SOURCE

function mySet (){
  var collection = [];
  
  this.has = function(element){
    return (collection.indexOf(element) != -1);
  }
  
  this.value = function(){
    return collection;
  }
  
  this.add = function(element){
    if (!this.has(element)){
      collection.push(element);
    }
    return false;
  }
  
  this.remove = function(element){
    if(collection.indexOf(element) == -1){
      return false;
    }
    else{
        collection.splice(element,1);
    }
  }
}

var myset = new mySet();
myset.add(1);
myset.add(2);
myset.remove(0);
console.log(myset.value());