mirror of https://github.com/tc39/test262.git
50 lines
1.2 KiB
JavaScript
50 lines
1.2 KiB
JavaScript
// Copyright (C) 2020 Alexey Shvayka. All rights reserved.
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// This code is governed by the BSD license found in the LICENSE file.
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/*---
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esid: sec-proxy-object-internal-methods-and-internal-slots-isextensible
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description: >
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If "isExtensible" trap is null or undefined, [[IsExtensible]] call is
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properly forwarded to [[ProxyTarget]] (which is also a Proxy object).
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info: |
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[[IsExtensible]] ( )
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[...]
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4. Let target be O.[[ProxyTarget]].
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5. Let trap be ? GetMethod(handler, "isExtensible").
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6. If trap is undefined, then
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a. Return ? IsExtensible(target).
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IsExtensible ( O )
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1. Assert: Type(O) is Object.
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2. Return ? O.[[IsExtensible]]().
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[[IsExtensible]] ( )
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[...]
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7. Let booleanTrapResult be ! ToBoolean(? Call(trap, handler, « target »)).
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[...]
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10. Return booleanTrapResult.
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features: [Proxy]
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---*/
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var array = [];
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var arrayExtensible = true;
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var arrayTarget = new Proxy(array, {
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isExtensible: function() {
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return arrayExtensible;
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},
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});
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var arrayProxy = new Proxy(arrayTarget, {
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isExtensible: undefined,
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});
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assert(Object.isExtensible(arrayProxy));
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Object.preventExtensions(array);
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arrayExtensible = false;
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assert(!Object.isExtensible(arrayProxy));
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