blob: 90fdbad630c4e72bacd91e02feca8a8a0aa4a69d (
plain)
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
|
// 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: 15.4.4.15-4-8
description: >
Array.prototype.lastIndexOf returns -1 if 'length' is 0 (length is
an empty array)
---*/
// objects inherit the default valueOf method of the Object object;
// that simply returns the 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.
//
// The toString( ) method on Array converts the array elements to strings,
// then returns the result of concatenating these strings, with commas in
// between. An array with no elements converts to the empty string, which
// converts to the number 0. If an array has a single element that is a
// number n, the array converts to a string representation of n, which is
// then converted back to n itself. If an array contains more than one element,
// or if its one element is not a number, the array converts to NaN.
var i = Array.prototype.lastIndexOf.call({length: [ ]}, 1);
assert.sameValue(i, -1, 'i');
|
