test/built-ins/Array/prototype/lastIndexOf/15.4.4.15-8-a-14.js


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// Copyright (c) 2012 Ecma International.  All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
esid: sec-array.prototype.lastindexof
es5id: 15.4.4.15-8-a-14
description: >
    Array.prototype.lastIndexOf -  deleting property of prototype
    causes prototype index property not to be visited on an Array
---*/

var arr = [0, , 2];

Object.defineProperty(arr, "20", {
  get: function() {
    delete Array.prototype[1];
    return 0;
  },
  configurable: true
});

Array.prototype[1] = 1;

assert.sameValue(arr.lastIndexOf(1), -1, 'arr.lastIndexOf(1)');