44 lines
1.6 KiB
JavaScript
44 lines
1.6 KiB
JavaScript
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// Copyright 2021 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Accessors for __proto__ are defined in Object.prototype (spec:
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// https://tc39.es/ecma262/#sec-object.prototype.__proto__ ). If
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// Object.prototype is not in the prototype chain of an object, the accessors
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// are not accessible. In particular, __proto__ is treated as a normal property
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// and the special meaning (that getting __proto__ would return the prototype
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// and setting __proto__ would change the prototype) is lost.
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function testObjectWithNullProto(object) {
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assertNull(Object.getPrototypeOf(object));
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// The __proto__ getter is not accessible.
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assertEquals(undefined, object.__proto__);
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// The __proto__ setter is not accessible. Setting __proto__ will create a
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// normal property called __proto__ and not change the prototype.
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object.__proto__ = {};
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assertNull(Object.getPrototypeOf(object));
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// Object.setPrototypeOf can still be used for really setting the prototype.
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const proto1 = {};
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Object.setPrototypeOf(object, proto1);
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// Now the accessors are accessible again.
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assertEquals(proto1, object.__proto__);
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const proto2 = {};
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object.__proto__ = proto2;
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assertEquals(proto2, object.__proto__);
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}
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(function TestObjectCreatedWithObjectCreate() {
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testObjectWithNullProto(Object.create(null));
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})();
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(function TestProtoSetToNullAfterCreation() {
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let object_with_null_proto = {};
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object_with_null_proto.__proto__ = null;
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testObjectWithNullProto(Object.create(null));
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})();
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