MediaClass.js

/*! MediaClass.js v0.0.1 | MIT License | github.com/jonathantneal/MediaClass */

(function (global, documentElement) {
	function getMediaFeatures() {
		media.width = global.innerWidth || documentElement.clientWidth;
		media.height = global.innerHeight || documentElement.clientHeight;
		media.aspectRatio = media.width / media.height;
		media.orientation = media.width > media.height ? "landscape" : "portrait";

		media.deviceWidth = screen.width;
		media.deviceHeight = screen.height;
		media.deviceAspectRatio = media.deviceWidth / media.deviceHeight;
		media.deviceOrientation = media.deviceWidth > media.deviceHeight ? "landscape" : "portrait";
	}

	function getElementMediaFeatures(element) {
		var coordinates = element.getBoundingClientRect();

		media.thisWidth = coordinates.width || coordinates.right - coordinates.left;
		media.thisHeight = coordinates.height || coordinates.bottom - coordinates.top;
		media.thisAspectRatio = media.thisWidth / media.thisHeight,
		media.thisOrientation = media.thisWidth > media.thisHeight ? "landscape" : "portrait";
	}

	function evalMediaQuery(query) {
		return Function("d", "return(" + query
		.replace(/\(|\)/g, "")
		.replace(/\s*,\s*/g, ") || (")
		.replace(/\s+and\s+/gi, " && ")
		.replace(/min-(.*?):/gi, "$1>=")
		.replace(/max-(.*?):/gi, "$1<=")
		.replace(/above-(.*?):/gi, "$1>")
		.replace(/below-(.*?):/gi, "$1<")
		.replace(/min-|max-/gi, "")
		.replace(/(all|screen|print)/, "d.$1")
		.replace(/:/g, "==")
		.replace(/([\w-]+)\s*([<>=]+)\s*(\w+)/g, function ($0, $1, $2, $3) {
			return "d." + toCamelCase($1) + $2 + parseCSSNumber($3);
		})
		.replace(/([<>=]+)([A-z][\w-]*)/g, '$1"$2"') + ")")(media);
	}

	function toCamelCase(value) {
		return value.toLowerCase().replace(/-[a-z]/g, function ($0) {
			return $0[1].toUpperCase();
		});
	}

	function parseCSSNumber(value) {
		return value.replace(/([\d\.]+)(%|em|in|pt|px)/, function ($0, $1, $2) {
			return ($2 == "em") ? $1 * 16 : ($2 == "in") ? $1 * 96 : ($2 == "pt") ? $1 * 96 / 72 : ($2 == "%") ? $1 / (scope.innerWidth || documentElement.clientWidth) : $1;
		});
	}

	var
	changed = false,
	media = { all: true, screen: true, print: false },
	eventMethod = ("addEventListener" in global ? "addEventListener " : "attachEvent on").split(" "),
	eventType = "blur orientationchange resize".split(" "),
	eventIndex = 0;

	for (;eventType[eventIndex]; ++eventIndex) {
		global[eventMethod[0]](eventMethod[1] + eventType[eventIndex], getMediaFeatures);
	}

	var
	LastIndexOf = Array.prototype.lastIndexOf || function (value) { for (var length = this.length; --length > -1;) if (this[length] == value) break; return length; };
	addClass = function (element, className) {
		var classList = element.className ? element.className.split(/\s+/) : [], index = LastIndexOf.call(classList, className);
		if (index < 0) element.className = classList.concat(className).join(" ");
	},
	removeClass = function (element, className) {
		var classList = element.className ? element.className.split(/\s+/) : [], index = LastIndexOf.call(classList, className);
		if (index > -1 && classList.splice(index, 1)) element.className = classList.join(" ");
	},
	mediaList = [];

	function mediaLoop() {
		for (var i = 0, item, match, element; item = mediaList[i]; ++i) {
			match = item.media.match(/(.+?):media\((.+?)\)/);

			if (match) {
				if (documentElement.querySelectorAll) {
					all = documentElement.querySelectorAll(match[1]);

					for (var index = 0; element = all[index]; ++index) {
						/this/.test(match[2]) && getElementMediaFeatures(element);

						evalMediaQuery(match[2]) ? addClass(element, item.className) : removeClass(element, item.className);
					}
				}
			} else {
				evalMediaQuery(item.media) ? addClass(documentElement, item.className) : removeClass(documentElement, item.className);
			}
		}
	}

	function MediaQuery(className, mediaQuery) {
		var self = this, enabled = 1;

		self.className = className;
		self.media = mediaQuery;
		self.index = mediaList.push(self) - 1;
		self.enable = function () { if (!enabled) { mediaList.push(self); enabled = true; } };
		self.disable = function () { if (enabled) { mediaList.splice(self.index, 1); enabled = false; } };
	}

	global.MediaClass = function (className, mediaQuery) {
		var mq = new MediaQuery(className, mediaQuery);

		mediaList.push(mq);

		return mq;
	};

	getMediaFeatures(); mediaLoop(); setInterval(mediaLoop, 66);
})(this, document.documentElement);