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// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-proxy-object-internal-methods-and-internal-slots-isextensible
description: >
If "isExtensible" trap is null or undefined, [[IsExtensible]] call is
properly forwarded to [[ProxyTarget]] (which is also a Proxy object).
info: |
[[IsExtensible]] ( )
[...]
4. Let target be O.[[ProxyTarget]].
5. Let trap be ? GetMethod(handler, "isExtensible").
6. If trap is undefined, then
a. Return ? IsExtensible(target).
IsExtensible ( O )
1. Assert: Type(O) is Object.
2. Return ? O.[[IsExtensible]]().
[[IsExtensible]] ( )
[...]
7. Let booleanTrapResult be ! ToBoolean(? Call(trap, handler, « target »)).
[...]
10. Return booleanTrapResult.
features: [Proxy]
---*/
var array = [];
var arrayExtensible = true;
var arrayTarget = new Proxy(array, {
isExtensible: function() {
return arrayExtensible;
},
});
var arrayProxy = new Proxy(arrayTarget, {
isExtensible: undefined,
});
assert(Object.isExtensible(arrayProxy));
Object.preventExtensions(array);
arrayExtensible = false;
assert(!Object.isExtensible(arrayProxy));
reportCompare(0, 0);