blob: 4b11449b8669c2d916f4ef34b94ca10825119c53 [file] [log] [blame]
'use strict';
var immediate = require('immediate');
/* istanbul ignore next */
function INTERNAL() {}
var handlers = {};
var REJECTED = ['REJECTED'];
var FULFILLED = ['FULFILLED'];
var PENDING = ['PENDING'];
/* istanbul ignore else */
if (!process.browser) {
// in which we actually take advantage of JS scoping
var UNHANDLED = ['UNHANDLED'];
}
module.exports = Promise;
function Promise(resolver) {
if (typeof resolver !== 'function') {
throw new TypeError('resolver must be a function');
}
this.state = PENDING;
this.queue = [];
this.outcome = void 0;
/* istanbul ignore else */
if (!process.browser) {
this.handled = UNHANDLED;
}
if (resolver !== INTERNAL) {
safelyResolveThenable(this, resolver);
}
}
Promise.prototype.catch = function (onRejected) {
return this.then(null, onRejected);
};
Promise.prototype.then = function (onFulfilled, onRejected) {
if (typeof onFulfilled !== 'function' && this.state === FULFILLED ||
typeof onRejected !== 'function' && this.state === REJECTED) {
return this;
}
var promise = new this.constructor(INTERNAL);
/* istanbul ignore else */
if (!process.browser) {
if (this.handled === UNHANDLED) {
this.handled = null;
}
}
if (this.state !== PENDING) {
var resolver = this.state === FULFILLED ? onFulfilled : onRejected;
unwrap(promise, resolver, this.outcome);
} else {
this.queue.push(new QueueItem(promise, onFulfilled, onRejected));
}
return promise;
};
function QueueItem(promise, onFulfilled, onRejected) {
this.promise = promise;
if (typeof onFulfilled === 'function') {
this.onFulfilled = onFulfilled;
this.callFulfilled = this.otherCallFulfilled;
}
if (typeof onRejected === 'function') {
this.onRejected = onRejected;
this.callRejected = this.otherCallRejected;
}
}
QueueItem.prototype.callFulfilled = function (value) {
handlers.resolve(this.promise, value);
};
QueueItem.prototype.otherCallFulfilled = function (value) {
unwrap(this.promise, this.onFulfilled, value);
};
QueueItem.prototype.callRejected = function (value) {
handlers.reject(this.promise, value);
};
QueueItem.prototype.otherCallRejected = function (value) {
unwrap(this.promise, this.onRejected, value);
};
function unwrap(promise, func, value) {
immediate(function () {
var returnValue;
try {
returnValue = func(value);
} catch (e) {
return handlers.reject(promise, e);
}
if (returnValue === promise) {
handlers.reject(promise, new TypeError('Cannot resolve promise with itself'));
} else {
handlers.resolve(promise, returnValue);
}
});
}
handlers.resolve = function (self, value) {
var result = tryCatch(getThen, value);
if (result.status === 'error') {
return handlers.reject(self, result.value);
}
var thenable = result.value;
if (thenable) {
safelyResolveThenable(self, thenable);
} else {
self.state = FULFILLED;
self.outcome = value;
var i = -1;
var len = self.queue.length;
while (++i < len) {
self.queue[i].callFulfilled(value);
}
}
return self;
};
handlers.reject = function (self, error) {
self.state = REJECTED;
self.outcome = error;
/* istanbul ignore else */
if (!process.browser) {
if (self.handled === UNHANDLED) {
immediate(function () {
if (self.handled === UNHANDLED) {
process.emit('unhandledRejection', error, self);
}
});
}
}
var i = -1;
var len = self.queue.length;
while (++i < len) {
self.queue[i].callRejected(error);
}
return self;
};
function getThen(obj) {
// Make sure we only access the accessor once as required by the spec
var then = obj && obj.then;
if (obj && (typeof obj === 'object' || typeof obj === 'function') && typeof then === 'function') {
return function appyThen() {
then.apply(obj, arguments);
};
}
}
function safelyResolveThenable(self, thenable) {
// Either fulfill, reject or reject with error
var called = false;
function onError(value) {
if (called) {
return;
}
called = true;
handlers.reject(self, value);
}
function onSuccess(value) {
if (called) {
return;
}
called = true;
handlers.resolve(self, value);
}
function tryToUnwrap() {
thenable(onSuccess, onError);
}
var result = tryCatch(tryToUnwrap);
if (result.status === 'error') {
onError(result.value);
}
}
function tryCatch(func, value) {
var out = {};
try {
out.value = func(value);
out.status = 'success';
} catch (e) {
out.status = 'error';
out.value = e;
}
return out;
}
Promise.resolve = resolve;
function resolve(value) {
if (value instanceof this) {
return value;
}
return handlers.resolve(new this(INTERNAL), value);
}
Promise.reject = reject;
function reject(reason) {
var promise = new this(INTERNAL);
return handlers.reject(promise, reason);
}
Promise.all = all;
function all(iterable) {
var self = this;
if (Object.prototype.toString.call(iterable) !== '[object Array]') {
return this.reject(new TypeError('must be an array'));
}
var len = iterable.length;
var called = false;
if (!len) {
return this.resolve([]);
}
var values = new Array(len);
var resolved = 0;
var i = -1;
var promise = new this(INTERNAL);
while (++i < len) {
allResolver(iterable[i], i);
}
return promise;
function allResolver(value, i) {
self.resolve(value).then(resolveFromAll, function (error) {
if (!called) {
called = true;
handlers.reject(promise, error);
}
});
function resolveFromAll(outValue) {
values[i] = outValue;
if (++resolved === len && !called) {
called = true;
handlers.resolve(promise, values);
}
}
}
}
Promise.race = race;
function race(iterable) {
var self = this;
if (Object.prototype.toString.call(iterable) !== '[object Array]') {
return this.reject(new TypeError('must be an array'));
}
var len = iterable.length;
var called = false;
if (!len) {
return this.resolve([]);
}
var i = -1;
var promise = new this(INTERNAL);
while (++i < len) {
resolver(iterable[i]);
}
return promise;
function resolver(value) {
self.resolve(value).then(function (response) {
if (!called) {
called = true;
handlers.resolve(promise, response);
}
}, function (error) {
if (!called) {
called = true;
handlers.reject(promise, error);
}
});
}
}