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: >
Constructs the this-value once if asyncItems is iterable, twice if not, and
length and element properties are set correctly on the result
info: |
3.e. If IsConstructor(_C_) is *true*, then
i. Let _A_ be ? Construct(_C_).
...
j. If _iteratorRecord_ is not *undefined*, then
...
k. Else,
...
iv. If IsConstructor(_C_) is *true*, then
1. Let _A_ be ? Construct(_C_, « 𝔽(_len_) »).
includes: [compareArray.js, asyncHelpers.js]
flags: [async]
features: [Array.fromAsync]
---*/
asyncTest(async function () {
const constructorCalls = [];
function MyArray(...args) {
constructorCalls.push(args);
}
let result = await Array.fromAsync.call(MyArray, [1, 2]);
assert(result instanceof MyArray, "result is an instance of the constructor this-value");
assert.sameValue(result.length, 2, "length is set on result");
assert.sameValue(result[0], 1, "element 0 is set on result");
assert.sameValue(result[1], 2, "element 1 is set on result");
assert.sameValue(constructorCalls.length, 1, "constructor is called once");
assert.compareArray(constructorCalls[0], [], "constructor is called with no arguments");
constructorCalls.splice(0); // reset
result = await Array.fromAsync.call(MyArray, {
length: 2,
0: 1,
1: 2
});
assert(result instanceof MyArray, "result is an instance of the constructor this-value");
assert.sameValue(result.length, 2, "length is set on result");
assert.sameValue(result[0], 1, "element 0 is set on result");
assert.sameValue(result[1], 2, "element 1 is set on result");
assert.sameValue(constructorCalls.length, 1, "constructor is called once");
assert.compareArray(constructorCalls[0], [2], "constructor is called with a length argument");
});