Strict mode Passingnon-Strict mode Passing
Features:
- ∅
// 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 description: > Array.prototype.lastIndexOf - value of 'length' is an Object which has an own toString method ---*/ // 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 targetObj = this; var obj = { 1: targetObj, 2: 2, length: { toString: function() { return '2'; } } }; assert.sameValue(Array.prototype.lastIndexOf.call(obj, targetObj), 1, 'Array.prototype.lastIndexOf.call(obj, targetObj)'); assert.sameValue(Array.prototype.lastIndexOf.call(obj, 2), -1, 'Array.prototype.lastIndexOf.call(obj, 2)');