1// 21.1.3.18 String.prototype.startsWith(searchString [, position ]) 2'use strict'; 3var $export = require('./_export'); 4var toLength = require('./_to-length'); 5var context = require('./_string-context'); 6var STARTS_WITH = 'startsWith'; 7var $startsWith = ''[STARTS_WITH]; 8 9$export($export.P + $export.F * require('./_fails-is-regexp')(STARTS_WITH), 'String', { 10 startsWith: function startsWith(searchString /* , position = 0 */) { 11 var that = context(this, searchString, STARTS_WITH); 12 var index = toLength(Math.min(arguments.length > 1 ? arguments[1] : undefined, that.length)); 13 var search = String(searchString); 14 return $startsWith 15 ? $startsWith.call(that, search, index) 16 : that.slice(index, index + search.length) === search; 17 } 18}); 19