mirror of https://github.com/tc39/test262.git
30 lines
876 B
JavaScript
30 lines
876 B
JavaScript
// Copyright (C) 2016 the V8 project authors. 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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es6id: 23.3.1
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description: Subclassing the WeakMap object
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info: |
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23.3.1 The WeakMap Constructor
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...
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The WeakMap constructor is designed to be subclassable. It may be used as the
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value in an extends clause of a class definition. Subclass constructors that
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intend to inherit the specified WeakMap behaviour must include a super call to
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the WeakMap constructor to create and initialize the subclass instance with
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the internal state necessary to support the WeakMap.prototype built-in
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methods.
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features: [WeakMap]
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---*/
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class WM extends WeakMap {}
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var map = new WM();
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var obj = {};
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assert.sameValue(map.has(obj), false);
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map.set(obj, 42);
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assert.sameValue(map.has(obj), true);
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assert.sameValue(map.get(obj), 42);
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