1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
author: André Bargull
esid: sec-arraysetlength
description: >
[[Value]] is coerced to number before descriptor validation.
info: |
ArraySetLength ( A, Desc )
[...]
3. Let newLen be ? ToUint32(Desc.[[Value]]).
4. Let numberLen be ? ToNumber(Desc.[[Value]]).
[...]
7. Let oldLenDesc be OrdinaryGetOwnProperty(A, "length").
[...]
11. If newLen ≥ oldLen, then
a. Return OrdinaryDefineOwnProperty(A, "length", newLenDesc).
OrdinaryDefineOwnProperty ( O, P, Desc )
[...]
3. Return ValidateAndApplyPropertyDescriptor(O, P, extensible, Desc, current).
ValidateAndApplyPropertyDescriptor ( O, P, extensible, Desc, current )
[...]
7. Else if IsDataDescriptor(current) and IsDataDescriptor(Desc) are both true, then
a. If current.[[Configurable]] is false and current.[[Writable]] is false, then
i. If Desc.[[Writable]] is present and Desc.[[Writable]] is true, return false.
features: [Reflect]
---*/
var array = [1, 2];
var valueOfCalls = 0;
var length = {
valueOf: function() {
valueOfCalls += 1;
if (valueOfCalls !== 1) {
// skip first coercion at step 3
Object.defineProperty(array, "length", {writable: false});
}
return array.length;
},
};
assert.throws(TypeError, function() {
Object.defineProperty(array, "length", {value: length, writable: true});
}, 'Object.defineProperty(array, "length", {value: length, writable: true}) throws a TypeError exception');
assert.sameValue(valueOfCalls, 2, 'The value of valueOfCalls is expected to be 2');
array = [1, 2];
valueOfCalls = 0;
assert(
!Reflect.defineProperty(array, "length", {value: length, writable: true}),
'The value of !Reflect.defineProperty(array, "length", {value: length, writable: true}) is expected to be true'
);
assert.sameValue(valueOfCalls, 2, 'The value of valueOfCalls is expected to be 2');
reportCompare(0, 0);
|
