Nodejs Array Has Duplicate hasDuplicates()

Method Source Code

//http://stackoverflow.com/questions/19655975/check-if-an-array-contains-duplicate-values
Array.prototype.hasDuplicates = function() {
    this.sort();//  w  w w  . ja v a 2 s.  c o  m
    for (var i = 1; i < this.length; i++) {
        if (this[i - 1] == this[i]) {
            return true;
        }
    }
    return false;
};

Related

1. hasDuplicates()

   Array.prototype.hasDuplicates = function() {
       for (var i = 0; i < this.length; i++) {
           var currentVal = this[i];
           for (var j = 0; j < this.length; j++) {
               if(i === j) continue; 
               var val = this[j];
               if (currentVal === val) {
                   return true;
       return false;
   

2. isDuplicate(val)

   Array.prototype.isDuplicate = function(val) {
       for (var i = 0; i < this.length; i++) {
           var currentVal = this[i];
           if (currentVal === val) {
               return true;
       return false;