fastest_unique_algorithm.js

/* 
  @author http://www.shamasis.net/2009/09/fast-algorithm-to-find-unique-items-in-javascript-array/
*/

// prototype
Array.prototype.unique = function() {
    var o = {}, i, r = [];
    var l = this.length;
  
    for (i = 0; i < l; i++) {
      o[this[i]] = this[i];
    }
  
    for (i in o) {
      r.push(o[i]);
    }
  
    return r;
};
 
// function
var uniqueArray = function(arr){
    var o = {}, i, r=[];
    var l = arr.length;
  
    for (i = 0; i < l; i++) {
      o[arr[i]] = arr[i];
    }
  
    for (i in o) {
      r.push(o[i]);
    }
  
    return r;
};