> I would suggest we send an object ...

Are you sure? Please check `notifyObservers()` [documentation][1] again! ;)

    void notifyObservers(
      in nsISupports aSubject,
      in string aTopic,
      in wstring someData 
    );

I could use `JSON.parse()` here, if you really want to pass an object.

[1]: https://developer.mozilla.org/docs/XPCOM_Interface_Reference/nsIObserverService#notifyObservers%28%29