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promise bug fixes (work in progress)

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This commit is contained in:
Leo Horie 2016-05-28 01:12:20 -04:00
parent 3c9ec0d2d6
commit 3bb0a6287f
2 changed files with 132 additions and 20 deletions
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58
promise/promise.js
View file

@ -1,39 +1,55 @@
"use strict"
{
function Promise(executor) {
if (!(this instanceof Promise)) throw new Error("Promise must be called with `new`")
if (typeof executor !== "function") throw new Error("executor must be a function")
var self = this, resolvers = [], rejectors = [], resolveCurrent = handler(resolvers, true), rejectCurrent = handler(rejectors, false)
function handler(list, shouldAbsorb) {
var done = false
return function execute(value) {
if (shouldAbsorb && (typeof value === "object" || typeof value === "function") && typeof value.then === "function") {
if (value === self) rejectCurrent(new Error("Promise cannot be resolved with itself"))
value.then(execute, rejectCurrent)
if (done) return
done = true
var then
try {
if (shouldAbsorb && value != null && (typeof value === "object" || typeof value === "function") && typeof (then = value.then) === "function") {
if (value === self) rejectCurrent(new TypeError("Promise can't be resolved w/ itself"))
then.call(value, handler(list, shouldAbsorb), rejectCurrent)
}
else {
setTimeout(function() {
for (var i = 0; i < list.length; i++) list[i](value)
instance.retry = function() {
done = false
execute(value)
}
}, 0)
}
}
else {
setTimeout(function() {
for (var i = 0; i < list.length; i++) list[i](value)
resolvers.length = 0, rejectors.length = 0
}, 0)
catch (e) {
rejectCurrent(e)
}
}
}
var instance = this._instance = {resolvers: resolvers, rejectors: rejectors}
this._instance = {resolvers: resolvers, rejectors: rejectors}
try {executor(resolveCurrent, rejectCurrent)} catch (e) {rejectCurrent(e)}
}
Promise.prototype.then = function(onFulfilled, onRejection) {
function handle(callback, list) {
if (typeof callback === "function") {
list.push(function(value) {
try {resolveNext(callback(value))} catch (e) {if (rejectNext) rejectNext(e)}
})
}
var self = this
function handle(callback, list, next, state) {
list.push(function(value) {
if (typeof callback !== "function") next(value)
try {resolveNext(callback(value))} catch (e) {if (rejectNext) rejectNext(e)}
})
var retry = self._instance.retry
if (retry) retry()
}
var resolveNext, rejectNext
handle(onFulfilled, this._instance.resolvers), handle(onRejection, this._instance.rejectors)
return new Promise(function(resolve, reject) {resolveNext = resolve, rejectNext = reject})
var promise = new Promise(function(resolve, reject) {resolveNext = resolve, rejectNext = reject})
handle(onFulfilled, this._instance.resolvers, resolveNext, true), handle(onRejection, this._instance.rejectors, rejectNext, false)
return promise
}
Promise.prototype.catch = function(onRejection) {
return this.then(null, onRejection)
@ -55,8 +71,9 @@ Promise.all = function(list) {
values[i] = value
if (count === total) resolve(values)
}
if ((typeof list[i] === "object" || typeof list[i] === "function") && typeof list[i].then === "function") {
list[i].then(consume, reject)
var then
if (list[i] != null && (typeof list[i] === "object" || typeof list[i] === "function") && typeof (then = list[i].then) === "function") {
then.call(list[i], consume, reject)
}
else consume(list[i])
}(i)
@ -72,3 +89,4 @@ Promise.race = function(list) {
}
module.exports = Promise
}

94
promise/tests/test-promise.js
View file

@ -133,6 +133,22 @@ o.spec("promise", function() {
promise.then(null, done)
})
o("non-function onFulfilled is ignored", function(done) {
var promise = Promise.resolve(1)
promise.then(null, null).then(function(value) {
o(value).equals(1)
done()
})
})
o("non-function onFulfilled is ignored", function(done) {
var promise = Promise.resolve(1)
promise.then(null).then(function(value) {
o(value).equals(1)
done()
})
})
})
o.spec("reject", function() {
o("rejects once", function(done) {
@ -247,6 +263,14 @@ o.spec("promise", function() {
done()
})
})
o("non-function onRejected is ignored", function(done) {
var promise = Promise.reject(1)
promise.then(function() {}, null).then(null, function(value) {
o(value).equals(1)
done()
})
})
})
o.spec("promise absorption", function() {
o("absorbs resolved promise via static resolver", function(done) {
@ -440,6 +464,37 @@ o.spec("promise", function() {
done()
})
})
o("promise stays pending if absorbed promise is pending", function(done) {
var promise = new Promise(function(resolve) {resolve()})
var fulfilled = false, rejected = false
promise.then(function() {
return new Promise(function() {})
}).then(function() {
fulfilled = true
}, function() {
rejected = false
})
setTimeout(function() {
o(fulfilled).equals(false)
o(rejected).equals(false)
done()
}, 10)
})
o("absorbs early resolved promise", function(done, t) {
var resolved = Promise.resolve(1)
var promise = new Promise(function(resolve) {
setTimeout(function() {
resolve(resolved)
}, 10)
})
promise.then(function(value) {
o(value).equals(1)
done()
})
})
})
o.spec("race", function() {
o("resolves to first resolved", function(done) {
@ -496,4 +551,43 @@ o.spec("promise", function() {
})
})
})
o.spec("A+ compliance", function() {
o("accesses then only once", function(done) {
var readCount = 0
var promise = Promise.resolve(1).then(function() {
return Object.create(null, {
then: {
get: function () {
++readCount
return function(onFulfilled) {
onFulfilled()
}
}
}
})
})
promise.then(function(value) {
o(readCount).equals(1)
done()
})
})
o("works if thennable resolves twice", function(done) {
var promise = Promise.resolve({
then: function(res) {
res({
then: function(resolve) {
setTimeout(function() {resolve(2)})
}
})
res(1)
}
})
promise.then(function(value) {
o(value).equals(2)
done()
})
})
})
})