You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
966 lines
28 KiB
966 lines
28 KiB
/*!
|
|
* @overview es6-promise - a tiny implementation of Promises/A+.
|
|
* @copyright Copyright (c) 2014 Yehuda Katz, Tom Dale, Stefan Penner and contributors (Conversion to ES6 API by Jake Archibald)
|
|
* @license Licensed under MIT license
|
|
* See https://raw.githubusercontent.com/jakearchibald/es6-promise/master/LICENSE
|
|
* @version 2.0.0
|
|
*/
|
|
|
|
(function() {
|
|
"use strict";
|
|
|
|
function $$utils$$objectOrFunction(x) {
|
|
return typeof x === 'function' || (typeof x === 'object' && x !== null);
|
|
}
|
|
|
|
function $$utils$$isFunction(x) {
|
|
return typeof x === 'function';
|
|
}
|
|
|
|
function $$utils$$isMaybeThenable(x) {
|
|
return typeof x === 'object' && x !== null;
|
|
}
|
|
|
|
var $$utils$$_isArray;
|
|
|
|
if (!Array.isArray) {
|
|
$$utils$$_isArray = function (x) {
|
|
return Object.prototype.toString.call(x) === '[object Array]';
|
|
};
|
|
} else {
|
|
$$utils$$_isArray = Array.isArray;
|
|
}
|
|
|
|
var $$utils$$isArray = $$utils$$_isArray;
|
|
var $$utils$$now = Date.now || function() { return new Date().getTime(); };
|
|
function $$utils$$F() { }
|
|
|
|
var $$utils$$o_create = (Object.create || function (o) {
|
|
if (arguments.length > 1) {
|
|
throw new Error('Second argument not supported');
|
|
}
|
|
if (typeof o !== 'object') {
|
|
throw new TypeError('Argument must be an object');
|
|
}
|
|
$$utils$$F.prototype = o;
|
|
return new $$utils$$F();
|
|
});
|
|
|
|
var $$asap$$len = 0;
|
|
|
|
var $$asap$$default = function asap(callback, arg) {
|
|
$$asap$$queue[$$asap$$len] = callback;
|
|
$$asap$$queue[$$asap$$len + 1] = arg;
|
|
$$asap$$len += 2;
|
|
if ($$asap$$len === 2) {
|
|
// If len is 1, that means that we need to schedule an async flush.
|
|
// If additional callbacks are queued before the queue is flushed, they
|
|
// will be processed by this flush that we are scheduling.
|
|
$$asap$$scheduleFlush();
|
|
}
|
|
};
|
|
|
|
var $$asap$$browserGlobal = (typeof window !== 'undefined') ? window : {};
|
|
var $$asap$$BrowserMutationObserver = $$asap$$browserGlobal.MutationObserver || $$asap$$browserGlobal.WebKitMutationObserver;
|
|
|
|
// test for web worker but not in IE10
|
|
var $$asap$$isWorker = typeof Uint8ClampedArray !== 'undefined' &&
|
|
typeof importScripts !== 'undefined' &&
|
|
typeof MessageChannel !== 'undefined';
|
|
|
|
// node
|
|
function $$asap$$useNextTick() {
|
|
return function() {
|
|
process.nextTick($$asap$$flush);
|
|
};
|
|
}
|
|
|
|
function $$asap$$useMutationObserver() {
|
|
var iterations = 0;
|
|
var observer = new $$asap$$BrowserMutationObserver($$asap$$flush);
|
|
var node = document.createTextNode('');
|
|
observer.observe(node, { characterData: true });
|
|
|
|
return function() {
|
|
node.data = (iterations = ++iterations % 2);
|
|
};
|
|
}
|
|
|
|
// web worker
|
|
function $$asap$$useMessageChannel() {
|
|
var channel = new MessageChannel();
|
|
channel.port1.onmessage = $$asap$$flush;
|
|
return function () {
|
|
channel.port2.postMessage(0);
|
|
};
|
|
}
|
|
|
|
function $$asap$$useSetTimeout() {
|
|
return function() {
|
|
setTimeout($$asap$$flush, 1);
|
|
};
|
|
}
|
|
|
|
var $$asap$$queue = new Array(1000);
|
|
|
|
function $$asap$$flush() {
|
|
for (var i = 0; i < $$asap$$len; i+=2) {
|
|
var callback = $$asap$$queue[i];
|
|
var arg = $$asap$$queue[i+1];
|
|
|
|
callback(arg);
|
|
|
|
$$asap$$queue[i] = undefined;
|
|
$$asap$$queue[i+1] = undefined;
|
|
}
|
|
|
|
$$asap$$len = 0;
|
|
}
|
|
|
|
var $$asap$$scheduleFlush;
|
|
|
|
// Decide what async method to use to triggering processing of queued callbacks:
|
|
if (typeof process !== 'undefined' && {}.toString.call(process) === '[object process]') {
|
|
$$asap$$scheduleFlush = $$asap$$useNextTick();
|
|
} else if ($$asap$$BrowserMutationObserver) {
|
|
$$asap$$scheduleFlush = $$asap$$useMutationObserver();
|
|
} else if ($$asap$$isWorker) {
|
|
$$asap$$scheduleFlush = $$asap$$useMessageChannel();
|
|
} else {
|
|
$$asap$$scheduleFlush = $$asap$$useSetTimeout();
|
|
}
|
|
|
|
function $$$internal$$noop() {}
|
|
var $$$internal$$PENDING = void 0;
|
|
var $$$internal$$FULFILLED = 1;
|
|
var $$$internal$$REJECTED = 2;
|
|
var $$$internal$$GET_THEN_ERROR = new $$$internal$$ErrorObject();
|
|
|
|
function $$$internal$$selfFullfillment() {
|
|
return new TypeError("You cannot resolve a promise with itself");
|
|
}
|
|
|
|
function $$$internal$$cannotReturnOwn() {
|
|
return new TypeError('A promises callback cannot return that same promise.')
|
|
}
|
|
|
|
function $$$internal$$getThen(promise) {
|
|
try {
|
|
return promise.then;
|
|
} catch(error) {
|
|
$$$internal$$GET_THEN_ERROR.error = error;
|
|
return $$$internal$$GET_THEN_ERROR;
|
|
}
|
|
}
|
|
|
|
function $$$internal$$tryThen(then, value, fulfillmentHandler, rejectionHandler) {
|
|
try {
|
|
then.call(value, fulfillmentHandler, rejectionHandler);
|
|
} catch(e) {
|
|
return e;
|
|
}
|
|
}
|
|
|
|
function $$$internal$$handleForeignThenable(promise, thenable, then) {
|
|
$$asap$$default(function(promise) {
|
|
var sealed = false;
|
|
var error = $$$internal$$tryThen(then, thenable, function(value) {
|
|
if (sealed) { return; }
|
|
sealed = true;
|
|
if (thenable !== value) {
|
|
$$$internal$$resolve(promise, value);
|
|
} else {
|
|
$$$internal$$fulfill(promise, value);
|
|
}
|
|
}, function(reason) {
|
|
if (sealed) { return; }
|
|
sealed = true;
|
|
|
|
$$$internal$$reject(promise, reason);
|
|
}, 'Settle: ' + (promise._label || ' unknown promise'));
|
|
|
|
if (!sealed && error) {
|
|
sealed = true;
|
|
$$$internal$$reject(promise, error);
|
|
}
|
|
}, promise);
|
|
}
|
|
|
|
function $$$internal$$handleOwnThenable(promise, thenable) {
|
|
if (thenable._state === $$$internal$$FULFILLED) {
|
|
$$$internal$$fulfill(promise, thenable._result);
|
|
} else if (promise._state === $$$internal$$REJECTED) {
|
|
$$$internal$$reject(promise, thenable._result);
|
|
} else {
|
|
$$$internal$$subscribe(thenable, undefined, function(value) {
|
|
$$$internal$$resolve(promise, value);
|
|
}, function(reason) {
|
|
$$$internal$$reject(promise, reason);
|
|
});
|
|
}
|
|
}
|
|
|
|
function $$$internal$$handleMaybeThenable(promise, maybeThenable) {
|
|
if (maybeThenable.constructor === promise.constructor) {
|
|
$$$internal$$handleOwnThenable(promise, maybeThenable);
|
|
} else {
|
|
var then = $$$internal$$getThen(maybeThenable);
|
|
|
|
if (then === $$$internal$$GET_THEN_ERROR) {
|
|
$$$internal$$reject(promise, $$$internal$$GET_THEN_ERROR.error);
|
|
} else if (then === undefined) {
|
|
$$$internal$$fulfill(promise, maybeThenable);
|
|
} else if ($$utils$$isFunction(then)) {
|
|
$$$internal$$handleForeignThenable(promise, maybeThenable, then);
|
|
} else {
|
|
$$$internal$$fulfill(promise, maybeThenable);
|
|
}
|
|
}
|
|
}
|
|
|
|
function $$$internal$$resolve(promise, value) {
|
|
if (promise === value) {
|
|
$$$internal$$reject(promise, $$$internal$$selfFullfillment());
|
|
} else if ($$utils$$objectOrFunction(value)) {
|
|
$$$internal$$handleMaybeThenable(promise, value);
|
|
} else {
|
|
$$$internal$$fulfill(promise, value);
|
|
}
|
|
}
|
|
|
|
function $$$internal$$publishRejection(promise) {
|
|
if (promise._onerror) {
|
|
promise._onerror(promise._result);
|
|
}
|
|
|
|
$$$internal$$publish(promise);
|
|
}
|
|
|
|
function $$$internal$$fulfill(promise, value) {
|
|
if (promise._state !== $$$internal$$PENDING) { return; }
|
|
|
|
promise._result = value;
|
|
promise._state = $$$internal$$FULFILLED;
|
|
|
|
if (promise._subscribers.length === 0) {
|
|
} else {
|
|
$$asap$$default($$$internal$$publish, promise);
|
|
}
|
|
}
|
|
|
|
function $$$internal$$reject(promise, reason) {
|
|
if (promise._state !== $$$internal$$PENDING) { return; }
|
|
promise._state = $$$internal$$REJECTED;
|
|
promise._result = reason;
|
|
|
|
$$asap$$default($$$internal$$publishRejection, promise);
|
|
}
|
|
|
|
function $$$internal$$subscribe(parent, child, onFulfillment, onRejection) {
|
|
var subscribers = parent._subscribers;
|
|
var length = subscribers.length;
|
|
|
|
parent._onerror = null;
|
|
|
|
subscribers[length] = child;
|
|
subscribers[length + $$$internal$$FULFILLED] = onFulfillment;
|
|
subscribers[length + $$$internal$$REJECTED] = onRejection;
|
|
|
|
if (length === 0 && parent._state) {
|
|
$$asap$$default($$$internal$$publish, parent);
|
|
}
|
|
}
|
|
|
|
function $$$internal$$publish(promise) {
|
|
var subscribers = promise._subscribers;
|
|
var settled = promise._state;
|
|
|
|
if (subscribers.length === 0) { return; }
|
|
|
|
var child, callback, detail = promise._result;
|
|
|
|
for (var i = 0; i < subscribers.length; i += 3) {
|
|
child = subscribers[i];
|
|
callback = subscribers[i + settled];
|
|
|
|
if (child) {
|
|
$$$internal$$invokeCallback(settled, child, callback, detail);
|
|
} else {
|
|
callback(detail);
|
|
}
|
|
}
|
|
|
|
promise._subscribers.length = 0;
|
|
}
|
|
|
|
function $$$internal$$ErrorObject() {
|
|
this.error = null;
|
|
}
|
|
|
|
var $$$internal$$TRY_CATCH_ERROR = new $$$internal$$ErrorObject();
|
|
|
|
function $$$internal$$tryCatch(callback, detail) {
|
|
try {
|
|
return callback(detail);
|
|
} catch(e) {
|
|
$$$internal$$TRY_CATCH_ERROR.error = e;
|
|
return $$$internal$$TRY_CATCH_ERROR;
|
|
}
|
|
}
|
|
|
|
function $$$internal$$invokeCallback(settled, promise, callback, detail) {
|
|
var hasCallback = $$utils$$isFunction(callback),
|
|
value, error, succeeded, failed;
|
|
|
|
if (hasCallback) {
|
|
value = $$$internal$$tryCatch(callback, detail);
|
|
|
|
if (value === $$$internal$$TRY_CATCH_ERROR) {
|
|
failed = true;
|
|
error = value.error;
|
|
value = null;
|
|
} else {
|
|
succeeded = true;
|
|
}
|
|
|
|
if (promise === value) {
|
|
$$$internal$$reject(promise, $$$internal$$cannotReturnOwn());
|
|
return;
|
|
}
|
|
|
|
} else {
|
|
value = detail;
|
|
succeeded = true;
|
|
}
|
|
|
|
if (promise._state !== $$$internal$$PENDING) {
|
|
// noop
|
|
} else if (hasCallback && succeeded) {
|
|
$$$internal$$resolve(promise, value);
|
|
} else if (failed) {
|
|
$$$internal$$reject(promise, error);
|
|
} else if (settled === $$$internal$$FULFILLED) {
|
|
$$$internal$$fulfill(promise, value);
|
|
} else if (settled === $$$internal$$REJECTED) {
|
|
$$$internal$$reject(promise, value);
|
|
}
|
|
}
|
|
|
|
function $$$internal$$initializePromise(promise, resolver) {
|
|
try {
|
|
resolver(function resolvePromise(value){
|
|
$$$internal$$resolve(promise, value);
|
|
}, function rejectPromise(reason) {
|
|
$$$internal$$reject(promise, reason);
|
|
});
|
|
} catch(e) {
|
|
$$$internal$$reject(promise, e);
|
|
}
|
|
}
|
|
|
|
function $$$enumerator$$makeSettledResult(state, position, value) {
|
|
if (state === $$$internal$$FULFILLED) {
|
|
return {
|
|
state: 'fulfilled',
|
|
value: value
|
|
};
|
|
} else {
|
|
return {
|
|
state: 'rejected',
|
|
reason: value
|
|
};
|
|
}
|
|
}
|
|
|
|
function $$$enumerator$$Enumerator(Constructor, input, abortOnReject, label) {
|
|
this._instanceConstructor = Constructor;
|
|
this.promise = new Constructor($$$internal$$noop, label);
|
|
this._abortOnReject = abortOnReject;
|
|
|
|
if (this._validateInput(input)) {
|
|
this._input = input;
|
|
this.length = input.length;
|
|
this._remaining = input.length;
|
|
|
|
this._init();
|
|
|
|
if (this.length === 0) {
|
|
$$$internal$$fulfill(this.promise, this._result);
|
|
} else {
|
|
this.length = this.length || 0;
|
|
this._enumerate();
|
|
if (this._remaining === 0) {
|
|
$$$internal$$fulfill(this.promise, this._result);
|
|
}
|
|
}
|
|
} else {
|
|
$$$internal$$reject(this.promise, this._validationError());
|
|
}
|
|
}
|
|
|
|
$$$enumerator$$Enumerator.prototype._validateInput = function(input) {
|
|
return $$utils$$isArray(input);
|
|
};
|
|
|
|
$$$enumerator$$Enumerator.prototype._validationError = function() {
|
|
return new Error('Array Methods must be provided an Array');
|
|
};
|
|
|
|
$$$enumerator$$Enumerator.prototype._init = function() {
|
|
this._result = new Array(this.length);
|
|
};
|
|
|
|
var $$$enumerator$$default = $$$enumerator$$Enumerator;
|
|
|
|
$$$enumerator$$Enumerator.prototype._enumerate = function() {
|
|
var length = this.length;
|
|
var promise = this.promise;
|
|
var input = this._input;
|
|
|
|
for (var i = 0; promise._state === $$$internal$$PENDING && i < length; i++) {
|
|
this._eachEntry(input[i], i);
|
|
}
|
|
};
|
|
|
|
$$$enumerator$$Enumerator.prototype._eachEntry = function(entry, i) {
|
|
var c = this._instanceConstructor;
|
|
if ($$utils$$isMaybeThenable(entry)) {
|
|
if (entry.constructor === c && entry._state !== $$$internal$$PENDING) {
|
|
entry._onerror = null;
|
|
this._settledAt(entry._state, i, entry._result);
|
|
} else {
|
|
this._willSettleAt(c.resolve(entry), i);
|
|
}
|
|
} else {
|
|
this._remaining--;
|
|
this._result[i] = this._makeResult($$$internal$$FULFILLED, i, entry);
|
|
}
|
|
};
|
|
|
|
$$$enumerator$$Enumerator.prototype._settledAt = function(state, i, value) {
|
|
var promise = this.promise;
|
|
|
|
if (promise._state === $$$internal$$PENDING) {
|
|
this._remaining--;
|
|
|
|
if (this._abortOnReject && state === $$$internal$$REJECTED) {
|
|
$$$internal$$reject(promise, value);
|
|
} else {
|
|
this._result[i] = this._makeResult(state, i, value);
|
|
}
|
|
}
|
|
|
|
if (this._remaining === 0) {
|
|
$$$internal$$fulfill(promise, this._result);
|
|
}
|
|
};
|
|
|
|
$$$enumerator$$Enumerator.prototype._makeResult = function(state, i, value) {
|
|
return value;
|
|
};
|
|
|
|
$$$enumerator$$Enumerator.prototype._willSettleAt = function(promise, i) {
|
|
var enumerator = this;
|
|
|
|
$$$internal$$subscribe(promise, undefined, function(value) {
|
|
enumerator._settledAt($$$internal$$FULFILLED, i, value);
|
|
}, function(reason) {
|
|
enumerator._settledAt($$$internal$$REJECTED, i, reason);
|
|
});
|
|
};
|
|
|
|
var $$promise$all$$default = function all(entries, label) {
|
|
return new $$$enumerator$$default(this, entries, true /* abort on reject */, label).promise;
|
|
};
|
|
|
|
var $$promise$race$$default = function race(entries, label) {
|
|
/*jshint validthis:true */
|
|
var Constructor = this;
|
|
|
|
var promise = new Constructor($$$internal$$noop, label);
|
|
|
|
if (!$$utils$$isArray(entries)) {
|
|
$$$internal$$reject(promise, new TypeError('You must pass an array to race.'));
|
|
return promise;
|
|
}
|
|
|
|
var length = entries.length;
|
|
|
|
function onFulfillment(value) {
|
|
$$$internal$$resolve(promise, value);
|
|
}
|
|
|
|
function onRejection(reason) {
|
|
$$$internal$$reject(promise, reason);
|
|
}
|
|
|
|
for (var i = 0; promise._state === $$$internal$$PENDING && i < length; i++) {
|
|
$$$internal$$subscribe(Constructor.resolve(entries[i]), undefined, onFulfillment, onRejection);
|
|
}
|
|
|
|
return promise;
|
|
};
|
|
|
|
var $$promise$resolve$$default = function resolve(object, label) {
|
|
/*jshint validthis:true */
|
|
var Constructor = this;
|
|
|
|
if (object && typeof object === 'object' && object.constructor === Constructor) {
|
|
return object;
|
|
}
|
|
|
|
var promise = new Constructor($$$internal$$noop, label);
|
|
$$$internal$$resolve(promise, object);
|
|
return promise;
|
|
};
|
|
|
|
var $$promise$reject$$default = function reject(reason, label) {
|
|
/*jshint validthis:true */
|
|
var Constructor = this;
|
|
var promise = new Constructor($$$internal$$noop, label);
|
|
$$$internal$$reject(promise, reason);
|
|
return promise;
|
|
};
|
|
|
|
var $$es6$promise$promise$$counter = 0;
|
|
|
|
function $$es6$promise$promise$$needsResolver() {
|
|
throw new TypeError('You must pass a resolver function as the first argument to the promise constructor');
|
|
}
|
|
|
|
function $$es6$promise$promise$$needsNew() {
|
|
throw new TypeError("Failed to construct 'Promise': Please use the 'new' operator, this object constructor cannot be called as a function.");
|
|
}
|
|
|
|
var $$es6$promise$promise$$default = $$es6$promise$promise$$Promise;
|
|
|
|
/**
|
|
Promise objects represent the eventual result of an asynchronous operation. The
|
|
primary way of interacting with a promise is through its `then` method, which
|
|
registers callbacks to receive either a promise’s eventual value or the reason
|
|
why the promise cannot be fulfilled.
|
|
|
|
Terminology
|
|
-----------
|
|
|
|
- `promise` is an object or function with a `then` method whose behavior conforms to this specification.
|
|
- `thenable` is an object or function that defines a `then` method.
|
|
- `value` is any legal JavaScript value (including undefined, a thenable, or a promise).
|
|
- `exception` is a value that is thrown using the throw statement.
|
|
- `reason` is a value that indicates why a promise was rejected.
|
|
- `settled` the final resting state of a promise, fulfilled or rejected.
|
|
|
|
A promise can be in one of three states: pending, fulfilled, or rejected.
|
|
|
|
Promises that are fulfilled have a fulfillment value and are in the fulfilled
|
|
state. Promises that are rejected have a rejection reason and are in the
|
|
rejected state. A fulfillment value is never a thenable.
|
|
|
|
Promises can also be said to *resolve* a value. If this value is also a
|
|
promise, then the original promise's settled state will match the value's
|
|
settled state. So a promise that *resolves* a promise that rejects will
|
|
itself reject, and a promise that *resolves* a promise that fulfills will
|
|
itself fulfill.
|
|
|
|
|
|
Basic Usage:
|
|
------------
|
|
|
|
```js
|
|
var promise = new Promise(function(resolve, reject) {
|
|
// on success
|
|
resolve(value);
|
|
|
|
// on failure
|
|
reject(reason);
|
|
});
|
|
|
|
promise.then(function(value) {
|
|
// on fulfillment
|
|
}, function(reason) {
|
|
// on rejection
|
|
});
|
|
```
|
|
|
|
Advanced Usage:
|
|
---------------
|
|
|
|
Promises shine when abstracting away asynchronous interactions such as
|
|
`XMLHttpRequest`s.
|
|
|
|
```js
|
|
function getJSON(url) {
|
|
return new Promise(function(resolve, reject){
|
|
var xhr = new XMLHttpRequest();
|
|
|
|
xhr.open('GET', url);
|
|
xhr.onreadystatechange = handler;
|
|
xhr.responseType = 'json';
|
|
xhr.setRequestHeader('Accept', 'application/json');
|
|
xhr.send();
|
|
|
|
function handler() {
|
|
if (this.readyState === this.DONE) {
|
|
if (this.status === 200) {
|
|
resolve(this.response);
|
|
} else {
|
|
reject(new Error('getJSON: `' + url + '` failed with status: [' + this.status + ']'));
|
|
}
|
|
}
|
|
};
|
|
});
|
|
}
|
|
|
|
getJSON('/posts.json').then(function(json) {
|
|
// on fulfillment
|
|
}, function(reason) {
|
|
// on rejection
|
|
});
|
|
```
|
|
|
|
Unlike callbacks, promises are great composable primitives.
|
|
|
|
```js
|
|
Promise.all([
|
|
getJSON('/posts'),
|
|
getJSON('/comments')
|
|
]).then(function(values){
|
|
values[0] // => postsJSON
|
|
values[1] // => commentsJSON
|
|
|
|
return values;
|
|
});
|
|
```
|
|
|
|
@class Promise
|
|
@param {function} resolver
|
|
@param {String} label optional string for labeling the promise.
|
|
Useful for tooling.
|
|
@constructor
|
|
*/
|
|
function $$es6$promise$promise$$Promise(resolver, label) {
|
|
this._id = $$es6$promise$promise$$counter++;
|
|
this._label = label;
|
|
this._state = undefined;
|
|
this._result = undefined;
|
|
this._subscribers = [];
|
|
|
|
if ($$$internal$$noop !== resolver) {
|
|
if (!$$utils$$isFunction(resolver)) {
|
|
$$es6$promise$promise$$needsResolver();
|
|
}
|
|
|
|
if (!(this instanceof $$es6$promise$promise$$Promise)) {
|
|
$$es6$promise$promise$$needsNew();
|
|
}
|
|
|
|
$$$internal$$initializePromise(this, resolver);
|
|
}
|
|
}
|
|
|
|
$$es6$promise$promise$$Promise.all = $$promise$all$$default;
|
|
$$es6$promise$promise$$Promise.race = $$promise$race$$default;
|
|
$$es6$promise$promise$$Promise.resolve = $$promise$resolve$$default;
|
|
$$es6$promise$promise$$Promise.reject = $$promise$reject$$default;
|
|
|
|
$$es6$promise$promise$$Promise.prototype = {
|
|
constructor: $$es6$promise$promise$$Promise,
|
|
|
|
/**
|
|
The primary way of interacting with a promise is through its `then` method,
|
|
which registers callbacks to receive either a promise's eventual value or the
|
|
reason why the promise cannot be fulfilled.
|
|
|
|
```js
|
|
findUser().then(function(user){
|
|
// user is available
|
|
}, function(reason){
|
|
// user is unavailable, and you are given the reason why
|
|
});
|
|
```
|
|
|
|
Chaining
|
|
--------
|
|
|
|
The return value of `then` is itself a promise. This second, 'downstream'
|
|
promise is resolved with the return value of the first promise's fulfillment
|
|
or rejection handler, or rejected if the handler throws an exception.
|
|
|
|
```js
|
|
findUser().then(function (user) {
|
|
return user.name;
|
|
}, function (reason) {
|
|
return 'default name';
|
|
}).then(function (userName) {
|
|
// If `findUser` fulfilled, `userName` will be the user's name, otherwise it
|
|
// will be `'default name'`
|
|
});
|
|
|
|
findUser().then(function (user) {
|
|
throw new Error('Found user, but still unhappy');
|
|
}, function (reason) {
|
|
throw new Error('`findUser` rejected and we're unhappy');
|
|
}).then(function (value) {
|
|
// never reached
|
|
}, function (reason) {
|
|
// if `findUser` fulfilled, `reason` will be 'Found user, but still unhappy'.
|
|
// If `findUser` rejected, `reason` will be '`findUser` rejected and we're unhappy'.
|
|
});
|
|
```
|
|
If the downstream promise does not specify a rejection handler, rejection reasons will be propagated further downstream.
|
|
|
|
```js
|
|
findUser().then(function (user) {
|
|
throw new PedagogicalException('Upstream error');
|
|
}).then(function (value) {
|
|
// never reached
|
|
}).then(function (value) {
|
|
// never reached
|
|
}, function (reason) {
|
|
// The `PedgagocialException` is propagated all the way down to here
|
|
});
|
|
```
|
|
|
|
Assimilation
|
|
------------
|
|
|
|
Sometimes the value you want to propagate to a downstream promise can only be
|
|
retrieved asynchronously. This can be achieved by returning a promise in the
|
|
fulfillment or rejection handler. The downstream promise will then be pending
|
|
until the returned promise is settled. This is called *assimilation*.
|
|
|
|
```js
|
|
findUser().then(function (user) {
|
|
return findCommentsByAuthor(user);
|
|
}).then(function (comments) {
|
|
// The user's comments are now available
|
|
});
|
|
```
|
|
|
|
If the assimliated promise rejects, then the downstream promise will also reject.
|
|
|
|
```js
|
|
findUser().then(function (user) {
|
|
return findCommentsByAuthor(user);
|
|
}).then(function (comments) {
|
|
// If `findCommentsByAuthor` fulfills, we'll have the value here
|
|
}, function (reason) {
|
|
// If `findCommentsByAuthor` rejects, we'll have the reason here
|
|
});
|
|
```
|
|
|
|
Simple Example
|
|
--------------
|
|
|
|
Synchronous Example
|
|
|
|
```javascript
|
|
var result;
|
|
|
|
try {
|
|
result = findResult();
|
|
// success
|
|
} catch(reason) {
|
|
// failure
|
|
}
|
|
```
|
|
|
|
Errback Example
|
|
|
|
```js
|
|
findResult(function(result, err){
|
|
if (err) {
|
|
// failure
|
|
} else {
|
|
// success
|
|
}
|
|
});
|
|
```
|
|
|
|
Promise Example;
|
|
|
|
```javascript
|
|
findResult().then(function(result){
|
|
// success
|
|
}, function(reason){
|
|
// failure
|
|
});
|
|
```
|
|
|
|
Advanced Example
|
|
--------------
|
|
|
|
Synchronous Example
|
|
|
|
```javascript
|
|
var author, books;
|
|
|
|
try {
|
|
author = findAuthor();
|
|
books = findBooksByAuthor(author);
|
|
// success
|
|
} catch(reason) {
|
|
// failure
|
|
}
|
|
```
|
|
|
|
Errback Example
|
|
|
|
```js
|
|
|
|
function foundBooks(books) {
|
|
|
|
}
|
|
|
|
function failure(reason) {
|
|
|
|
}
|
|
|
|
findAuthor(function(author, err){
|
|
if (err) {
|
|
failure(err);
|
|
// failure
|
|
} else {
|
|
try {
|
|
findBoooksByAuthor(author, function(books, err) {
|
|
if (err) {
|
|
failure(err);
|
|
} else {
|
|
try {
|
|
foundBooks(books);
|
|
} catch(reason) {
|
|
failure(reason);
|
|
}
|
|
}
|
|
});
|
|
} catch(error) {
|
|
failure(err);
|
|
}
|
|
// success
|
|
}
|
|
});
|
|
```
|
|
|
|
Promise Example;
|
|
|
|
```javascript
|
|
findAuthor().
|
|
then(findBooksByAuthor).
|
|
then(function(books){
|
|
// found books
|
|
}).catch(function(reason){
|
|
// something went wrong
|
|
});
|
|
```
|
|
|
|
@method then
|
|
@param {Function} onFulfilled
|
|
@param {Function} onRejected
|
|
@param {String} label optional string for labeling the promise.
|
|
Useful for tooling.
|
|
@return {Promise}
|
|
*/
|
|
then: function(onFulfillment, onRejection, label) {
|
|
var parent = this;
|
|
var state = parent._state;
|
|
|
|
if (state === $$$internal$$FULFILLED && !onFulfillment || state === $$$internal$$REJECTED && !onRejection) {
|
|
return this;
|
|
}
|
|
|
|
parent._onerror = null;
|
|
|
|
var child = new this.constructor($$$internal$$noop, label);
|
|
var result = parent._result;
|
|
|
|
if (state) {
|
|
var callback = arguments[state - 1];
|
|
$$asap$$default(function(){
|
|
$$$internal$$invokeCallback(state, child, callback, result);
|
|
});
|
|
} else {
|
|
$$$internal$$subscribe(parent, child, onFulfillment, onRejection);
|
|
}
|
|
|
|
return child;
|
|
},
|
|
|
|
/**
|
|
`catch` is simply sugar for `then(undefined, onRejection)` which makes it the same
|
|
as the catch block of a try/catch statement.
|
|
|
|
```js
|
|
function findAuthor(){
|
|
throw new Error('couldn't find that author');
|
|
}
|
|
|
|
// synchronous
|
|
try {
|
|
findAuthor();
|
|
} catch(reason) {
|
|
// something went wrong
|
|
}
|
|
|
|
// async with promises
|
|
findAuthor().catch(function(reason){
|
|
// something went wrong
|
|
});
|
|
```
|
|
|
|
@method catch
|
|
@param {Function} onRejection
|
|
@param {String} label optional string for labeling the promise.
|
|
Useful for tooling.
|
|
@return {Promise}
|
|
*/
|
|
'catch': function(onRejection, label) {
|
|
return this.then(null, onRejection, label);
|
|
}
|
|
};
|
|
|
|
var $$es6$promise$polyfill$$default = function polyfill() {
|
|
var local;
|
|
|
|
if (typeof global !== 'undefined') {
|
|
local = global;
|
|
} else if (typeof window !== 'undefined' && window.document) {
|
|
local = window;
|
|
} else {
|
|
local = self;
|
|
}
|
|
|
|
var es6PromiseSupport =
|
|
"Promise" in local &&
|
|
// Some of these methods are missing from
|
|
// Firefox/Chrome experimental implementations
|
|
"resolve" in local.Promise &&
|
|
"reject" in local.Promise &&
|
|
"all" in local.Promise &&
|
|
"race" in local.Promise &&
|
|
// Older version of the spec had a resolver object
|
|
// as the arg rather than a function
|
|
(function() {
|
|
var resolve;
|
|
new local.Promise(function(r) { resolve = r; });
|
|
return $$utils$$isFunction(resolve);
|
|
}());
|
|
|
|
if (!es6PromiseSupport) {
|
|
local.Promise = $$es6$promise$promise$$default;
|
|
}
|
|
};
|
|
|
|
var es6$promise$umd$$ES6Promise = {
|
|
Promise: $$es6$promise$promise$$default,
|
|
polyfill: $$es6$promise$polyfill$$default
|
|
};
|
|
|
|
/* global define:true module:true window: true */
|
|
if (typeof define === 'function' && define['amd']) {
|
|
define(function() { return es6$promise$umd$$ES6Promise; });
|
|
} else if (typeof module !== 'undefined' && module['exports']) {
|
|
module['exports'] = es6$promise$umd$$ES6Promise;
|
|
} else if (typeof this !== 'undefined') {
|
|
this['ES6Promise'] = es6$promise$umd$$ES6Promise;
|
|
}
|
|
}).call(this);
|