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// Copyright (C) 2016 the V8 project authors. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
es6id: 23.3.1
description: Subclassing the WeakMap object
info: |
23.3.1 The WeakMap Constructor
...
The WeakMap constructor is designed to be subclassable. It may be used as the
value in an extends clause of a class definition. Subclass constructors that
intend to inherit the specified WeakMap behaviour must include a super call to
the WeakMap constructor to create and initialize the subclass instance with
the internal state necessary to support the WeakMap.prototype built-in
methods.
features: [WeakMap]
---*/
class WM extends WeakMap {}
var map = new WM();
var obj = {};
assert.sameValue(map.has(obj), false);
map.set(obj, 42);
assert.sameValue(map.has(obj), true);
assert.sameValue(map.get(obj), 42);
reportCompare(0, 0);