Javascript reduce duplicated element

Posted on | Edited on

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Array.prototype.unique = function(){
  var result = []; // creat a variable to store the result
  var hash = {}; // create a hash element
  var type = null;
  this.forEach(function(e){
    type = typeof(e);
    hash[e] || (hash[e] = []); // if current element is already in hash, do nothing. Otherwise create an attribute based on current element
    if(hash[e].indexOf(type) < 0) 
    {
      result.push(e); 
      hash[e].push(type);
    }
  });
  return result;
}