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index.js
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index.js
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function emit(type, elm) {
if (Array.isArray(elm.evnQue[type])) {
for (var i = 0; i < elm.evnQue[type].length; i++) {
elm.evnQue[type][i]();
}
}
}
function bind(elm, type, handle) {
if (!elm.evnQue[type]) elm.evnQue[type] = [];
elm.evnQue[type].push(handle);
}
function Promise(executor) {
this.pm = {
status: 'pending',
value: '',
reason: ''
};
this.evnQue = {};
var self = this;
if (typeof executor != 'function') throw new TypeError('Promise executor is not Function');
executor(function(value) {
if (self.pm.status === 'pending') {
self.pm.value = value;
self.pm.status = 'fulfilled';
emit('resolve', self);
}
}, function(reason) {
if (self.pm.status === 'pending') {
self.pm.reason = reason;
self.pm.status = 'rejected';
emit('reject', self);
}
});
}
Promise.resolve = function(pro, x) {
if (pro.pm.status == 'rejected') return;
if (x && x.constructor == Promise) {
if (x.pm.status == 'fulfilled') {
Promise.resolve(pro, x.pm.value);
return;
} else if (x.pm.status == 'rejected') {
Promise.reject(pro, x.pm.reason);
return;
} else {
pro.pm = x.pm;
x.evnQue = pro.evnQue;
}
} else if (x && (typeof x == 'object' || typeof x == 'function') && ('then' in x)) {
var then = null;
try {
then = x.then;
} catch (e) {
Promise.reject(pro, e);
return;
}
if (typeof then != 'function') {
pro.pm.value = x;
pro.pm.status = 'fulfilled';
} else {
var times = 0;
try {
then.call(x, function(value) {
if (times > 0) return;
Promise.resolve(pro, value);
times++;
}, function(reason) {
if (times > 0) return;
Promise.reject(pro, reason);
times++;
});
} catch (e) {
if (times === 0) Promise.reject(pro, e);
times++;
}
return;
}
} else {
pro.pm.value = x;
pro.pm.status = 'fulfilled';
}
if (pro.pm.status == 'fulfilled') emit('resolve', pro);
else if (pro.pm.status == 'rejected') emit('reject', pro);
};
Promise.reject = function(pro, e) {
if (pro.pm.status == 'fulfilled') return;
pro.pm.status = 'rejected';
pro.pm.reason = e;
emit('reject', pro);
};
Promise.prototype.then = function(onRes, onRej) {
var next = new Promise(function(res, rej) {});
var self = this;
if (self.pm.status == 'pending') {
bind(self, 'resolve', handle);
bind(self, 'reject', handle);
} else {
handle();
}
return next;
function handle() {
setTimeout(function() {
try {
var result = null;
if (self.pm.status == 'fulfilled') {
if (typeof onRes != 'function') {
Promise.resolve(next, self.pm.value);
return;
}
result = onRes(self.pm.value);
} else if (self.pm.status == 'rejected') {
if (typeof onRej != 'function') {
Promise.reject(next, self.pm.reason);
return;
}
result = onRej(self.pm.reason);
}
if (result == next)
Promise.reject(next, new TypeError());
else
Promise.resolve(next, result);
} catch (e) {
Promise.reject(next, e);
}
});
}
};
module.exports = Promise;