Protecting objects in JavaScript

Here's another cool trick for making attributes of an object private:

  function MyObj() {
    var data = {
            id: 123,
            name: "Johnny Appleseed"
        },
        obj = {};

    obj.printName = function() {
        console.log(data.name);
    };

    obj.changeName = function(name) {
        data.name = name;
    };

    return obj;
  }
  
  x = MyObj();
  
  x.printName();
  x.changeName("Igor");
  x.printName();