337 lines
7.7 KiB
JavaScript
337 lines
7.7 KiB
JavaScript
(function(global) {
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global.createPromiseCapability = function() {
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var promiseCapability = {};
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var promise = new Promise(function(resolve, reject) {
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promiseCapability.resolve = resolve;
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promiseCapability.reject = reject;
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});
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promiseCapability.promise = promise;
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return promiseCapability;
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};
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//
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// Check for native Promise and it has correct interface
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//
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var NativePromise = global['Promise'];
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var nativePromiseSupported =
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NativePromise &&
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// Some of these methods are missing from
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// Firefox/Chrome experimental implementations
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'resolve' in NativePromise &&
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'reject' in NativePromise &&
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'all' in NativePromise &&
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'race' in NativePromise &&
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// Older version of the spec had a resolver object
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// as the arg rather than a function
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(function() {
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var resolve;
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new NativePromise(function(r) {
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resolve = r;
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});
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return typeof resolve === 'function';
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})();
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//
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// export if necessary
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//
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if (typeof exports !== 'undefined' && exports) {
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// node.js
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exports.Promise = nativePromiseSupported ? NativePromise : Promise;
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exports.Polyfill = Promise;
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} else {
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// AMD
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if (typeof define == 'function' && define.amd) {
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define(function() {
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return nativePromiseSupported ? NativePromise : Promise;
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});
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} else {
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// in browser add to global
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if (!nativePromiseSupported)
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global['Promise'] = Promise;
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}
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}
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//
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// Polyfill
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//
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var PENDING = 'pending';
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var SEALED = 'sealed';
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var FULFILLED = 'fulfilled';
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var REJECTED = 'rejected';
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var NOOP = function() {};
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function isArray(value) {
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return Object.prototype.toString.call(value) === '[object Array]';
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}
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// async calls
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var asyncSetTimer = typeof setImmediate !== 'undefined' ? setImmediate : setTimeout;
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var asyncQueue = [];
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var asyncTimer;
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function asyncFlush() {
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// run promise callbacks
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for (var i = 0; i < asyncQueue.length; i++)
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asyncQueue[i][0](asyncQueue[i][1]);
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// reset async asyncQueue
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asyncQueue = [];
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asyncTimer = false;
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}
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function asyncCall(callback, arg) {
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asyncQueue.push([callback, arg]);
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if (!asyncTimer) {
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asyncTimer = true;
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asyncSetTimer(asyncFlush, 0);
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}
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}
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function invokeResolver(resolver, promise) {
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function resolvePromise(value) {
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resolve(promise, value);
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}
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function rejectPromise(reason) {
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reject(promise, reason);
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}
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try {
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resolver(resolvePromise, rejectPromise);
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} catch (e) {
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rejectPromise(e);
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}
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}
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function invokeCallback(subscriber) {
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var owner = subscriber.owner;
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var settled = owner.state_;
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var value = owner.data_;
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var callback = subscriber[settled];
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var promise = subscriber.then;
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if (typeof callback === 'function') {
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settled = FULFILLED;
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try {
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value = callback(value);
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} catch (e) {
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reject(promise, e);
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}
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}
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if (!handleThenable(promise, value)) {
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if (settled === FULFILLED)
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resolve(promise, value);
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if (settled === REJECTED)
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reject(promise, value);
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}
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}
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function handleThenable(promise, value) {
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var resolved;
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try {
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if (promise === value)
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throw new TypeError('A promises callback cannot return that same promise.');
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if (value && (typeof value === 'function' || typeof value === 'object')) {
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var then = value.then; // then should be retrived only once
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if (typeof then === 'function') {
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then.call(value, function(val) {
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if (!resolved) {
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resolved = true;
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if (value !== val)
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resolve(promise, val);
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else
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fulfill(promise, val);
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}
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}, function(reason) {
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if (!resolved) {
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resolved = true;
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reject(promise, reason);
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}
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});
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return true;
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}
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}
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} catch (e) {
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if (!resolved)
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reject(promise, e);
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return true;
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}
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return false;
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}
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function resolve(promise, value) {
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if (promise === value || !handleThenable(promise, value))
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fulfill(promise, value);
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}
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function fulfill(promise, value) {
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if (promise.state_ === PENDING) {
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promise.state_ = SEALED;
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promise.data_ = value;
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asyncCall(publishFulfillment, promise);
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}
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}
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function reject(promise, reason) {
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if (promise.state_ === PENDING) {
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promise.state_ = SEALED;
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promise.data_ = reason;
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asyncCall(publishRejection, promise);
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}
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}
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function publish(promise) {
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var callbacks = promise.then_;
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promise.then_ = undefined;
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for (var i = 0; i < callbacks.length; i++) {
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invokeCallback(callbacks[i]);
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}
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}
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function publishFulfillment(promise) {
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promise.state_ = FULFILLED;
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publish(promise);
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}
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function publishRejection(promise) {
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promise.state_ = REJECTED;
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publish(promise);
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}
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/**
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* @class
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*/
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function Promise(resolver) {
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if (typeof resolver !== 'function')
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throw new TypeError('Promise constructor takes a function argument');
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if (this instanceof Promise === false)
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throw new TypeError('Failed to construct \'Promise\': Please use the \'new\' operator, this object constructor cannot be called as a function.');
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this.then_ = [];
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invokeResolver(resolver, this);
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}
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Promise.prototype = {
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constructor: Promise,
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state_: PENDING,
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then_: null,
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data_: undefined,
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then: function(onFulfillment, onRejection) {
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var subscriber = {
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owner: this,
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then: new this.constructor(NOOP),
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fulfilled: onFulfillment,
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rejected: onRejection
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};
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if (this.state_ === FULFILLED || this.state_ === REJECTED) {
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// already resolved, call callback async
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asyncCall(invokeCallback, subscriber);
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} else {
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// subscribe
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this.then_.push(subscriber);
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}
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return subscriber.then;
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},
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'catch': function(onRejection) {
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return this.then(null, onRejection);
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}
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};
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Promise.all = function(promises) {
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var Class = this;
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if (!isArray(promises))
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throw new TypeError('You must pass an array to Promise.all().');
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return new Class(function(resolve, reject) {
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var results = [];
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var remaining = 0;
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function resolver(index) {
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remaining++;
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return function(value) {
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results[index] = value;
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if (!--remaining)
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resolve(results);
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};
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}
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for (var i = 0, promise; i < promises.length; i++) {
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promise = promises[i];
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if (promise && typeof promise.then === 'function')
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promise.then(resolver(i), reject);
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else
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results[i] = promise;
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}
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if (!remaining)
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resolve(results);
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});
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};
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Promise.race = function(promises) {
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var Class = this;
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if (!isArray(promises))
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throw new TypeError('You must pass an array to Promise.race().');
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return new Class(function(resolve, reject) {
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for (var i = 0, promise; i < promises.length; i++) {
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promise = promises[i];
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if (promise && typeof promise.then === 'function')
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promise.then(resolve, reject);
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else
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resolve(promise);
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}
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});
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};
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Promise.resolve = function(value) {
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var Class = this;
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if (value && typeof value === 'object' && value.constructor === Class)
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return value;
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return new Class(function(resolve) {
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resolve(value);
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});
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};
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Promise.reject = function(reason) {
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var Class = this;
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return new Class(function(resolve, reject) {
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reject(reason);
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});
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};
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})(typeof window != 'undefined' ? window : typeof global != 'undefined' ? global : typeof self != 'undefined' ? self : this); |