Javascript Data Structure Queue

var q = new Queue();
console.log(q.size());//from   w w w .j a  v a  2s. c  o m

q.enqueue("John");
q.enqueue("Jack");

q.enqueue("camila");

console.log(q.size());
console.log(q.isEmpty());
console.log(q.dequeue());


function Queue(){

  var items = [];


  this.enqueue = function(item){
    items.push(item);
  };

  this.dequeue = function(){
    return items.shift();
  },

  this.front = function(){
    return items[0];
  },

  this.isEmpty = function(){
    return items.length == 0;
  },
  
  this.size = function(){
    return items.length;
  }


}