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// Copyright (C) 2020 Rick Waldron. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-array.prototype.at
description: >
Returns the item value at the specified relative index
info: |
Array.prototype.at ( )
Let O be ? ToObject(this value).
Let len be ? LengthOfArrayLike(O).
Let relativeIndex be ? ToInteger(index).
If relativeIndex ≥ 0, then
Let k be relativeIndex.
Else,
Let k be len + relativeIndex.
If k < 0 or k ≥ len, then return undefined.
Return ? Get(O, ! ToString(k)).
features: [Array.prototype.at]
---*/
assert.sameValue(
typeof Array.prototype.at,
'function',
'The value of `typeof Array.prototype.at` is expected to be "function"'
);
let a = [1, 2, 3, 4, ,5];
assert.sameValue(a.at(0), 1, 'a.at(0) must return 1');
assert.sameValue(a.at(-1), 5, 'a.at(-1) must return 5');
assert.sameValue(a.at(-2), undefined, 'a.at(-2) returns undefined');
assert.sameValue(a.at(-3), 4, 'a.at(-3) must return 4');
assert.sameValue(a.at(-4), 3, 'a.at(-4) must return 3');
reportCompare(0, 0);
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