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292 lines
5.8 KiB
292 lines
5.8 KiB
'use strict'; |
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var PENDING = 'pending'; |
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var SETTLED = 'settled'; |
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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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var isNode = typeof global !== 'undefined' && typeof global.process !== 'undefined' && typeof global.process.emit === 'function'; |
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var asyncSetTimer = typeof setImmediate === 'undefined' ? setTimeout : setImmediate; |
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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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} |
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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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} |
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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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} |
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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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} |
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if (value && (typeof value === 'function' || typeof value === 'object')) { |
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// then should be retrieved only once |
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var then = value.then; |
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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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fulfill(promise, val); |
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} else { |
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resolve(promise, val); |
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} |
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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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} |
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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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} |
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function fulfill(promise, value) { |
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if (promise._state === PENDING) { |
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promise._state = SETTLED; |
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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 = SETTLED; |
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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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promise._then = promise._then.forEach(invokeCallback); |
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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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if (!promise._handled && isNode) { |
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global.process.emit('unhandledRejection', promise._data, promise); |
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} |
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} |
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function notifyRejectionHandled(promise) { |
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global.process.emit('rejectionHandled', 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 resolver ' + resolver + ' is not a function'); |
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} |
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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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} |
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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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_handled: false, |
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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 ((onRejection || onFulfillment) && !this._handled) { |
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this._handled = true; |
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if (this._state === REJECTED && isNode) { |
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asyncCall(notifyRejectionHandled, this); |
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} |
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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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if (!Array.isArray(promises)) { |
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throw new TypeError('You must pass an array to Promise.all().'); |
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} |
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return new Promise(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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} |
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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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} |
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if (!remaining) { |
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resolve(results); |
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} |
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}); |
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}; |
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Promise.race = function (promises) { |
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if (!Array.isArray(promises)) { |
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throw new TypeError('You must pass an array to Promise.race().'); |
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} |
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return new Promise(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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}; |
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Promise.resolve = function (value) { |
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if (value && typeof value === 'object' && value.constructor === Promise) { |
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return value; |
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} |
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return new Promise(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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return new Promise(function (resolve, reject) { |
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reject(reason); |
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}); |
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}; |
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module.exports = Promise;
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