tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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invoke-resolve-get-once-multiple-calls.js (1165B)


      1 // Copyright (C) 2019 Leo Balter. All rights reserved.
      2 // This code is governed by the BSD license found in the LICENSE file.
      3 
      4 /*---
      5 description: >
      6  Gets constructor's `resolve` method once from zero to many invocations.
      7 esid: sec-promise.all
      8 info: |
      9  Runtime Semantics: PerformPromiseAll
     10 
     11  1. Let promiseResolve be ? Get(constructor, `"resolve"`).
     12  1. If IsCallable(promiseResolve) is false, throw a TypeError exception.
     13  ...
     14  1. Repeat,
     15    ...
     16    1. Let nextPromise be ? Call(promiseResolve, constructor, « nextValue »).
     17 ---*/
     18 
     19 var p1 = Promise.resolve(1);
     20 var p2 = Promise.resolve(1);
     21 var p3 = Promise.reject(1);
     22 var p4 = Promise.resolve(1);
     23 var resolve = Promise.resolve;
     24 var getCount = 0;
     25 var callCount = 0;
     26 
     27 Object.defineProperty(Promise, 'resolve', {
     28  configurable: true,
     29  get() {
     30    getCount += 1;
     31    return function() {
     32      callCount += 1;
     33      return resolve.apply(Promise, arguments);
     34    };
     35  }
     36 });
     37 
     38 Promise.all([p1, p2, p3, p4]);
     39 
     40 assert.sameValue(
     41  getCount, 1, 'Got `resolve` only once for each iterated value'
     42 );
     43 assert.sameValue(
     44  callCount, 4, '`resolve` invoked once for each iterated value'
     45 );
     46 
     47 reportCompare(0, 0);