Here you can find the source of contains(element)
Array.prototype.contains = function (element) { return this.indexOf(element) > -1; };
Array.prototype.contains = function(elem){ for(var i = 0; i < this.length; i++) { if(this[i] === elem) return true; return false; };
Array.prototype.contains = function(elem) { return this.indexOf(elem) >= 0
Array.prototype.contains = function(element) { return this.indexOf(element) >= 0; };
Array.prototype.contains = function(element) { return this.lastIndexOf(element) != -1; };
Array.prototype.contains = function(element){ return $.inArray(element, this); };
'use strict'; Array.prototype.contains = function(element) { return this.indexOf(element) > -1; };
Array.prototype.contains = function (element) { for (i in this) if (this[i] == element) return true; return false;
Array.prototype.contains = function (element) { for (var i = 0; i < this.length; i++) { if (this[i] == element) { return true; return false; };
Array.prototype.contains = function(element) { var i = this.length; while(i--) { if (_.isEqual(this[i], element)) { return true; return false;