lix-website/themes/lix/assets/bootstrap/node_modules/es-abstract/2019/NewPromiseCapability.js
2024-04-26 22:49:34 -06:00

35 lines
1.2 KiB
JavaScript

'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
};