Singleton Design Pattern created by aelshamy - https://repl.it/ExOP/0

Singleton Design Pattern.js

// Singleton design pattern ES5
var Singleton = (function(){
  var instant;
  function createInstant(){
    var object = new Object("Iam instant");
    return object;
  }
  return {
    getInstant:function(){
      
      if(!instant){
        instant = createInstant();
      }
      
      return instant;
    }
  }
}());



var x1 = Singleton.getInstant();
var x2 = Singleton.getInstant();

console.log(x1 == x2);


// Singleton design pattern ES6
class UserObject{
  constractor(){
    if(!UserObject.instant){
      this._data = [];
      UserObject.instance = this;
    }
     return UserObject.instance;
  }
  
  add(item){
    this._data.push(item);
  }
  get(id){
      return this._data.find(d => d.id === id);
  }
  
}

const instant = new UserObject();
Object.freeze(instant);

//export default UserObject;