test/built-ins/Array/prototype/lastIndexOf/15.4.4.15-5-21.js


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

// Copyright (c) 2012 Ecma International.  All rights reserved.
// Ecma International makes this code available under the terms and conditions set
// forth on http://hg.ecmascript.org/tests/test262/raw-file/tip/LICENSE (the
// "Use Terms").   Any redistribution of this code must retain the above
// copyright and this notice and otherwise comply with the Use Terms.

/*---
es5id: 15.4.4.15-5-21
description: >
    Array.prototype.lastIndexOf - value of 'fromIndex' which is an
    Object, and has an own toString method
includes: [runTestCase.js]
---*/

function testcase() {

        // objects inherit the default valueOf() method from Object
        // that simply returns itself. Since the default valueOf() method
        // does not return a primitive value, ES next tries to convert the object
        // to a number by calling its toString() method and converting the
        // resulting string to a number.
        var fromIndex = {
            toString: function () {
                return '2';
            }
        };
        var targetObj = new RegExp();

        return [0, true, targetObj, 3, false].lastIndexOf(targetObj, fromIndex) === 2 &&
        [0, true, 3, targetObj, false].lastIndexOf(targetObj, fromIndex) === -1;
    }
runTestCase(testcase);