I'm using the v6 and TS typings are a bit broken. I think migrating the source code to TypeScript could help in many aspects:

- Immediately catch type errors;

- More signal, less noise (because a lot of duck typing won't be needed anymore);

- Self-documenting nature of static typing will make it a lot easier for other people to contribute;

- Less chances of accidentally breaking things during refactorings.

Those are only some of the benefits. There are other less important ones like better IDE experience and not needing to keep separate, unsynced d.ts files. If you think it's a good idea, I may be able to help with PRs.