17 lines
584 B
JavaScript
17 lines
584 B
JavaScript
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// Copyright 2018 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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const arr = [1, , 3];
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function mapper(x) {
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Array.prototype[1] = 2;
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return x + 1;
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}
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// This iterates over arr using the iterator protocol, which turns the hole into
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// undefined. The mapper function then gets called in a separate iteration over
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// the acquired elements, where it increments undefined, which produces NaN and
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// gets converted to 0.
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assertArrayEquals([2, 0, 4], Uint16Array.from(arr, mapper));
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