| 'use strict'; |
| var toIndexedObject = require('../internals/to-indexed-object'); |
| var toInteger = require('../internals/to-integer'); |
| var toLength = require('../internals/to-length'); |
| var arrayMethodIsStrict = require('../internals/array-method-is-strict'); |
| var arrayMethodUsesToLength = require('../internals/array-method-uses-to-length'); |
| |
| var min = Math.min; |
| var nativeLastIndexOf = [].lastIndexOf; |
| var NEGATIVE_ZERO = !!nativeLastIndexOf && 1 / [1].lastIndexOf(1, -0) < 0; |
| var STRICT_METHOD = arrayMethodIsStrict('lastIndexOf'); |
| // For preventing possible almost infinite loop in non-standard implementations, test the forward version of the method |
| var USES_TO_LENGTH = arrayMethodUsesToLength('indexOf', { ACCESSORS: true, 1: 0 }); |
| var FORCED = NEGATIVE_ZERO || !STRICT_METHOD || !USES_TO_LENGTH; |
| |
| // `Array.prototype.lastIndexOf` method implementation |
| // https://tc39.github.io/ecma262/#sec-array.prototype.lastindexof |
| module.exports = FORCED ? function lastIndexOf(searchElement /* , fromIndex = @[*-1] */) { |
| // convert -0 to +0 |
| if (NEGATIVE_ZERO) return nativeLastIndexOf.apply(this, arguments) || 0; |
| var O = toIndexedObject(this); |
| var length = toLength(O.length); |
| var index = length - 1; |
| if (arguments.length > 1) index = min(index, toInteger(arguments[1])); |
| if (index < 0) index = length + index; |
| for (;index >= 0; index--) if (index in O && O[index] === searchElement) return index || 0; |
| return -1; |
| } : nativeLastIndexOf; |