js/src/tests/test262/built-ins/Array/prototype/at/returns-undefined-for-out-of-range-index.js


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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 undefined if the specified index less than or greater than the available index range.
info: |
  Array.prototype.at( index )

  If k < 0 or k ≥ len, then return undefined.
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 = [];

assert.sameValue(a.at(-2), undefined, 'a.at(-2) returns undefined'); // wrap around the end
assert.sameValue(a.at(0), undefined, 'a.at(0) returns undefined');
assert.sameValue(a.at(1), undefined, 'a.at(1) returns undefined');


reportCompare(0, 0);