When dealing with binary packages I have to do stuff like iterating over an object to see what it exposes. I guess typings (if one exist) help a lot there. But for open source code you can just look in the source. Looking at other peoples source code is the best way to learn, so don't let TypeScript take that away for you. The projects with non-existing documentation is often the ones most easy to use. Maybe because the source code is so easy to understand that no documentation is needed :P