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/**
@license
Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
*/
function MakePromise (asap) {
function Promise(fn) {
if (typeof this !== 'object' || typeof fn !== 'function') throw new TypeError();
this._state = null;
this._value = null;
this._deferreds = []
doResolve(fn, resolve.bind(this), reject.bind(this));
}
function handle(deferred) {
var me = this;
if (this._state === null) {
this._deferreds.push(deferred);
return
}
asap(function() {
var cb = me._state ? deferred.onFulfilled : deferred.onRejected
if (typeof cb !== 'function') {
(me._state ? deferred.resolve : deferred.reject)(me._value);
return;
}
var ret;
try {
ret = cb(me._value);
}
catch (e) {
deferred.reject(e);
return;
}
deferred.resolve(ret);
})
}
function resolve(newValue) {
try { //Promise Resolution Procedure: https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
if (newValue === this) throw new TypeError();
if (newValue && (typeof newValue === 'object' || typeof newValue === 'function')) {
var then = newValue.then;
if (typeof then === 'function') {
doResolve(then.bind(newValue), resolve.bind(this), reject.bind(this));
return;
}
}
this._state = true;
this._value = newValue;
finale.call(this);
} catch (e) { reject.call(this, e); }
}
function reject(newValue) {
this._state = false;
this._value = newValue;
finale.call(this);
}
function finale() {
for (var i = 0, len = this._deferreds.length; i < len; i++) {
handle.call(this, this._deferreds[i]);
}
this._deferreds = null;
}
/**
* Take a potentially misbehaving resolver function and make sure
* onFulfilled and onRejected are only called once.
*
* Makes no guarantees about asynchrony.
*/
function doResolve(fn, onFulfilled, onRejected) {
var done = false;
try {
fn(function (value) {
if (done) return;
done = true;
onFulfilled(value);
}, function (reason) {
if (done) return;
done = true;
onRejected(reason);
})
} catch (ex) {
if (done) return;
done = true;
onRejected(ex);
}
}
Promise.prototype['catch'] = function (onRejected) {
return this.then(null, onRejected);
};
Promise.prototype.then = function(onFulfilled, onRejected) {
var me = this;
return new Promise(function(resolve, reject) {
handle.call(me, {
onFulfilled: onFulfilled,
onRejected: onRejected,
resolve: resolve,
reject: reject
});
})
};
Promise.resolve = function (value) {
if (value && typeof value === 'object' && value.constructor === Promise) {
return value;
}
return new Promise(function (resolve) {
resolve(value);
});
};
Promise.reject = function (value) {
return new Promise(function (resolve, reject) {
reject(value);
});
};
return Promise;
}
if (typeof module !== 'undefined') {
module.exports = MakePromise;
}
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