Nodejs Array Unique unique()

Method Source Code

/*//w  ww.j  a  va 2  s. co m
 Array#unique
 */
Array.prototype.unique = function() {
  return this.reduce(function(prev_val, current_val) {
    if (prev_val.indexOf(current_val) < 0) {
      prev_val.push(current_val);
    }
    return prev_val;
  }, []);
};

/*
 Array#times_do
 returns an array of n results of calling a callback
 sorta like ruby's Array.new(n) { 'val' }

 ex:
 arr = [5].times_do(function(){ return 'default value';});
 */
Array.prototype.times_do = function(callback) {
  return Array.apply(null, Array(this[0])).map(callback); // todo - add i param to callback
};

Related

1. unique()

   Array.prototype.unique = function() {
       var a = [];
       for (var i=0, l=this.length; i<l; i++)
           if (a.indexOf(this[i]) === -1)
               a.push(this[i]);
       return a;
   };
   

2. unique()

   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;
   ...
   

3. unique()

   Array.prototype.unique = function() {
     return this.filter(function(item, idx, array) {
       return array.indexOf(item) === idx;
     });
   

4. unique()

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

5. unique()

   Array.prototype.unique = function() {
     var uniques = [];
     this.forEach(function(value) {
       if (uniques.indexOf(value) == -1)
         uniques.push(value);
     });
     return uniques;
   };
   

6. unique()

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

7. unique()

   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;
   ...
   

8. unique()

   var numbers = [4,5,4,4,4,5,4,5]
   function unique(arr) {
     var newArr = [];
     for (var i = 0; i < arr.length; i++) {
       if (newArr.indexOf(arr[i]) < 0) {
         newArr.push(arr[i]);
     return newArr;
   ...
   

9. unique()

   Array.prototype.unique = function(){
      var u = {}, a = [];
      for(var l = 0, i = this.length-1; i >= 0; --i){
         if(u.hasOwnProperty(this[i])) {
            continue;
         a.unshift(this[i]);
         u[this[i]] = 1;
      return a;
   };