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'use strict';
var asap = require('asap');
function noop() {}
// States:
//
// 0 - pending
// 1 - fulfilled with _value
// 2 - rejected with _value
// 3 - adopted the state of another promise, _value
//
// once the state is no longer pending (0) it is immutable
// All `_` prefixed properties will be reduced to `_{random number}`
// at build time to obfuscate them and discourage their use.
// We don't use symbols or Object.defineProperty to fully hide them
// because the performance isn't good enough.
// to avoid using try/catch inside critical functions, we
// extract them to here.
var LAST_ERROR = null;
var IS_ERROR = {};
function getThen(obj) {
try {
return obj.then;
} catch (ex) {
LAST_ERROR = ex;
return IS_ERROR;
}
}
function tryCallOne(fn, a) {
try {
return fn(a);
} catch (ex) {
LAST_ERROR = ex;
return IS_ERROR;
}
}
function tryCallTwo(fn, a, b) {
try {
fn(a, b);
} catch (ex) {
LAST_ERROR = ex;
return IS_ERROR;
}
}
module.exports = Promise;
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._45 = 0;
this._81 = 0;
this._65 = null;
this._54 = null;
if (fn === noop) return;
doResolve(fn, this);
}
Promise._10 = null;
Promise._97 = null;
Promise._61 = noop;
Promise.prototype.then = function(onFulfilled, onRejected) {
if (this.constructor !== Promise) {
return safeThen(this, onFulfilled, onRejected);
}
var res = new Promise(noop);
handle(this, new Handler(onFulfilled, onRejected, res));
return res;
};
function safeThen(self, onFulfilled, onRejected) {
return new self.constructor(function (resolve, reject) {
var res = new Promise(noop);
res.then(resolve, reject);
handle(self, new Handler(onFulfilled, onRejected, res));
});
};
function handle(self, deferred) {
while (self._81 === 3) {
self = self._65;
}
if (Promise._10) {
Promise._10(self);
}
if (self._81 === 0) {
if (self._45 === 0) {
self._45 = 1;
self._54 = deferred;
return;
}
if (self._45 === 1) {
self._45 = 2;
self._54 = [self._54, deferred];
return;
}
self._54.push(deferred);
return;
}
handleResolved(self, deferred);
}
function handleResolved(self, deferred) {
asap(function() {
var cb = self._81 === 1 ? deferred.onFulfilled : deferred.onRejected;
if (cb === null) {
if (self._81 === 1) {
resolve(deferred.promise, self._65);
} else {
reject(deferred.promise, self._65);
}
return;
}
var ret = tryCallOne(cb, self._65);
if (ret === IS_ERROR) {
reject(deferred.promise, LAST_ERROR);
} else {
resolve(deferred.promise, ret);
}
});
}
function resolve(self, newValue) {
// Promise Resolution Procedure: https://github.com/promises-aplus/promises-spec#the-promise-resolution-procedure
if (newValue === self) {
return reject(
self,
new TypeError('A promise cannot be resolved with itself.')
);
}
if (
newValue &&
(typeof newValue === 'object' || typeof newValue === 'function')
) {
var then = getThen(newValue);
if (then === IS_ERROR) {
return reject(self, LAST_ERROR);
}
if (
then === self.then &&
newValue instanceof Promise
) {
self._81 = 3;
self._65 = newValue;
finale(self);
return;
} else if (typeof then === 'function') {
doResolve(then.bind(newValue), self);
return;
}
}
self._81 = 1;
self._65 = newValue;
finale(self);
}
function reject(self, newValue) {
self._81 = 2;
self._65 = newValue;
if (Promise._97) {
Promise._97(self, newValue);
}
finale(self);
}
function finale(self) {
if (self._45 === 1) {
handle(self, self._54);
self._54 = null;
}
if (self._45 === 2) {
for (var i = 0; i < self._54.length; i++) {
handle(self, self._54[i]);
}
self._54 = null;
}
}
function Handler(onFulfilled, onRejected, promise){
this.onFulfilled = typeof onFulfilled === 'function' ? onFulfilled : null;
this.onRejected = typeof onRejected === 'function' ? onRejected : null;
this.promise = promise;
}
/**
* Take a potentially misbehaving resolver function and make sure
* onFulfilled and onRejected are only called once.
*
* Makes no guarantees about asynchrony.
*/
function doResolve(fn, promise) {
var done = false;
var res = tryCallTwo(fn, function (value) {
if (done) return;
done = true;
resolve(promise, value);
}, function (reason) {
if (done) return;
done = true;
reject(promise, reason);
})
if (!done && res === IS_ERROR) {
done = true;
reject(promise, LAST_ERROR);
}
}
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