JS prototype with immediatly called function

fn_prototype.js

// define constructor
function User() {
 
}

// define prototype using "this"
User.prototype = new (function() {
  this.name = 'new User';
  var pass = 'secret'
  
  this.login = function() { ... }
  this.logout = function() { ... }
})();

// define prototype without "this"
User.prototype = (function() {
  var name = 'new User';
  var pass = 'secret'
  
  function login() { ... }
  function logout() { ... }

  return {
   login: login,
   logout: logout,
   name: name
  }
})();