What:

This adds a types export for the package, using jest 28's recommended way to augment expect: https://jestjs.io/blog/2022/04/25/jest-28#expect

This might be a breaking change for users on jest 27 or below and using typescript.

Why:

I want to update @storybook/expect to use jest 28, but currently, due to the typescript changes in jest 28, the types from jest-dom are broken.

I took a look at a few issues in this repo, including #426, #314, and #457, and I think I'm not alone in having issues with jest 28 and types.

How:

This augments the expect package, using the types from definitely-typed (instead of trying to move them into this package for now).

Checklist:

• Documentation
• Tests
• Updated Type Definitions
• Ready to be merged
  

I'm opening this up for discussion. I tested this approach out in my own project, and it works correctly when I also add an import '@testing-library/jest-dom'; statement in @storybook/expect. I wanted to see if the maintainers of this repo would consider making a breaking change to support jest 28+, or if you have any other ideas of how to handle types for projects which aren't using jest globals, but are using expect directly.

Note: I also had to tweak the eslint config a little bit, so that the @typescript-eslint rules stopped failing and would let the precommit hook succeed. Buuuut, it looks like that's failing CI. Maybe a maintainer can get main working correctly with eslint, and I can rebase this on top?