es6.array.last-index-of.js

'use strict';
var $export = require('./_export');
var toIObject = require('./_to-iobject');
var toInteger = require('./_to-integer');
var toLength = require('./_to-length');
var $native = [].lastIndexOf;
var NEGATIVE_ZERO = !!$native && 1 / [1].lastIndexOf(1, -0) < 0;

$export($export.P + $export.F * (NEGATIVE_ZERO || !require('./_strict-method')($native)), 'Array', {
  // 22.1.3.14 / 15.4.4.15 Array.prototype.lastIndexOf(searchElement [, fromIndex])
  lastIndexOf: function lastIndexOf(searchElement /* , fromIndex = @[*-1] */) {
    // convert -0 to +0
    if (NEGATIVE_ZERO) return $native.apply(this, arguments) || 0;
    var O = toIObject(this);
    var length = toLength(O.length);
    var index = length - 1;
    if (arguments.length > 1) index = Math.min(index, toInteger(arguments[1]));
    if (index < 0) index = length + index;
    for (;index >= 0; index--) if (index in O) if (O[index] === searchElement) return index || 0;
    return -1;
  }
});