Publishing a lib as JS with .d.ts type files gives you JS compatibility and TS types for using the lib, but no TS source so no types inside.

I’ve seen people want to publish TS libs but there are issues: TS will type check the libs as well as your project. You can’t tell it to stop just because it’s going inside node modules. And the app may have tighter settings than the library and you will get type errors if your configs were setup differently. It would be interesting to standardize publishing real typescript libs but I haven’t seen it. Maybe deno tried? I haven’t looked.