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- '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 = 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 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;
- }
-
- exports.resolve = resolve;
- function resolve(value) {
- if (value instanceof this) {
- return value;
- }
- return handlers.resolve(new this(INTERNAL), value);
- }
-
- exports.reject = reject;
- function reject(reason) {
- var promise = new this(INTERNAL);
- return handlers.reject(promise, reason);
- }
-
- exports.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);
- }
- }
- }
- }
-
- exports.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);
- }
- });
- }
- }
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