Nodejs Utililty Methods Array Unique

Array.prototype.unique = function(){
  var new_array = [];
  var index = 0;
  var value = null;
  for( count=0; count < this.length; count++){
    value = this[count];
    if( new_array.indexOf(value)==-1 ){
      new_array[index++] = value;
  return new_array;
};

Array.prototype.unique = function () {
    var arrVal = this;
    var uniqueArr = [];
    for (var i = arrVal.length; i--; ) {
        var val = arrVal[i];
        if ($.inArray(val, uniqueArr) === -1) {
            uniqueArr.unshift(val);
    return uniqueArr;

Array.prototype.unique = function() {
    var u = this.concat().sort();
    for (var i = 1; i < u.length; ) {
        if (u[i-1] === u[i])
            u.splice(i,1);
        else
            i++;
    return u;
...

Array.prototype.unique = function() {
  return this.reduce(function(accum, current) {
    if (accum.indexOf(current) < 0) {
      accum.push(current);
    return accum;
  }, []);

Array.prototype.unique = function() {
  var res = [this[0]],
    obj = {};
  for (var i = 1; i < this.length; i++) {
    if (!obj[this[i]]) {
      res.push(this[i]);
      obj[this[i]] = 1;
  return res;
var arr = ['h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd', '!'];
console.log(arr.unique())

Array.prototype.unique = function()
    var tmp = {}, out = [];
    for(var i = 0, n = this.length; i < n; ++i)
        if(!tmp[this[i]]) { tmp[this[i]] = true; out.push(this[i]); }
    return out;
var a = [1,2,2,7,4,1,'a',0,6,9,'a'];
var b = a.unique();
console.log(a);
console.log(b);

Array.prototype.unique = function() {
  this.sort(); 
  var res = [this[0]];
  for (var i = 1; i < this.length; i++) {
    if (this[i] !== res[res.length - 1]) {
      res.push(this[i]);
  return res;
...

Array.prototype.unique = function() {
    var a = this.concat();
    for(var i=0; i<a.length; ++i) {
        for(var j=i+1; j<a.length; ++j) {
            if(a[i] === a[j])
                a.splice(j--, 1);
    return a;
...

Array.prototype.unique = function () {
  var arr = [];
  for (var i = 0; i < this.length; i++) {
    if (!arr.includes(this[i])) {
      arr.push(this[i]);
  return arr;
};
...

Array.prototype.unique = function() {
    var arr = [];
    for(var i = 0; i < this.length; i++) {
        if(!arr.contains(this[i])) {
            arr.push(this[i]);
    return arr;