| // 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)); |
