37 lines
1.2 KiB
JavaScript
37 lines
1.2 KiB
JavaScript
'use strict';
|
|
|
|
var GetIntrinsic = require('get-intrinsic');
|
|
|
|
var $TypeError = GetIntrinsic('%TypeError%');
|
|
|
|
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
|
|
};
|