Nodejs Array Unique unique2()

Method Source Code

Array.prototype.unique2=function () {
    var n={};/*from ww  w.j a va2  s.  c om*/
    var tmp=[];

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

Related

1. unique(mutate)

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

2. unique(str)

   Array.prototype.unique = function(str){
     const seen = new Map()
     return this.filter((a) => {
       return !seen.has(a['name']) && seen.set(a['name'], 1)
     })
   

3. 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());
   

4. 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]);
   ...
   

5. 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;
   ...
   

6. 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;
   };
   

7. unique2()

   Array.prototype.unique2 = function () {
     var result = [];
     for (var i = 0; i < this.length; i++) {
       if (result.indexOf(this[i]) == -1) {
         result.push(this[i]);
     return result;
   

8. 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;
   };
   

9. unique3()

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