Source code
Revision control
Copy as Markdown
Other Tools
// |reftest| async
// Copyright (C) 2023 Igalia, S.L. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-array.fromasync
description: >
Promise is rejected if length property on an instance of a custom this-value
is non-writable
info: |
3.j.ii.4.a. Perform ? Set(_A_, *"length"*, 𝔽(_k_), *true*).
...
3.k.viii. Perform ? Set(_A_, *"length"*, 𝔽(_len_), *true*).
Note that there is no difference between strict mode and sloppy mode, because
we are not following runtime evaluation semantics.
includes: [asyncHelpers.js]
flags: [async]
features: [Array.fromAsync]
---*/
asyncTest(async function () {
function MyArray() {
Object.defineProperty(this, "length", {
enumerable: true,
writable: false,
configurable: true,
value: 99
});
}
await assert.throwsAsync(TypeError, () => Array.fromAsync.call(MyArray, [0, 1, 2]), "Setting read-only length fails");
await assert.throwsAsync(TypeError, () => Array.fromAsync.call(MyArray, {
length: 3,
0: 0,
1: 1,
2: 2
}), "Setting read-only length fails in array-like case");
});