Basically it solves three fundamental TypeScript frustrations:

1. TypeScript's compiler (`tsc`) can't produce valid ESM output

2. Using bundlers to fix ESM output creates misalignment with type definitions

3. We should be able to use `.ts` extensions in our source files since that's what they actually are!

It's a simple post-build tool that:

- Transforms `tsc` output into valid ESM by adding proper extensions

- Ensures your type definitions match your actual code structure

After 8+ years of open TypeScript issues, I got tired of waiting for a proper solution.

GitHub: https://github.com/2BAD/tsfix

P.S. Did you know none of the top 100 TypeScript projects on GitHub use `tsc` for production builds?