Nodejs Array Shuffle shuffle(maxLength)

Method Source Code

/////////////////////
// Array extension //
/////////////////////
Array.prototype.shuffle = function (maxLength) {
    // http://stackoverflow.com/questions/2450954/how-to-randomize-shuffle-a-javascript-array
    var currentIndex = this.length
    var temporaryValue;
    var randomIndex;
    var result;/* w  ww . ja  va  2s. c om*/

    maxLength = maxLength || this.length

    // While there remain elements to shuffle...
    while (0 !== currentIndex) {

      // Pick a remaining element...
      randomIndex = Math.floor(Math.random() * currentIndex);
      currentIndex -= 1;

      // And swap it with the current element.
      temporaryValue = this[currentIndex];
      this[currentIndex] = this[randomIndex];
      this[randomIndex] = temporaryValue;
    }

    return this.slice(0, maxLength);
};

Related

1. shuffle()

   Array.prototype.shuffle = function() {
       for (var j, x, i = this.length - 1; i; j = randomNumber(i), x = this[--i], this[i] = this[j], this[j] = x);
       return this;
   };
   

2. shuffle()

   Array.prototype.shuffle = function () {
       var c = this.slice(0);
       for (var j, x, i = this.length; i; j = parseInt(Math.random() * i), x = this[--i], this[i] = this[j], this[j] = x);
       if (this.compare(c)) {
           this.shuffle();
       return this;
   }; 
   

3. shuffle()

   Array.prototype.shuffle = function(){
     var counter = this.length, temp, index;
       while (counter > 0){
         index = Math.floor(Math.random() * counter);
         counter--;
         temp = this[counter];
         this[counter] = this[index]
         this[index] = temp;
       };
   ...
   

4. shuffle()

   Array.prototype.shuffle = function(){
     var counter = this.length, temp, index;
     while (counter > 0) {
       index = (Math.random() * counter--) | 0;
       temp = this[counter];
       this[counter] = this[index];
       this[index] = temp;
     return this;
   ...
   

5. shuffle(b)

   function random(min, max) 
     return Math.floor(Math.random() * (max - min + 1)) + min; 
   };
   function getRandomColor()
     return 'rgb(' + random(0, 255) + ', ' + random(0, 255) + ', ' + random(0, 255) + ')';
   };
   function generateRandomSymbols()
   ...
   

6. shuffle(n)

   Array.prototype.shuffle = function (n) {
       var params = [].slice.call(arguments);
       var index = -1,
           result = this,
           length = result.length,
           lastIndex = length - 1;
       while (++index < n) {
           var rand = index + Math.floor(Math.random() * (lastIndex - index + 1));
               value = result[rand];
   ...
   

7. shuffle(times)

   Array.prototype.shuffle = function(times) {
       if(undefined === times) times = this.length * 2;
       var temp;
       while(times--) {
           var a = Number.random(0, this.length - 1);
           var b = Number.random(0, this.length - 1);
           temp = this[a];
           this[a] = this[b];
           this[b] = temp;
   ...
   

8. shuffleMe()

   Array.prototype.shuffleMe = function() {
       var array_length = this.length;
       var loop_no = array_length;
       while (--loop_no > 0) {
           var random_number = Math.floor(Math.random() * (loop_no + 1));
           var value = this[random_number];
           this[random_number] = this[loop_no];
           this[loop_no] = value;
       return this;
   var array = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H'];
   var result = array.shuffleMe();
   console.log(result);
   

9. shuffled()

   Array.prototype.shuffled = function() {
     return this.map(function(n){ return [Math.random(), n] })
                .sort().map(function(n){ return n[1] });
   };