Different type of javascript class definitions ES5

User.js

// User Class
function User(){
  
  this.first = "Joseph";           // public property
  var middleName = "Anthony";     // private property
  
  this.last = function(){     // public method
    return "Janiga";
  };
  
  function getFullName(){     // private method
    return this.first + " " + middle + " " + this.last();
  };
  
  this.printName = function(){
    console.log(getFullName());
  };
}

var joe = new User();

joe.first; // "Joseph"
// middleName - not exposed from this scope
joe.last(); // "Janiga"
// getFullName() - not exposed outside of the class body
joe.printName(); // "Joseph Anthony Janiga" - THIS however works because the printName method has access to the class scope