessing &&
        state.buffer.length) {
      clearBuffer(stream, state);
    }

    if (sync) {
      process.nextTick(function() {
        afterWrite(stream, state, finished, cb);
      });
    } else {
      afterWrite(stream, state, finished, cb);
    }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished)
    onwriteDrain(stream, state);
  state.pendingcb--;
  cb();
  finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}


// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;

  if (stream._writev && state.buffer.length > 1) {
    // Fast case, write everything using _writev()
    var cbs = [];
    for (var c = 0; c < state.buffer.length; c++)
      cbs.push(state.buffer[c].callback);

    // count the one we are adding, as well.
    // TODO(isaacs) clean this up
    state.pendingcb++;
    doWrite(stream, state, true, state.length, state.buffer, '', function(err) {
      for (var i = 0; i < cbs.length; i++) {
        state.pendingcb--;
        cbs[i](err);
      }
    });

    // Clear buffer
    state.buffer = [];
  } else {
    // Slow case, write chunks one-by-one
    for (var c = 0; c < state.buffer.length; c++) {
      var entry = state.buffer[c];
      var chunk = entry.chunk;
      var encoding = entry.encoding;
      var cb = entry.callback;
      var len = state.objectMode ? 1 : chunk.length;

      doWrite(stream, state, false, len, chunk, encoding, cb);

      // if we didn't call the onwrite immediately, then
      // it means that we need to wait until it does.
      // also, that means that the chunk and cb are currently
      // being processed, so move the buffer counter past them.
      if (state.writing) {
        c++;
        break;
      }
    }

    if (c < state.buffer.length)
      state.buffer = state.buffer.slice(c);
    else
      state.buffer.length = 0;
  }

  state.bufferProcessing = false;
}

Writable.prototype._write = function(chunk, encoding, cb) {
  cb(new Error('not implemented'));

};

Writable.prototype._writev = null;

Writable.prototype.end = function(chunk, encoding, cb) {
  var state = this._writableState;

  if (util.isFunction(chunk)) {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (util.isFunction(encoding)) {
    cb = encoding;
    encoding = null;
  }

  if (!util.isNullOrUndefined(chunk))
    this.write(chunk, encoding);

  // .end() fully uncorks
  if (state.corked) {
    state.corked = 1;
    this.uncork();
  }

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished)
    endWritable(this, state, cb);
};


function needFinish(stream, state) {
  return (state.ending &&
          state.length === 0 &&
          !state.finished &&
          !state.writing);
}

function prefinish(stream, state) {
  if (!state.prefinished) {
    state.prefinished = true;
    stream.emit('prefinish');
  }
}

function finishMaybe(stream, state) {
  var need = needFinish(stream, state);
  if (need) {
    if (state.pendingcb === 0) {
      prefinish(stream, state);
      state.finished = true;
      stream.emit('finish');
    } else
      prefinish(stream, state);
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished)
      process.nextTick(cb);
    else
      stream.once('finish', cb);
  }
  state.ended = true;
}

}).call(this,require('_process'))
},{"./_stream_duplex":39,"_process":37,"buffer":30,"core-util-is":44,"inherits":35,"stream":49}],44:[function(require,module,exports){
arguments[4][23][0].apply(exports,arguments)
},{"buffer":30,"dup":23}],45:[function(require,module,exports){
module.exports = require("./lib/_stream_passthrough.js")

},{"./lib/_stream_passthrough.js":40}],46:[function(require,module,exports){
exports = module.exports = require('./lib/_stream_readable.js');
exports.Stream = require('stream');
exports.Readable = exports;
exports.Writable = require('./lib/_stream_writable.js');
exports.Duplex = require('./lib/_stream_duplex.js');
exports.Transform = require('./lib/_stream_transform.js');
exports.PassThrough = require('./lib/_stream_passthrough.js');

},{"./lib/_stream_duplex.js":39,"./lib/_stream_passthrough.js":40,"./lib/_stream_readable.js":41,"./lib/_stream_transform.js":42,"./lib/_stream_writable.js":43,"stream":49}],47:[function(require,module,exports){
module.exports = require("./lib/_stream_transform.js")

},{"./lib/_stream_transform.js":42}],48:[function(require,module,exports){
module.exports = require("./lib/_stream_writable.js")

},{"./lib/_stream_writable.js":43}],49:[function(require,module,exports){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

module.exports = Stream;

var EE = require('events').EventEmitter;
var inherits = require('inherits');

inherits(Stream, EE);
Stream.Readable = require('readable-stream/readable.js');
Stream.Writable = require('readable-stream/writable.js');
Stream.Duplex = require('readable-stream/duplex.js');
Stream.Transform = require('readable-stream/transform.js');
Stream.PassThrough = require('readable-stream/passthrough.js');

// Backwards-compat with node 0.4.x
Stream.Stream = Stream;



// old-style streams.  Note that the pipe method (the only relevant
// part of this class) is overridden in the Readable class.

function Stream() {
  EE.call(this);
}

Stream.prototype.pipe = function(dest, options) {
  var source = this;

  function ondata(chunk) {
    if (dest.writable) {
      if (false === dest.write(chunk) && source.pause) {
        source.pause();
      }
    }
  }

  source.on('data', ondata);

  function ondrain() {
    if (source.readable && source.resume) {
      source.resume();
    }
  }

  dest.on('drain', ondrain);

  // If the 'end' option is not supplied, dest.end() will be called when
  // source gets the 'end' or 'close' events.  Only dest.end() once.
  if (!dest._isStdio && (!options || options.end !== false)) {
    source.on('end', onend);
    source.on('close', onclose);
  }

  var didOnEnd = false;
  function onend() {
    if (didOnEnd) return;
    didOnEnd = true;

    dest.end();
  }


  function onclose() {
    if (didOnEnd) return;
    didOnEnd = true;

    if (typeof dest.destroy === 'function') dest.destroy();
  }

  // don't leave dangling pipes when there are errors.
  function onerror(er) {
    cleanup();
    if (EE.listenerCount(this, 'error') === 0) {
      throw er; // Unhandled stream error in pipe.
    }
  }

  source.on('error', onerror);
  dest.on('error', onerror);

  // remove all the event listeners that were added.
  function cleanup() {
    source.removeListener('data', ondata);
    dest.removeListener('drain', ondrain);

    source.removeListener('end', onend);
    source.removeListener('close', onclose);

    source.removeListener('error', onerror);
    dest.removeListener('error', onerror);

    source.removeListener('end', cleanup);
    source.removeListener('close', cleanup);

    dest.removeListener('close', cleanup);
  }

  source.on('end', cleanup);
  source.on('close', cleanup);

  dest.on('close', cleanup);

  dest.emit('pipe', source);

  // Allow for unix-like usage: A.pipe(B).pipe(C)
  return dest;
};

},{"events":34,"inherits":35,"readable-stream/duplex.js":38,"readable-stream/passthrough.js":45,"readable-stream/readable.js":46,"readable-stream/transform.js":47,"readable-stream/writable.js":48}],50:[function(require,module,exports){
arguments[4][25][0].apply(exports,arguments)
},{"buffer":30,"dup":25}],51:[function(require,module,exports){
module.exports = function isBuffer(arg) {
  return arg && typeof arg === 'object'
    && typeof arg.copy === 'function'
    && typeof arg.fill === 'function'
    && typeof arg.readUInt8 === 'function';
}
},{}],52:[function(require,module,exports){
(function (process,global){
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

var formatRegExp = /%[sdj%]/g;
exports.format = function(f) {
  if (!isString(f)) {
    var objects = [];
    for (var i = 0; i < arguments.length; i++) {
      objects.push(inspect(arguments[i]));
    }
    return objects.join(' ');
  }

  var i = 1;
  var args = arguments;
  var len = args.length;
  var str = String(f).replace(formatRegExp, function(x) {
    if (x === '%%') return '%';
    if (i >= len) return x;
    switch (x) {
      case '%s': return String(args[i++]);
      case '%d': return Number(args[i++]);
      case '%j':
        try {
          return JSON.stringify(args[i++]);
        } catch (_) {
          return '[Circular]';
        }
      default:
        return x;
    }
  });
  for (var x = args[i]; i < len; x = args[++i]) {
    if (isNull(x) || !isObject(x)) {
      str += ' ' + x;
    } else {
      str += ' ' + inspect(x);
    }
  }
  return str;
};


// Mark that a method should not be used.
// Returns a modified function which warns once by default.
// If --no-deprecation is set, then it is a no-op.
exports.deprecate = function(fn, msg) {
  // Allow for deprecating things in the process of starting up.
  if (isUndefined(global.process)) {
    return function() {
      return exports.deprecate(fn, msg).apply(this, arguments);
    };
  }

  if (process.noDeprecation === true) {
    return fn;
  }

  var warned = false;
  function deprecated() {
    if (!warned) {
      if (process.throwDeprecation) {
        throw new Error(msg);
      } else if (process.traceDeprecation) {
        console.trace(msg);
      } else {
        console.error(msg);
      }
      warned = true;
    }
    return fn.apply(this, arguments);
  }

  return deprecated;
};


var debugs = {};
var debugEnviron;
exports.debuglog = function(set) {
  if (isUndefined(debugEnviron))
    debugEnviron = process.env.NODE_DEBUG || '';
  set = set.toUpperCase();
  if (!debugs[set]) {
    if (new RegExp('\\b' + set + '\\b', 'i').test(debugEnviron)) {
      var pid = process.pid;
      debugs[set] = function() {
        var msg = exports.format.apply(exports, arguments);
        console.error('%s %d: %s', set, pid, msg);
      };
    } else {
      debugs[set] = function() {};
    }
  }
  return debugs[set];
};


/**
 * Echos the value of a value. Trys to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Object} opts Optional options object that alters the output.
 */
/* legacy: obj, showHidden, depth, colors*/
function inspect(obj, opts) {
  // default options
  var ctx = {
    seen: [],
    stylize: stylizeNoColor
  };
  // legacy...
  if (arguments.length >= 3) ctx.depth = arguments[2];
  if (arguments.length >= 4) ctx.colors = arguments[3];
  if (isBoolean(opts)) {
    // legacy...
    ctx.showHidden = opts;
  } else if (opts) {
    // got an "options" object
    exports._extend(ctx, opts);
  }
  // set default options
  if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
  if (isUndefined(ctx.depth)) ctx.depth = 2;
  if (isUndefined(ctx.colors)) ctx.colors = false;
  if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
  if (ctx.colors) ctx.stylize = stylizeWithColor;
  return formatValue(ctx, obj, ctx.depth);
}
exports.inspect = inspect;


// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
  'bold' : [1, 22],
  'italic' : [3, 23],
  'underline' : [4, 24],
  'inverse' : [7, 27],
  'white' : [37, 39],
  'grey' : [90, 39],
  'black' : [30, 39],
  'blue' : [34, 39],
  'cyan' : [36, 39],
  'green' : [32, 39],
  'magenta' : [35, 39],
  'red' : [31, 39],
  'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
  'special': 'cyan',
  'number': 'yellow',
  'boolean': 'yellow',
  'undefined': 'grey',
  'null': 'bold',
  'string': 'green',
  'date': 'magenta',
  // "name": intentionally not styling
  'regexp': 'red'
};


function stylizeWithColor(str, styleType) {
  var style = inspect.styles[styleType];

  if (style) {
    return '\u001b[' + inspect.colors[style][0] + 'm' + str +
           '\u001b[' + inspect.colors[style][1] + 'm';
  } else {
    return str;
  }
}


function stylizeNoColor(str, styleType) {
  return str;
}


function arrayToHash(array) {
  var hash = {};

  array.forEach(function(val, idx) {
    hash[val] = true;
  });

  return hash;
}


function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (ctx.customInspect &&
      value &&
      isFunction(value.inspect) &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== exports.inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes, ctx);
    if (!isString(ret)) {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // Look up the keys of the object.
  var keys = Object.keys(value);
  var visibleKeys = arrayToHash(keys);

  if (ctx.showHidden) {
    keys = Object.getOwnPropertyNames(value);
  }

  // IE doesn't make error fields non-enumerable
  // http://msdn.microsoft.com/en-us/library/ie/dww52sbt(v=vs.94).aspx
  if (isError(value)
      && (keys.indexOf('message') >= 0 || keys.indexOf('description') >= 0)) {
    return formatError(value);
  }

  // Some type of object without properties can be shortcutted.
  if (keys.length === 0) {
    if (isFunction(value)) {
      var name = value.name ? ': ' + value.name : '';
      return ctx.stylize('[Function' + name + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
  }

  var base = '', array = false, braces = ['{', '}'];

  // Make Array say that they are Array
  if (isArray(value)) {
    array = true;
    braces = ['[', ']'];
  }

  // Make functions say that they are functions
  if (isFunction(value)) {
    var n = value.name ? ': ' + value.name : '';
    base = ' [Function' + n + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toUTCString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    base = ' ' + formatError(value);
  }

  if (keys.length === 0 && (!array || value.length == 0)) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output;
  if (array) {
    output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
  } else {
    output = keys.map(function(key) {
      return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
    });
  }

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}


function formatPrimitive(ctx, value) {
  if (isUndefined(value))
    return ctx.stylize('undefined', 'undefined');
  if (isString(value)) {
    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                                             .replace(/'/g, "\\'")
                                             .replace(/\\"/g, '"') + '\'';
    return ctx.stylize(simple, 'string');
  }
  if (isNumber(value))
    return ctx.stylize('' + value, 'number');
  if (isBoolean(value))
    return ctx.stylize('' + value, 'boolean');
  // For some reason typeof null is "object", so special case here.
  if (isNull(value))
    return ctx.stylize('null', 'null');
}


function formatError(value) {
  return '[' + Error.prototype.toString.call(value) + ']';
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (hasOwnProperty(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  keys.forEach(function(key) {
    if (!key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str, desc;
  desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
  if (desc.get) {
    if (desc.set) {
      str = ctx.stylize('[Getter/Setter]', 'special');
    } else {
      str = ctx.stylize('[Getter]', 'special');
    }
  } else {
    if (desc.set) {
      str = ctx.stylize('[Setter]', 'special');
    }
  }
  if (!hasOwnProperty(visibleKeys, key)) {
    name = '[' + key + ']';
  }
  if (!str) {
    if (ctx.seen.indexOf(desc.value) < 0) {
      if (isNull(recurseTimes)) {
        str = formatValue(ctx, desc.value, null);
      } else {
        str = formatValue(ctx, desc.value, recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = str.split('\n').map(function(line) {
            return '  ' + line;
          }).join('\n').substr(2);
        } else {
          str = '\n' + str.split('\n').map(function(line) {
            return '   ' + line;
          }).join('\n');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (isUndefined(name)) {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'");
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
  var numLinesEst = 0;
  var length = output.reduce(function(prev, cur) {
    numLinesEst++;
    if (cur.indexOf('\n') >= 0) numLinesEst++;
    return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           (base === '' ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}


// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
  return Array.isArray(ar);
}
exports.isArray = isArray;

function isBoolean(arg) {
  return typeof arg === 'boolean';
}
exports.isBoolean = isBoolean;

function isNull(arg) {
  return arg === null;
}
exports.isNull = isNull;

function isNullOrUndefined(arg) {
  return arg == null;
}
exports.isNullOrUndefined = isNullOrUndefined;

function isNumber(arg) {
  return typeof arg === 'number';
}
exports.isNumber = isNumber;

function isString(arg) {
  return typeof arg === 'string';
}
exports.isString = isString;

function isSymbol(arg) {
  return typeof arg === 'symbol';
}
exports.isSymbol = isSymbol;

function isUndefined(arg) {
  return arg === void 0;
}
exports.isUndefined = isUndefined;

function isRegExp(re) {
  return isObject(re) && objectToString(re) === '[object RegExp]';
}
exports.isRegExp = isRegExp;

function isObject(arg) {
  return typeof arg === 'object' && arg !== null;
}
exports.isObject = isObject;

function isDate(d) {
  return isObject(d) && objectToString(d) === '[object Date]';
}
exports.isDate = isDate;

function isError(e) {
  return isObject(e) &&
      (objectToString(e) === '[object Error]' || e instanceof Error);
}
exports.isError = isError;

function isFunction(arg) {
  return typeof arg === 'function';
}
exports.isFunction = isFunction;

function isPrimitive(arg) {
  return arg === null ||
         typeof arg === 'boolean' ||
         typeof arg === 'number' ||
         typeof arg === 'string' ||
         typeof arg === 'symbol' ||  // ES6 symbol
         typeof arg === 'undefined';
}
exports.isPrimitive = isPrimitive;

exports.isBuffer = require('./support/isBuffer');

function objectToString(o) {
  return Object.prototype.toString.call(o);
}


function pad(n) {
  return n < 10 ? '0' + n.toString(10) : n.toString(10);
}


var months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
              'Oct', 'Nov', 'Dec'];

// 26 Feb 16:19:34
function timestamp() {
  var d = new Date();
  var time = [pad(d.getHours()),
              pad(d.getMinutes()),
              pad(d.getSeconds())].join(':');
  return [d.getDate(), months[d.getMonth()], time].join(' ');
}


// log is just a thin wrapper to console.log that prepends a timestamp
exports.log = function() {
  console.log('%s - %s', timestamp(), exports.format.apply(exports, arguments));
};


/**
 * Inherit the prototype methods from one constructor into another.
 *
 * The Function.prototype.inherits from lang.js rewritten as a standalone
 * function (not on Function.prototype). NOTE: If this file is to be loaded
 * during bootstrapping this function needs to be rewritten using some native
 * functions as prototype setup using normal JavaScript does not work as
 * expected during bootstrapping (see mirror.js in r114903).
 *
 * @param {function} ctor Constructor function which needs to inherit the
 *     prototype.
 * @param {function} superCtor Constructor function to inherit prototype from.
 */
exports.inherits = require('inherits');

exports._extend = function(origin, add) {
  // Don't do anything if add isn't an object
  if (!add || !isObject(add)) return origin;

  var keys = Object.keys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
};

function hasOwnProperty(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

}).call(this,require('_process'),typeof global !== "undefined" ? global : typeof self !== "undefined" ? self : typeof window !== "undefined" ? window : {})
},{"./support/isBuffer":51,"_process":37,"inherits":35}]},{},[27])(27)
});