Here you can find the source of contains(item)
Array.prototype.contains = function (item) { return RegExp("\\b"+item+"\\b").test(this); };
Array.prototype.contains = function(i) { return this.indexOf(i) > -1; };
var twoSum = function(nums, target) { for (var i = nums.length - 1; i >= 0; i--) { let val = target - nums[i]; if (nums.contains(i, val) === true) { return [nums.indexOf(val), i]; return []; }; ...
Array.prototype.contains = function (item) { return this.indexOf(item) != -1
Array.prototype.contains = function(item) { return this.indexOf(item) !== -1; };
Array.prototype.contains = function(item){ return RegExp("(^|,)" + item.toString() + "($|,)").test(this); };
Array.prototype.contains = function(item) { if (typeof(item) === 'function') { return this.some(item); return this.indexOf(item) >= 0; };
Array.prototype.contains = function(item) { return this.indexOf(item) === -1 ? false : true
Array.prototype.contains = function (item) { for (i in this) { if (this[i] === item) { return true; return false; };
Array.prototype.contains = function (item) { for (var i=0; i<this.length; ++i) if (this[i] == item) return true; return false; };