JS: Confusion about inheritance

Question

I am familiar with OOP concepts through the languages like C++, Java. Right now I am trying to learn JavaScript as a hobby, mainly due to the interest in WebGL. But I am hav

Answer 1

@@@ 2. Derived.prototype = new Base; is creating an instance of Base and this will remain in memory always (assuming Derived is defined in global space). What to do if Base class is very costly and I don't want an extra object?

Yea. This example is a inheritance-learning style. For using in your application, try:

    function F() {}
    F.prototype = Base.prototype; // Linking to Base's prototype

    Derived.prototype = new F(); // The least memory-consumption object.
    Derived.prototype.constructor = Base; // Constructor reference correction

@@@ 1. What to do with data members in prototype object (_n in this example)?

Using the above prototype-chain, we are not creating any instance of Base. So, this question is invalidated.