Nodejs Array Sort sortByFrequency()

Method Source Code

Array.prototype.sortByFrequency = function () {
   var freq = {};
   this.map(function(e, i, a){
      if(e in freq){
         freq[e]++;/*from   w  ww  . j av  a 2 s  .c  o m*/
      } else {
         freq[e] = 1;
      }
   });

   return this.sort(function(a, b){
      return freq[a] - freq[b];
   });
};

Related

1. sortBy(index,sort)

   Array.prototype.sortBy = function(index,sort){
       index = index || 0;
       sort = sort || "asc";
       var i, j, t, len = this.length;
       for(i = 0 ; i < len ; i ++){
           for(j = 1 ; j < len ; j++){
               if(this[j].charCodeAt(index >= 0 ? index : this[j].length+index) > this[j-1].charCodeAt(index >= 0 ? index : this[j-1].length+index)){
                   if(sort === "asc"){
                   }else{
   ...
   

2. sortBy(keySelector)

   Array.prototype.sortBy = function (keySelector) {
       return this.slice().sort(function(a,b) {
           var aKey = keySelector(a),
               bKey = keySelector(b);
           if (aKey > bKey) {
               return 1;
           else if (bKey > aKey) {
               return -1;
   ...
   

3. sortBy(p)

   Array.prototype.sortBy = function(p) {
     return this.slice(0).sort(function(a,b) {
       return (a[p] > b[p]) ? 1 : (a[p] < b[p]) ? -1 : 0;
     });
   };
   

4. sortBy(p, type)

   Array.prototype.sortBy = function(p, type) {
     if(type == undefined) type = "asc";
     if(type == "desc"){
       return this.slice(0).sort(function(a,b) {
         return (a[p] < b[p]) ? 1 : (a[p] > b[p]) ? -1 : 0;
       });        
     } else {
       return this.slice(0).sort(function(a,b) {
         return (a[p] > b[p]) ? 1 : (a[p] < b[p]) ? -1 : 0;
   ...
   

5. sortByDesc(f)

   Array.prototype.sortByDesc = function (f) {
       return this.sort(function (a, b) {
           if (a[f] < b[f])
               return 1;
           if (a[f] > b[f])
               return -1;
           return 0;
       });
   };
   ...
   

6. sortByID()

   var library = [ 
          title:  'The Road Ahead',
          author: 'Bill Gates',
          libraryID: 1254
      },
          title: 'Walter Isaacson',
          author: 'Steve Jobs',
   ...
   

7. sortByID(argument)

   'use strict';
   Array.prototype.sortByID = function(argument){
     this.sort(function(x,y){
       return x.libraryID > y.libraryID;
     });
   };
   var library = [ 
          title:  'The Road Ahead',
   ...
   

8. sortByKeysortByKey(key, dsc)

   Array.prototype.sortByKey = function sortByKey(key, dsc) {
     return this.sort(function(a, b) {
         var x = a[key]; 
         var y = b[key];
         if (dsc ==='dsc') {
           return (x === undefined && y === undefined ? 0 : (x < y) || x === undefined ? 1 : ((x > y) || y === undefined ? -1 : 0));
         return (x === undefined && y === undefined ? 0 : (x < y) || x === undefined ? -1 : ((x > y) || y === undefined ? 1 : 0)); 
     });
   ...
   

9. sortByNumber()

   Array.prototype.sortByNumber = function() {
    return this.sort(function(a, b) { return a - b; });