Now we come to a special method generated by JS.Class, called callSuper(). This method gets created dynamically inside method calls and allows you to access the current method in the parent class. Similar to Ruby, you don’t have to pass any arguments to callSuper(), thus avoiding repetition. The arguments given to the current method are automatically passed by callSuper() up to the parent method.
var rex = new Dog('Rex');
rex.speak('barking')
// -> "MY NAME IS REX AND I LIKE BARKING!"
...
You can pass arguments to callSuper() to override the ones passed in automatically, e.g.: