Here you can find the source of contains(element)
/** Returns true if this array contrains the specified element. */ Array.prototype.contains = function(element) { return this.indexOf(element) != -1; };
Array.prototype.contains = function(element) { var i = this.length; while(i--) { if (_.isEqual(this[i], element)) { return true; return false;
Array.prototype.contains = function(element) { return this.indexOf(element) != -1; }; Object.prototype.toString = function() { try { return JSON.stringify(this); } catch(circular_structure) { return '[object Object]'; };
Array.prototype.contains = function (element) for (var i = 0; i < this.length; i++) if (this[i] == element) return true; return false; };
'use strict'; Array.prototype.contains = function (element) { return (this.indexOf(element) !== -1); };
Array.prototype.contains = function(element) { return this.indexOf(element) != -1; };
Array.prototype.contains = function(element) { return (-1 !== this.indexOf(element))
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) for (var i = 0; i < this.length; i++) 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; };