var Singleton = (function(){

  var instance;

  function init() {

    var privateVariable = '';

    function privateMethod() {

      console.log('i am a private method!');

    }

    return {

      publicMethod: function(){

         console.log('i am a public method!');

      },

      publicProperty: ''

    }

  }

  return {

    getInstance: function(){

      if(!instance){

        instance = init();

      }

      return  instance;

    }

  }

})()