Nodejs Utililty Methods Array Has Duplicate

Description

The list of methods to do Array Has Duplicate are organized into topic(s).

Method

Array.prototype.hasDuplicates = function() {
    this.sort();
    for (var i = 1; i < this.length; i++) {
        if (this[i - 1] == this[i]) {
            return true;
    return false;
};
...

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;

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;