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// Copyright (C) 2022 Apple Inc. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-array.prototype.unshift
description: >
A TypeError is thrown when "length" is [[Set]] on an array with non-writable "length".
info: |
Array.prototype.unshift ( ...items )
[...]
4. If argCount > 0, then
[...]
d. Let j be +0𝔽.
e. For each element E of items, do
i. Perform ? Set(O, ! ToString(j), E, true).
ii. Set j to j + 1𝔽.
5. Perform ? Set(O, "length", 𝔽(len + argCount), true).
OrdinarySetWithOwnDescriptor ( O, P, V, Receiver, ownDesc )
[...]
2. If IsDataDescriptor(ownDesc) is true, then
a. If ownDesc.[[Writable]] is false, return false.
Set ( O, P, V, Throw )
[...]
1. Let success be ? O.[[Set]](P, V, O).
2. If success is false and Throw is true, throw a TypeError exception.
---*/
var array = [];
var arrayPrototypeSet0Calls = 0;
Object.defineProperty(Array.prototype, "0", {
set(_val) {
Object.defineProperty(array, "length", { writable: false });
arrayPrototypeSet0Calls++;
},
});
assert.throws(TypeError, function() {
array.unshift(1);
});
assert(!array.hasOwnProperty(0));
assert.sameValue(array.length, 0);
assert.sameValue(arrayPrototypeSet0Calls, 1);
reportCompare(0, 0);
|