promise polyfill
This commit is contained in:
Leo Horie
parent
41ac2bf002
commit
76d5d9ef2f
3 changed files with 589 additions and 0 deletions
74
promise/promise.js
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74
promise/promise.js
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"use strict"
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function Promise(executor) {
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if (!(this instanceof Promise)) throw new Error("Promise must be called with `new`")
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if (typeof executor !== "function") throw new Error("executor must be a function")
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var self = this, resolvers = [], rejectors = [], resolveCurrent = handler(resolvers, true), rejectCurrent = handler(rejectors, false)
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function handler(list, shouldAbsorb) {
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return function execute(value) {
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if (shouldAbsorb && (typeof value === "object" || typeof value === "function") && typeof value.then === "function") {
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if (value === self) rejectCurrent(new Error("Promise cannot be resolved with itself"))
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value.then(execute, rejectCurrent)
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}
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else {
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setTimeout(function() {
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for (var i = 0; i < list.length; i++) list[i](value)
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resolvers.length = 0, rejectors.length = 0
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}, 0)
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}
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}
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}
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this._instance = {resolvers: resolvers, rejectors: rejectors}
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try {executor(resolveCurrent, rejectCurrent)} catch (e) {rejectCurrent(e)}
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}
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Promise.prototype.then = function(onFulfilled, onRejection) {
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function handle(callback, list) {
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if (typeof callback === "function") {
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list.push(function(value) {
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try {resolveNext(callback(value))} catch (e) {if (rejectNext) rejectNext(e)}
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})
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}
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}
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var resolveNext, rejectNext
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handle(onFulfilled, this._instance.resolvers), handle(onRejection, this._instance.rejectors)
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return new Promise(function(resolve, reject) {resolveNext = resolve, rejectNext = reject})
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}
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Promise.prototype.catch = function(onRejection) {
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return this.then(null, onRejection)
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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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return new Promise(function(resolve, reject) {resolve(value)})
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}
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Promise.reject = function(value) {
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return new Promise(function(resolve, reject) {reject(value)})
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}
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Promise.all = function(list) {
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return new Promise(function(resolve, reject) {
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var total = list.length, count = 0, values = []
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for (var i = 0; i < list.length; i++) {
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new function(i) {
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function consume(value) {
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count++
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values[i] = value
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if (count === total) resolve(values)
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}
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if ((typeof list[i] === "object" || typeof list[i] === "function") && typeof list[i].then === "function") {
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list[i].then(consume, reject)
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}
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else consume(list[i])
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}(i)
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}
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})
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}
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Promise.race = function(list) {
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return new Promise(function(resolve, reject) {
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for (var i = 0; i < list.length; i++) {
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list[i].then(resolve, reject)
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}
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})
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}
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module.exports = Promise
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16
promise/tests/index.html
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16
promise/tests/index.html
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<!doctype html>
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<html>
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<head>
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<meta charset="utf-8">
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</head>
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<body>
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<script src="../../module/module.js"></script>
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<script src="../../ospec/ospec.js"></script>
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<script src="../../test-utils/callAsync.js"></script>
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<script src="../../promise/promise.js"></script>
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<script src="test-promise.js"></script>
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<script>require("../../ospec/ospec").run()</script>
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</body>
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</html>
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499
promise/tests/test-promise.js
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499
promise/tests/test-promise.js
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"use strict"
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var o = require("../../ospec/ospec")
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var callAsync = require("../../test-utils/callAsync")
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var Promise = require("../../promise/promise")
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o.spec("promise", function() {
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o.spec("constructor", function() {
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o("constructor throws if called without new", function(done) {
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try {Promise(function() {})} catch(e) {done()}
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})
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o("constructor throws if called without executor", function(done) {
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try {new Promise()} catch(e) {done()}
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})
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o("constructor has correct methods", function() {
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o(typeof Promise.prototype.then).equals("function")
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o(typeof Promise.prototype.catch).equals("function")
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o(typeof Promise.resolve).equals("function")
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o(typeof Promise.reject).equals("function")
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o(typeof Promise.race).equals("function")
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o(typeof Promise.all).equals("function")
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})
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})
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o.spec("return value", function() {
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o("static resolve returns promise", function() {
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var promise = Promise.resolve()
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o(promise instanceof Promise).equals(true)
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})
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o("static resolve returns promise", function() {
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var promise = Promise.reject()
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promise.catch(function() {})
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o(promise instanceof Promise).equals(true)
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})
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o("static resolve with promise input returns same promise", function() {
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var resolved = Promise.resolve(1)
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var promise = Promise.resolve(resolved)
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o(promise).equals(resolved)
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})
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o("then returns promise", function(done) {
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var promise = Promise.resolve(1)
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promise.then(function(value) {
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o(value).equals(1)
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}).then(done)
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})
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o("catch returns promise", function(done) {
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var promise = Promise.reject(1)
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promise.catch(function(value) {
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o(value).equals(1)
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}).then(done)
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})
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})
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o.spec("resolve", function() {
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o("resolves once", function(done) {
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var callCount = 0
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var promise = new Promise(function(resolve, reject) {
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resolve(1)
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resolve(2)
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callAsync(function() {resolve(3)})
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})
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promise.then(function(value) {
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callCount++
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o(value).equals(1)
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o(callCount).equals(1)
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done()
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})
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})
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o("does not reject after resolve", function(done) {
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var promise = new Promise(function(resolve, reject) {
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resolve(1)
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reject(2)
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callAsync(function() {reject(3)})
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})
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promise.then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("resolves asynchronously", function(done) {
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var state = 0
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var promise = Promise.resolve()
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state = 1
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promise.then(function(value) {
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o(state).equals(2)
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done()
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})
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state = 2
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})
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o("resolves via static method", function(done) {
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var promise = Promise.resolve(1)
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promise.then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("resolves asynchronously via executor", function(done) {
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var promise = new Promise(function(resolve, reject) {
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callAsync(function() {resolve(1)})
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})
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promise.then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("downstreams correctly", function(done) {
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var promise = Promise.resolve(1)
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var a = promise.then(function(value) {return value + 1})
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var b = promise.then(function(value) {return value + 2})
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a.then(function(aValue) {
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b.then(function(bValue) {
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o(aValue).equals(2)
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o(bValue).equals(3)
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done()
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})
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})
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})
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o("cannot resolve to itself", function(done) {
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var promise = new Promise(function(resolve) {
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callAsync(function() {resolve(promise)})
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})
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promise.then(null, done)
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})
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})
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o.spec("reject", function() {
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o("rejects once", function(done) {
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var callCount = 0
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var promise = new Promise(function(resolve, reject) {
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reject(1)
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reject(2)
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callAsync(function() {reject(3)})
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})
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promise.then(null, function(value) {
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callCount++
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o(value).equals(1)
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o(callCount).equals(1)
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done()
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})
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})
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o("does not resolve after reject", function(done) {
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var promise = new Promise(function(resolve, reject) {
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reject(1)
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resolve(2)
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callAsync(function() {resolve(3)})
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})
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("rejects asynchronously", function(done) {
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var state = 0
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var promise = Promise.reject()
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state = 1
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promise.then(null, function(value) {
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o(state).equals(2)
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done()
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})
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state = 2
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})
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o("does not catch itself", function(done) {
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var callCount = 0
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var promise = Promise.resolve().then(function() {throw 1}, function() {callCount++})
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promise.then(null, function() {
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o(callCount).equals(0)
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done()
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})
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})
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o("rejects via static method", function(done) {
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var promise = Promise.reject(1)
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promise.then(null, function(value) {
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o(value).equals(1)
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return value
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}).then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("rejects synchronously via executor", function(done) {
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var promise = new Promise(function(resolve, reject) {
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reject(1)
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})
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("rejects asynchronously via executor", function(done) {
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var promise = new Promise(function(resolve, reject) {
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callAsync(function() {reject(1)})
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})
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("rejects via executor on error", function(done) {
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var promise = new Promise(function(resolve, reject) {
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throw 1
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})
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("rejects on fulfillment error", function(done) {
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var promise = Promise.resolve()
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promise.then(function() {
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throw 1
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}).then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("rejects on rejection error", function(done) {
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var promise = Promise.resolve()
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promise.then(function() {
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throw 1
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}).then(null, function() {
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throw 2
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}).then(null, function(value) {
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o(value).equals(2)
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done()
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})
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})
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})
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o.spec("promise absorption", function() {
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o("absorbs resolved promise via static resolver", function(done) {
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var promise = Promise.resolve(Promise.resolve(1))
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promise.then(function(value) {
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o(value).equals(1)
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}).then(done)
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})
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o("absorbs resolved promise in executor resolve", function(done) {
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var promise = new Promise(function(resolve, reject) {
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resolve(Promise.resolve(1))
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})
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promise.then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs resolved promise on fulfillment", function(done) {
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var promise = Promise.resolve()
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promise.then(function() {
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return Promise.resolve(1)
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}).then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs rejected promise via static resolver", function(done) {
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var promise = Promise.resolve(Promise.reject(1))
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs rejected promise in executor resolve", function(done) {
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var promise = new Promise(function(resolve, reject) {
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resolve(Promise.reject(1))
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})
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs rejected promise on fulfillment", function(done) {
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var promise = Promise.resolve()
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promise.then(function() {
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return Promise.reject(1)
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}).then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs pending promise that resolves via static resolver", function(done) {
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var pending = new Promise(function(resolve, reject) {
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setTimeout(function() {resolve(1)}, 10)
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})
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var promise = Promise.resolve(pending)
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promise.then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs pending promise that resolves in executor resolve", function(done) {
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var pending = new Promise(function(resolve, reject) {
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setTimeout(function() {resolve(1)}, 10)
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})
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var promise = new Promise(function(resolve, reject) {
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resolve(pending)
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})
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promise.then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs pending promise that resolves on fulfillment", function(done) {
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var pending = new Promise(function(resolve, reject) {
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setTimeout(function() {resolve(1)}, 10)
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})
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var promise = Promise.resolve()
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promise.then(function() {
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return pending
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}).then(function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs pending promise that rejects via static resolver", function(done) {
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var pending = new Promise(function(resolve, reject) {
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setTimeout(function() {reject(1)}, 10)
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})
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var promise = Promise.resolve(pending)
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs pending promise that rejects in executor resolve", function(done) {
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var pending = new Promise(function(resolve, reject) {
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setTimeout(function() {reject(1)}, 10)
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})
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var promise = new Promise(function(resolve, reject) {
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resolve(pending)
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})
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promise.then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("absorbs pending promise that rejects on fulfillment", function(done) {
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var pending = new Promise(function(resolve, reject) {
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setTimeout(function() {reject(1)}, 10)
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})
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var promise = Promise.resolve()
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promise.then(function() {
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return pending
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}).then(null, function(value) {
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o(value).equals(1)
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done()
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})
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})
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o("does not absorb resolved promise via static rejector", function(done) {
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var promise = Promise.reject(Promise.resolve(1))
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promise.then(null, function(value) {
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o(value instanceof Promise).equals(true)
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done()
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})
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})
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o("does not absorb rejected promise via static rejector", function(done) {
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var rejected = Promise.reject(1)
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rejected.catch(function() {})
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var promise = Promise.reject(rejected)
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promise.then(null, function(value) {
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o(value instanceof Promise).equals(true)
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done()
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})
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})
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o("does not absorb resolved promise in executor reject", function(done) {
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var promise = new Promise(function(resolve, reject) {
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reject(Promise.resolve(1))
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})
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promise.then(null, function(value) {
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o(value instanceof Promise).equals(true)
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done()
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})
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})
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o("does not absorb rejected promise in executor reject", function(done) {
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var promise = new Promise(function(resolve, reject) {
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var rejected = Promise.reject(1)
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rejected.catch(function() {})
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reject(rejected)
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})
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promise.then(null, function(value) {
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o(value instanceof Promise).equals(true)
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done()
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})
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})
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o("does not absorb resolved promise on fulfillment error", function(done) {
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var promise = Promise.resolve()
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promise.then(function() {
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throw Promise.resolve(1)
|
||||
}).then(null, function(value) {
|
||||
o(value instanceof Promise).equals(true)
|
||||
done()
|
||||
})
|
||||
})
|
||||
o("does not absorb rejected promise on fulfillment error", function(done) {
|
||||
var promise = Promise.resolve()
|
||||
|
||||
promise.then(function() {
|
||||
var rejected = Promise.reject(1)
|
||||
rejected.catch(function() {})
|
||||
throw rejected
|
||||
}).then(null, function(value) {
|
||||
o(value instanceof Promise).equals(true)
|
||||
done()
|
||||
})
|
||||
})
|
||||
})
|
||||
o.spec("race", function() {
|
||||
o("resolves to first resolved", function(done) {
|
||||
var a = Promise.resolve(1)
|
||||
var b = new Promise(function(resolve, reject) {
|
||||
callAsync(function() {resolve(2)})
|
||||
})
|
||||
Promise.race([a, b]).then(function(value) {
|
||||
o(value).equals(1)
|
||||
done()
|
||||
})
|
||||
})
|
||||
o("rejects to first rejected", function(done) {
|
||||
var a = Promise.reject(1)
|
||||
var b = new Promise(function(resolve, reject) {
|
||||
callAsync(function() {reject(2)})
|
||||
})
|
||||
Promise.race([a, b]).then(null, function(value) {
|
||||
o(value).equals(1)
|
||||
done()
|
||||
})
|
||||
})
|
||||
})
|
||||
o.spec("all", function() {
|
||||
o("resolves to array", function(done) {
|
||||
var a = new Promise(function(resolve, reject) {
|
||||
callAsync(function() {resolve(1)})
|
||||
})
|
||||
var b = Promise.resolve(2)
|
||||
Promise.all([a, b]).then(function(value) {
|
||||
o(value).deepEquals([1, 2])
|
||||
done()
|
||||
})
|
||||
})
|
||||
o("resolves non-promise to itself", function(done) {
|
||||
var a = new Promise(function(resolve, reject) {
|
||||
callAsync(function() {resolve(1)})
|
||||
})
|
||||
var b = Promise.resolve(2)
|
||||
var c = 3
|
||||
Promise.all([a, b, c]).then(function(value) {
|
||||
o(value).deepEquals([1, 2, 3])
|
||||
done()
|
||||
})
|
||||
})
|
||||
o("rejects to first rejected", function(done) {
|
||||
var a = Promise.reject(1)
|
||||
var b = new Promise(function(resolve, reject) {
|
||||
callAsync(function() {reject(2)})
|
||||
})
|
||||
Promise.all([a, b]).then(null, function(value) {
|
||||
o(value).equals(1)
|
||||
done()
|
||||
})
|
||||
})
|
||||
})
|
||||
})
|
||||
Loading…
Add table
Add a link
Reference in a new issue