tor-browser

The Tor Browser
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this-constructor-with-readonly-length.js (1151B)

      1 // |reftest| async
      2 // Copyright (C) 2023 Igalia, S.L. All rights reserved.
      3 // This code is governed by the BSD license found in the LICENSE file.
      4 
      5 /*---
      6 esid: sec-array.fromasync
      7 description: >
      8  Promise is rejected if length property on an instance of a custom this-value
      9  is non-writable
     10 info: |
     11  3.j.ii.4.a. Perform ? Set(_A_, *"length"*, 𝔽(_k_), *true*).
     12  ...
     13  3.k.viii. Perform ? Set(_A_, *"length"*, 𝔽(_len_), *true*).
     14 
     15  Note that there is no difference between strict mode and sloppy mode, because
     16  we are not following runtime evaluation semantics.
     17 includes: [asyncHelpers.js]
     18 flags: [async]
     19 features: [Array.fromAsync]
     20 ---*/
     21 
     22 asyncTest(async function () {
     23  function MyArray() {
     24    Object.defineProperty(this, "length", {
     25      enumerable: true,
     26      writable: false,
     27      configurable: true,
     28      value: 99
     29    });
     30  }
     31 
     32  await assert.throwsAsync(TypeError, () => Array.fromAsync.call(MyArray, [0, 1, 2]), "Setting read-only length fails");
     33  await assert.throwsAsync(TypeError, () => Array.fromAsync.call(MyArray, {
     34    length: 3,
     35    0: 0,
     36    1: 1,
     37    2: 2
     38  }), "Setting read-only length fails in array-like case");
     39 });