| // Copyright 2018 the V8 project authors. All rights reserved. | |
| // Use of this source code is governed by a BSD-style license that can be | |
| // found in the LICENSE file. | |
| const arr = [1, , 3]; | |
| function mapper(x) { | |
| Array.prototype[1] = 2; | |
| return x + 1; | |
| } | |
| // This iterates over arr using the iterator protocol, which turns the hole into | |
| // undefined. The mapper function then gets called in a separate iteration over | |
| // the acquired elements, where it increments undefined, which produces NaN and | |
| // gets converted to 0. | |
| assertArrayEquals([2, 0, 4], Uint16Array.from(arr, mapper)); |