Very promising though, despite the exports being broken. We're so close!

At the risk of derailing a PR conversation, can I ask why the open-wc source just doesn't use TypeScript directly?

woop woop new version at microsoft/TypeScript#32372 (comment) and it seems to work perfectly now 🎉

@benjamind could you verify if the types are now fully helpful? 🤗

I can verify that I pulled in the @openwc/testing-helpers package from this branch and it compiled against my typescript project without issue! Types appear to be strongly applied, and I managed to remove all of my hand crafted .d.ts files for that package.

I then added @openwc/semantic-dom-diff to the compilation and got some usable-ish files. Since its used as a chai plugin i think we need some additional types there to correctly expose its functionality on the Chai Assertion namespace, but I think thats just a thing thats lacking from the jsdoc and not an issue with this tsc generation.

Overall I think this is an excellent approach (second only to native Typescript which would be my preference), but this gives us very usable output for Typescript and I think will mean we can after some more testing remove the allowJs approach from our recommended typing configuration which is a great win for Typescript users.

@justinfagnani we're not doing that because we want to maintain a low barrier for people to contribute to the project.

@LarsDenBakker I understand that concern, but from my experience as a maintainer of a lot of TypeScript-based projects I've found that TS has possibly more often than not made it easier for contributors because of the excellent tooling that helps newcomers navigate the codebase and catch errors early. We've seen comments like "that was easier/more helpful than I expected". I'm personally hesitant to contribute to non-TS projects these days :)

closed in favor of #697