JSTests/test262/test/built-ins/Array/prototype/map/15.4.4.19-8-b-14.js

// 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.map
es5id: 15.4.4.19-8-b-14
description: >
    Array.prototype.map - decreasing length of array causes index
    property not to be visited
---*/

        function callbackfn(val, idx, obj) {
            return idx === 3 && typeof val === "undefined";
        }

        var arr = [0, 1, 2, "last"];

        Object.defineProperty(arr, "0", {
            get: function () {
                arr.length = 3;
                return 0;
            },
            configurable: true
        });

        var testResult = arr.map(callbackfn);

assert.sameValue(typeof testResult[3], "undefined", 'typeof testResult[3]');