inherit sub-object together with object

Question

I'm using objects A and AB with

A.myB = A.B;

I have an inherited A1 and A1.B where A1.B is inherited from AB and

A1.myB = A1.B;

The code to achieve this looks like this:

A = function() {
    this.myB = this.createB();
};
...
A.prototype.createB = function() {
    return new A.B();
};

Then on inheriting AI need to change .createB :

A1.prototype.createB = function() {
    return new A1.B1();
};

I think I'm overlooking something - is there a more straightforward way to set this up, without the need for changing createB ?

Answer 1

Alright, while writing this I found an answer. Maybe helpful for anyone out there:

A.prototype.createB = function() {
    return new this.constructor.B();
};

I think that should do the trick and may be quite handy in combination with the subobject being defined as a property of the main objects constructor.