[franky47]

I get their stance on TypeScript "exported types must be explicit and not use inference", but I feel like this is going to cause a lot of friction in adoption.

[lucacasonato]

1. You can bypass slow types checks during publishing. You will just get a lower JSR score.

2. TypeScript is shipping features in the next release (TS 5.5) has quick-fixes in the editor to make it super easy to add explicit types :) The TS feature is called `isolatedDeclarations`

[dragomirtitian]

I would just like to add some of my findings around the developer friction with isolated declarations.

The whole reason isolated declarations is taking so long is because we also worry about making the requirements of this too onerous. To this end with isolated declarations, you do have to specify most types, but not all. For expression where we can reasonably infer the type from local context, we do so.

This should ease some of the developer friction. Not all of it. Some things will not be inferrable, but things like primitive types, object literals, tuples will be so it should make it easier.

We also worked on a code fixer that adds explicit type annotations where this new flag would raise an error, again to help people migrate if they choose to do so.

[dsherret]

To be clear for people reading wondering what this is about, this is only a hard recommendation for the public API types. The reason for it, is by adding explicit types to the boundary of your package, the package becomes way faster for users to type check because every user's machine doesn't need to do all the inference work and type check internal types or packages not related to the types. Additionally, it makes the published code more resilient to changes to TypeScript's inference in the future because it's not doing inference. It also becomes way easier to generate documentation for the package (also, the ability to generate .d.ts or bundled .d.ts files without a type checker becomes easier).

Right now, the publish command errors and asks you to fix the issues or bypass it entirely via `--allow-slow-types`. In the future there will be a `--fix` flag to write the explicit types for you.