ExtJS 3: Two ways of creating custom class: what's the difference?

Question

I\'m trying to learn ExtJS and object-oriented JavaScript in general. I\'ve seen people defining classes in custom namespaces in a couple of ways. What\'s the difference between

Answer 1

It's basically the same, except that you could use private variables in the self-exectuing function of the first method, while you can only define global variables in the second one.

For example:

Ext.ns('myapp.cars');
(function(){

    var carInfo = {
      goodEngine: true
    };

    var Car = Ext.extend(Object, {
       info: carInfo
    });

    myapp.cars.Car = Car;
})()

// carInfo is undefined here, so this will give an error
alert( carInfo.goodEngine );

So, the first method is quite useful if you work with a bunge of variables that you won't use later on.