187 lines
4.7 KiB
JavaScript
187 lines
4.7 KiB
JavaScript
'use strict';
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//This file contains the ES6 extensions to the core Promises/A+ API
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var Promise = require('./core.js');
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module.exports = Promise;
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/* Static Functions */
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var TRUE = valuePromise(true);
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var FALSE = valuePromise(false);
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var NULL = valuePromise(null);
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var UNDEFINED = valuePromise(undefined);
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var ZERO = valuePromise(0);
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var EMPTYSTRING = valuePromise('');
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function valuePromise(value) {
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var p = new Promise(Promise._D);
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p._y = 1;
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p._z = value;
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return p;
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}
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Promise.resolve = function (value) {
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if (value instanceof Promise) return value;
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if (value === null) return NULL;
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if (value === undefined) return UNDEFINED;
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if (value === true) return TRUE;
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if (value === false) return FALSE;
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if (value === 0) return ZERO;
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if (value === '') return EMPTYSTRING;
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if (typeof value === 'object' || typeof value === 'function') {
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try {
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var then = value.then;
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if (typeof then === 'function') {
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return new Promise(then.bind(value));
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}
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} catch (ex) {
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return new Promise(function (resolve, reject) {
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reject(ex);
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});
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}
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}
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return valuePromise(value);
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};
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var iterableToArray = function (iterable) {
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if (typeof Array.from === 'function') {
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// ES2015+, iterables exist
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iterableToArray = Array.from;
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return Array.from(iterable);
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}
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// ES5, only arrays and array-likes exist
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iterableToArray = function (x) { return Array.prototype.slice.call(x); };
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return Array.prototype.slice.call(iterable);
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}
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Promise.all = function (arr) {
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var args = iterableToArray(arr);
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return new Promise(function (resolve, reject) {
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if (args.length === 0) return resolve([]);
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var remaining = args.length;
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function res(i, val) {
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if (val && (typeof val === 'object' || typeof val === 'function')) {
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if (val instanceof Promise && val.then === Promise.prototype.then) {
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while (val._y === 3) {
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val = val._z;
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}
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if (val._y === 1) return res(i, val._z);
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if (val._y === 2) reject(val._z);
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val.then(function (val) {
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res(i, val);
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}, reject);
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return;
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} else {
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var then = val.then;
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if (typeof then === 'function') {
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var p = new Promise(then.bind(val));
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p.then(function (val) {
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res(i, val);
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}, reject);
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return;
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}
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}
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}
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args[i] = val;
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if (--remaining === 0) {
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resolve(args);
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}
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}
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for (var i = 0; i < args.length; i++) {
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res(i, args[i]);
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}
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});
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};
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function onSettledFulfill(value) {
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return { status: 'fulfilled', value: value };
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}
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function onSettledReject(reason) {
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return { status: 'rejected', reason: reason };
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}
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function mapAllSettled(item) {
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if(item && (typeof item === 'object' || typeof item === 'function')){
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if(item instanceof Promise && item.then === Promise.prototype.then){
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return item.then(onSettledFulfill, onSettledReject);
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}
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var then = item.then;
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if (typeof then === 'function') {
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return new Promise(then.bind(item)).then(onSettledFulfill, onSettledReject)
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}
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}
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return onSettledFulfill(item);
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}
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Promise.allSettled = function (iterable) {
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return Promise.all(iterableToArray(iterable).map(mapAllSettled));
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};
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Promise.reject = function (value) {
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return new Promise(function (resolve, reject) {
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reject(value);
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});
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};
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Promise.race = function (values) {
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return new Promise(function (resolve, reject) {
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iterableToArray(values).forEach(function(value){
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Promise.resolve(value).then(resolve, reject);
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});
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});
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};
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/* Prototype Methods */
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Promise.prototype['catch'] = function (onRejected) {
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return this.then(null, onRejected);
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};
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function getAggregateError(errors){
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if(typeof AggregateError === 'function'){
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return new AggregateError(errors,'All promises were rejected');
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}
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var error = new Error('All promises were rejected');
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error.name = 'AggregateError';
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error.errors = errors;
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return error;
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}
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Promise.any = function promiseAny(values) {
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return new Promise(function(resolve, reject) {
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var promises = iterableToArray(values);
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var hasResolved = false;
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var rejectionReasons = [];
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function resolveOnce(value) {
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if (!hasResolved) {
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hasResolved = true;
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resolve(value);
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}
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}
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function rejectionCheck(reason) {
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rejectionReasons.push(reason);
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if (rejectionReasons.length === promises.length) {
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reject(getAggregateError(rejectionReasons));
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}
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}
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if(promises.length === 0){
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reject(getAggregateError(rejectionReasons));
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} else {
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promises.forEach(function(value){
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Promise.resolve(value).then(resolveOnce, rejectionCheck);
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});
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}
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});
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};
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