2
0
MasterPassword/platform-independent/web/js/promise-polyfill.js

186 lines
4.6 KiB
JavaScript
Raw Normal View History

(function() {
var root;
if (typeof window === 'object' && window) {
root = window;
} else {
root = global;
}
if (typeof module !== 'undefined' && module.exports) {
module.exports = root.Promise ? root.Promise : Promise;
} else if (!root.Promise) {
root.Promise = Promise;
}
// Use polyfill for setImmediate for performance gains
var asap = root.setImmediate || function(fn) { setTimeout(fn, 1); };
// Polyfill for Function.prototype.bind
function bind(fn, thisArg) {
return function() {
fn.apply(thisArg, arguments);
}
}
var isArray = Array.isArray || function(value) { return Object.prototype.toString.call(value) === "[object Array]" };
function Promise(fn) {
if (typeof this !== 'object') throw new TypeError('Promises must be constructed via new');
if (typeof fn !== 'function') throw new TypeError('not a function');
this._state = null;
this._value = null;
this._deferreds = []
doResolve(fn, bind(resolve, this), bind(reject, this))
}
function handle(deferred) {
var me = this;
if (this._state === null) {
this._deferreds.push(deferred);
return
}
asap(function() {
var cb = me._state ? deferred.onFulfilled : deferred.onRejected
if (cb === null) {
(me._state ? deferred.resolve : deferred.reject)(me._value);
return;
}
var ret;
try {
ret = cb(me._value);
}
catch (e) {
deferred.reject(e);
return;
}
deferred.resolve(ret);
})
}
function resolve(newValue) {
try { //Promise Resolution Procedure: https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
if (newValue === this) throw new TypeError('A promise cannot be resolved with itself.');
if (newValue && (typeof newValue === 'object' || typeof newValue === 'function')) {
var then = newValue.then;
if (typeof then === 'function') {
doResolve(bind(then, newValue), bind(resolve, this), bind(reject, this));
return;
}
}
this._state = true;
this._value = newValue;
finale.call(this);
} catch (e) { reject.call(this, e); }
}
function reject(newValue) {
this._state = false;
this._value = newValue;
finale.call(this);
}
function finale() {
for (var i = 0, len = this._deferreds.length; i < len; i++) {
handle.call(this, this._deferreds[i]);
}
this._deferreds = null;
}
function Handler(onFulfilled, onRejected, resolve, reject){
this.onFulfilled = typeof onFulfilled === 'function' ? onFulfilled : null;
this.onRejected = typeof onRejected === 'function' ? onRejected : null;
this.resolve = resolve;
this.reject = reject;
}
/**
* Take a potentially misbehaving resolver function and make sure
* onFulfilled and onRejected are only called once.
*
* Makes no guarantees about asynchrony.
*/
function doResolve(fn, onFulfilled, onRejected) {
var done = false;
try {
fn(function (value) {
if (done) return;
done = true;
onFulfilled(value);
}, function (reason) {
if (done) return;
done = true;
onRejected(reason);
})
} catch (ex) {
if (done) return;
done = true;
onRejected(ex);
}
}
Promise.prototype['catch'] = function (onRejected) {
return this.then(null, onRejected);
};
Promise.prototype.then = function(onFulfilled, onRejected) {
var me = this;
return new Promise(function(resolve, reject) {
handle.call(me, new Handler(onFulfilled, onRejected, resolve, reject));
})
};
Promise.all = function () {
var args = Array.prototype.slice.call(arguments.length === 1 && isArray(arguments[0]) ? arguments[0] : arguments);
return new Promise(function (resolve, reject) {
if (args.length === 0) return resolve([]);
var remaining = args.length;
function res(i, val) {
try {
if (val && (typeof val === 'object' || typeof val === 'function')) {
var then = val.then;
if (typeof then === 'function') {
then.call(val, function (val) { res(i, val) }, reject);
return;
}
}
args[i] = val;
if (--remaining === 0) {
resolve(args);
}
} catch (ex) {
reject(ex);
}
}
for (var i = 0; i < args.length; i++) {
res(i, args[i]);
}
});
};
Promise.resolve = function (value) {
if (value && typeof value === 'object' && value.constructor === Promise) {
return value;
}
return new Promise(function (resolve) {
resolve(value);
});
};
Promise.reject = function (value) {
return new Promise(function (resolve, reject) {
reject(value);
});
};
Promise.race = function (values) {
return new Promise(function (resolve, reject) {
for(var i = 0, len = values.length; i < len; i++) {
values[i].then(resolve, reject);
}
});
};
})();