How do I expose classes and their methods in this particular typescript declaration?

I'm trying to get a handle on writing Typescript definitions for various libraries and can't seem to figure out how to do it for a particular NPM module.

The module in question is bbcode-to-react

The final dist JS is such a mess from packing/builds that I can't seem to work it out.

I would need to expose the Parser and Tag classes and some of their methods so that I can extend the Tag class and register it with the parser using it's registerTag(string, Tag) method.

via Strawberry Bunny