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- 'use strict';
- var $TypeError = require('es-errors/type');
- var IsCallable = require('./IsCallable');
- var IsConstructor = require('./IsConstructor');
- // https://262.ecma-international.org/6.0/#sec-newpromisecapability
- module.exports = function NewPromiseCapability(C) {
- if (!IsConstructor(C)) {
- throw new $TypeError('C must be a constructor'); // step 1
- }
- var resolvingFunctions = { '[[Resolve]]': void undefined, '[[Reject]]': void undefined }; // step 3
- var promise = new C(function (resolve, reject) { // steps 4-5
- if (typeof resolvingFunctions['[[Resolve]]'] !== 'undefined' || typeof resolvingFunctions['[[Reject]]'] !== 'undefined') {
- throw new $TypeError('executor has already been called'); // step 4.a, 4.b
- }
- resolvingFunctions['[[Resolve]]'] = resolve; // step 4.c
- resolvingFunctions['[[Reject]]'] = reject; // step 4.d
- }); // step 4-6
- if (!IsCallable(resolvingFunctions['[[Resolve]]']) || !IsCallable(resolvingFunctions['[[Reject]]'])) {
- throw new $TypeError('executor must provide valid resolve and reject functions'); // steps 7-8
- }
- return {
- '[[Promise]]': promise,
- '[[Resolve]]': resolvingFunctions['[[Resolve]]'],
- '[[Reject]]': resolvingFunctions['[[Reject]]']
- }; // step 9
- };
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