/** @license MIT License (c) copyright 2010-2014 original author or authors */ /** * Promises/A+ and when() implementation * when is part of the cujoJS family of libraries (http://cujojs.com/) * @author Brian Cavalier * @author John Hann */ (function(define) { 'use strict'; define(function (require) { var timed = require('./lib/decorators/timed'); var array = require('./lib/decorators/array'); var flow = require('./lib/decorators/flow'); var fold = require('./lib/decorators/fold'); var inspect = require('./lib/decorators/inspect'); var generate = require('./lib/decorators/iterate'); var progress = require('./lib/decorators/progress'); var withThis = require('./lib/decorators/with'); var unhandledRejection = require('./lib/decorators/unhandledRejection'); var TimeoutError = require('./lib/TimeoutError'); var Promise = [array, flow, fold, generate, progress, inspect, withThis, timed, unhandledRejection] .reduce(function(Promise, feature) { return feature(Promise); }, require('./lib/Promise')); var apply = require('./lib/apply')(Promise); // Public API when.promise = promise; // Create a pending promise when.resolve = Promise.resolve; // Create a resolved promise when.reject = Promise.reject; // Create a rejected promise when.lift = lift; // lift a function to return promises when['try'] = attempt; // call a function and return a promise when.attempt = attempt; // alias for when.try when.iterate = Promise.iterate; // DEPRECATED (use cujojs/most streams) Generate a stream of promises when.unfold = Promise.unfold; // DEPRECATED (use cujojs/most streams) Generate a stream of promises when.join = join; // Join 2 or more promises when.all = all; // Resolve a list of promises when.settle = settle; // Settle a list of promises when.any = lift(Promise.any); // One-winner race when.some = lift(Promise.some); // Multi-winner race when.race = lift(Promise.race); // First-to-settle race when.map = map; // Array.map() for promises when.filter = filter; // Array.filter() for promises when.reduce = lift(Promise.reduce); // Array.reduce() for promises when.reduceRight = lift(Promise.reduceRight); // Array.reduceRight() for promises when.isPromiseLike = isPromiseLike; // Is something promise-like, aka thenable when.Promise = Promise; // Promise constructor when.defer = defer; // Create a {promise, resolve, reject} tuple // Error types when.TimeoutError = TimeoutError; /** * Get a trusted promise for x, or by transforming x with onFulfilled * * @param {*} x * @param {function?} onFulfilled callback to be called when x is * successfully fulfilled. If promiseOrValue is an immediate value, callback * will be invoked immediately. * @param {function?} onRejected callback to be called when x is * rejected. * @param {function?} onProgress callback to be called when progress updates * are issued for x. @deprecated * @returns {Promise} a new promise that will fulfill with the return * value of callback or errback or the completion value of promiseOrValue if * callback and/or errback is not supplied. */ function when(x, onFulfilled, onRejected, onProgress) { var p = Promise.resolve(x); if (arguments.length < 2) { return p; } return p.then(onFulfilled, onRejected, onProgress); } /** * Creates a new promise whose fate is determined by resolver. * @param {function} resolver function(resolve, reject, notify) * @returns {Promise} promise whose fate is determine by resolver */ function promise(resolver) { return new Promise(resolver); } /** * Lift the supplied function, creating a version of f that returns * promises, and accepts promises as arguments. * @param {function} f * @returns {Function} version of f that returns promises */ function lift(f) { return function() { for(var i=0, l=arguments.length, a=new Array(l); i<l; ++i) { a[i] = arguments[i]; } return apply(f, this, a); }; } /** * Call f in a future turn, with the supplied args, and return a promise * for the result. * @param {function} f * @returns {Promise} */ function attempt(f /*, args... */) { /*jshint validthis:true */ for(var i=0, l=arguments.length-1, a=new Array(l); i<l; ++i) { a[i] = arguments[i+1]; } return apply(f, this, a); } /** * Creates a {promise, resolver} pair, either or both of which * may be given out safely to consumers. * @return {{promise: Promise, resolve: function, reject: function, notify: function}} */ function defer() { return new Deferred(); } function Deferred() { var p = Promise._defer(); function resolve(x) { p._handler.resolve(x); } function reject(x) { p._handler.reject(x); } function notify(x) { p._handler.notify(x); } this.promise = p; this.resolve = resolve; this.reject = reject; this.notify = notify; this.resolver = { resolve: resolve, reject: reject, notify: notify }; } /** * Determines if x is promise-like, i.e. a thenable object * NOTE: Will return true for *any thenable object*, and isn't truly * safe, since it may attempt to access the `then` property of x (i.e. * clever/malicious getters may do weird things) * @param {*} x anything * @returns {boolean} true if x is promise-like */ function isPromiseLike(x) { return x && typeof x.then === 'function'; } /** * Return a promise that will resolve only once all the supplied arguments * have resolved. The resolution value of the returned promise will be an array * containing the resolution values of each of the arguments. * @param {...*} arguments may be a mix of promises and values * @returns {Promise} */ function join(/* ...promises */) { return Promise.all(arguments); } /** * Return a promise that will fulfill once all input promises have * fulfilled, or reject when any one input promise rejects. * @param {array|Promise} promises array (or promise for an array) of promises * @returns {Promise} */ function all(promises) { return when(promises, Promise.all); } /** * Return a promise that will always fulfill with an array containing * the outcome states of all input promises. The returned promise * will only reject if `promises` itself is a rejected promise. * @param {array|Promise} promises array (or promise for an array) of promises * @returns {Promise} promise for array of settled state descriptors */ function settle(promises) { return when(promises, Promise.settle); } /** * Promise-aware array map function, similar to `Array.prototype.map()`, * but input array may contain promises or values. * @param {Array|Promise} promises array of anything, may contain promises and values * @param {function(x:*, index:Number):*} mapFunc map function which may * return a promise or value * @returns {Promise} promise that will fulfill with an array of mapped values * or reject if any input promise rejects. */ function map(promises, mapFunc) { return when(promises, function(promises) { return Promise.map(promises, mapFunc); }); } /** * Filter the provided array of promises using the provided predicate. Input may * contain promises and values * @param {Array|Promise} promises array of promises and values * @param {function(x:*, index:Number):boolean} predicate filtering predicate. * Must return truthy (or promise for truthy) for items to retain. * @returns {Promise} promise that will fulfill with an array containing all items * for which predicate returned truthy. */ function filter(promises, predicate) { return when(promises, function(promises) { return Promise.filter(promises, predicate); }); } return when; }); })(typeof define === 'function' && define.amd ? define : function (factory) { module.exports = factory(require); });