Add vitest

[jawj]

Add vitest example test and add GitHub action to run it.

Relatedly, add .prettierrc and a GitHub Action to check TypeScript types.

[jawj]

I've added GitHub Actions for a dummy test and also a TypeScript type check.

We currently have 3 separate workflows (.yml files) that are mostly the same. We could alternatively have these be three jobs within the same workflow, or even three bun run ... commands within the same job (which would save a bunch of duplicated bun installs). But my feeling from other repos is that we prefer to do one thing per workflow?

[pffigueiredo]

I think a lot of the common setup like install deps should be a single action that we import, something like this: https://github.com/JoshuaKGoldberg/create-typescript-app/blob/main/.github/actions/prepare/action.yml

Let's forget about this for now 👍

[pffigueiredo]

I think we should do both type and format checking in the same workflow, they are usually very coupled with each other - maybe call it lint

[amitdahan]

What do we do to actually update the lockfile since we use bun install? I don't expect it to update the package-lock.json I think, AFAIK it only reads it to seed the resolution tree but then keeps using its own binary lockfile thing.

[jawj]

Yes, after looking at https://bun.sh/docs/cli/install#production-mode it seems --frozen-lockfile isn't going to do anything for us since we don't include a Bun lockfile (bun.lockb) in the repo?

[pffigueiredo]

LGTM! 🚀