I dont know how to use this._super() in canJS

CanJS
2

You mentioned controllers, so I will assume you are referring to can.Control, with which you could do something like this:

var Parent = can.Control.extend({
  init(el, opts) {
    this.foo = 'bar';
  }
});

var Child = Parent.extend({
  init(el, opts) {
    // call the parent to set `foo='bar'`
    this._super(el, opts);
    // more logic here
  }
});

If you are using Components, the events object will be used to create a control, but _super() doesn’t really apply because you aren’t inheriting from another control (besides the internal ComponentControl).

If you are referring to a Component’s ViewModel as the controller, you can do the same type of thing with a Map constructor or any Construct.