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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-%typedarray%.prototype.lastindexof
description: Returns -1 if buffer is detached after ValidateTypedArray
info: |
%TypedArray%.prototype.lastIndexOf ( searchElement [ , fromIndex ] )
The interpretation and use of the arguments of %TypedArray%.prototype.lastIndexOf are the same as for Array.prototype.lastIndexOf as defined in 22.1.3.17.
When the lastIndexOf method is called with one or two arguments, the following steps are taken:
Let O be the this value.
Perform ? ValidateTypedArray(O).
Let len be O.[[ArrayLength]].
If len is 0, return -1F.
If fromIndex is present, let n be ? ToIntegerOrInfinity(fromIndex); else let n be len - 1.
If n is -∞, return -1F.
If n ≥ 0, then
Let k be min(n, len - 1).
Else,
Let k be len + n.
Repeat, while k ≥ 0,
Let kPresent be ! HasProperty(O, ! ToString(F(k))).
If kPresent is true, then
Let elementK be ! Get(O, ! ToString(F(k))).
Let same be the result of performing Strict Equality Comparison searchElement === elementK.
If same is true, return F(k).
Set k to k - 1.
Return -1F.
includes: [testTypedArray.js, detachArrayBuffer.js]
features: [align-detached-buffer-semantics-with-web-reality, TypedArray]
---*/
testWithTypedArrayConstructors(function(TA) {
const sample = new TA(1);
const fromIndex = {
valueOf() {
$DETACHBUFFER(sample.buffer);
return 0;
}
};
assert.sameValue(sample.lastIndexOf(undefined, fromIndex), -1);
});
reportCompare(0, 0);
|