Encapsulation in Javascript and Coffeescript

encapsulation.coffee

class person
  constructor : (@name) ->
  
  doPrivateThings = () ->
    alert('Psst ' + @name + ' is doing private things.')  
    #using '=' in function declaration will make it private

  goToRestroom : ->
    alert(@name + ' is inside restroom.')
    doPrivateThings.call(this)

jim = new person('Jim')
jim.goToRestroom()

encapsulation.js

var jim, person;

person = (function() {
  var doPrivateThings;

  function person(name) {
    this.name = name;
  }

  doPrivateThings = function() {
    return alert('Psst ' + this.name + ' is doing private things.');
  };

  person.prototype.goToRestroom = function() {
    alert(this.name + ' is inside restroom.');
    return doPrivateThings.call(this);
  };

  return person;

})();

jim = new person('Jim');

jim.goToRestroom();