Nodejs Array Unique unique2()

Method Source Code

Array.prototype.unique2 = function () {
   var result = [];
   for (var i = 0; i < this.length; i++) {
      if (result.indexOf(this[i]) == -1) {
         result.push(this[i]);/*from  w  w  w.  j a v  a 2s . c  om*/
      }
   }
   return result;

Related

1. unique1()

   Array.prototype.unique1 = function(){
     var res = [this[0]];
     for(var i = 1; i < this.length; i++){
       var repeat = false;
       for(var j = 0; j < res.length; j++){
         if(this[i] == res[j]){
           repeat = true;
           break;
       if(!repeat){
         res.push(this[i]);
     return res;
   var arr = [1, 'a', 'a', 'b', 'd', 'e', 'e', 1, 0]
   console.log(arr.unique1());
   

2. unique1()

   Array.prototype.unique1 = function () {
     var a = [],
       o = {},
       n = this.length;
       for (var i=0; i<n; ++i) {
         o[this[i]] = this[i];
       for (var i in o) {
         a.push(o[i]);
   ...
   

3. unique2()

   Array.prototype.unique2 = 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;
   ...
   

4. unique2()

   Array.prototype.unique2=function () {
       var n={};
       var tmp=[];
       for(var i=0;i<this.length;i++){
           if(!n[this[i]]){
               n[this[i]]=true;
               tmp.push(this[i]);
       return tmp;
   

5. unique2()

   Array.prototype.unique2 = function () {
     var a = [],
       n = this.length;
       for (var i=0; i<n; ++i) {
         for (var j=i+1; j<n; ++j) {
           if(this[i]===this[j]) j = ++i;
         a.push(this[i]);
     return a;
   };
   

6. unique2(getKey = val => val)

   Array.prototype.unique2 = function (getKey = val => val) {
     const n = {};
     const r = [];
     for (let i = 0; i < this.length; i += 1) {
       const key = getKey(this[i]);
       if (!n[key]) {
         n[key] = true;
         r.push(this[i]);
     return r;
   };
   

7. unique3()

   Array.prototype.unique3 = function () {
     return this.filter(function (s, i, a) {
       return i===a.lastIndexOf(s);
     })
   };
   

8. unique3()

   Array.prototype.unique3 = function(){
    var res = [];
    var json = {};
    var dejson = {};
    var length = 0;
    for(var i = 0; i < this.length; i++){
     if(!json[this[i].name]){
      dejson[this[i]] = this[i];
      console.log(dejson[this[i]]);
   ...
   

9. unique3()

   Array.prototype.unique3 = function(){
     var res = [1,2,3,4,1,2,3,4];
     var json = {};
     for(var i = 0; i < this.length; i++){
         if(!json[this[i]]) {
           res.push(this[i]);
           json[this[i]] = true;
     return res;
   console.log(unique3());