Describe the feature you'd like:

Title says it all. I feel like TypeScript has reached a level of adoption where we shouldn't be scared of losing contributors by using it instead of JavaScript.

I believe other @testing-library packages are considering or currently being converted, if they aren't already TS.

Suggested implementation:

We currently have type definitions in DefinitelyTyped which can be used as the basis of the types.

I think we can aim to have a straight cut over to a new codebase rather than a progressive migration as there are not that many files to consider.

I think we should look at using TSDX for the tooling unless anyone has other ideas or suggestions in this space.

Describe alternatives you've considered:

N/A

Teachability, Documentation, Adoption, Migration Strategy:

This package should also become the source of truth for the type definitions and the DefinitelyTyped version should be deprecated. I'm not sure what the process if to do that if there is one.

Other than that I don't think there are any particular considerations to be made for this.