CreateJS EventDispatcher and inheritance

Question

I'm trying to create a base class that has createjs EventDispatcher functionality and then create sub classes from this base class but if I then try to use addEventListener on the subclass instance I get the error:

TypeError: _subClass.addEventListener is not a function

The constructors of my classes look like this:

var BaseClass = function(id)
{
    _instance = this;
    _id = id;
    createjs.EventDispatcher.initialize(BaseClass.prototype);
};

var SubClass = function(id)
{
    BaseClass.call(this, id);
    SubClass.prototype = Object.create(BaseClass.prototype);
    _instance = this;
};

How can I make it work so that SubClass inherits the applied CreateJS event dispatcher functionality from BaseClass? So far it only works if I also apply the event dispatcher in the sub class constructor but that somehow defies the whole purpose of inheritance:

createjs.EventDispatcher.initialize(SubClass.prototype);

Answer 1

You should initialize your prototypes during initialization, not in the constructor. Here is an updated fiddle: http://jsfiddle.net/lannymcnie/qTHb4/

var BaseClass = function(id)
{
    _instance = this;
    _id = id;
};
createjs.EventDispatcher.initialize(BaseClass.prototype);

var SubClass = function(id)
{
    BaseClass.call(this, id);
    _instance = this;
};
SubClass.prototype = BaseClass.prototype;