[Feature]: Export MockedObject & similar utility types?

[JoshuaKGoldberg]

🚀 Feature Proposal

Could TypeScript types such as MockedObject please be exported from some package that consumers would have access to while using the @jest/globals package?

Motivation

It'd be convenient for declaring types of objects that contain mocks. Right now there's now easy way to declare in the type system that an object is a MockedObject<T> for any T object type.

Example

In typescript-eslint/tslint-to-eslint-config#1458 I'm trying to get the TypeScript types to work for a createStubWritableStream function that returns a mocked version of a NodeJS.WritableStream. Here's a minimum reproduction in the TypeScript playground.

Pitch

MockedObject isn't exported in any way I can find -nor documented on the website-. There's no way to declare the return type of createStubWritableStream -or variables that store that value type- to be MockedObject<NodeJS.WritableStream>.

Even if I'm using jest.fn() and/or the types wrong, being able to refer to MockedObject<...> is quite useful for debugging type system woes such as this one.

[mrazauskas]

Did you check these from jest-mock:

https://github.com/facebook/jest/blob/49393d01cdda7dfe75718aa1a6586210fa197c72/packages/jest-mock/src/index.ts#L77-L87

Documentation is missing, but seems to be exposed. Or these aren’t exactly what you need?

[JoshuaKGoldberg]

I think those are exactly what I need, yes and thank you! +1 to documentation existing -- I'd assumed jest-mock was an internal package not meant for consumers.

[mrazauskas]

Current I work on #12727. It will add Mocked utility type to Jest object (similar to jest.Mocked from @types/jest) for those who import {jest} from '@jest/globals'. Documentation will be part of that PR, of course.

[SimenB]

Documenting that all the mock types are available from jest-mock seems reasonable. Not sure putting all of them on jest makes sense, but making sure they are consumable from jest-mock sounds good

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[alesmenzel]

@SimenB From the user's perspective it is very hard to discover what types are available in which internal jest-[whatever] package because you as a user of jest don't even know those packages like jest-mock are installed because they are not a peer dependency, but rather a direct dependency. I would like jest to reexport all TS types in the main jest package so it is easy to look for/import those types rather than scanning through jest's overwhelming number of dependencies.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[mrazauskas]

From #12856 (comment)

#12727 landed recently adding refreshed (see #13123) utility types jest.Mocked, jest.MockedClass, jest.MockedFunction and jest.MockedObject. Will be released with Jest 29. Simply import {jest} from '@jest/globals' and use them. Docs: https://jestjs.io/docs/next/mock-function-api#jestmockedsource

@JoshuaKGoldberg @alesmenzel Just wanted to ask – are there any other types you would find useful? (Or any use cases where typing becomes cumbersome?)

[JoshuaKGoldberg]

This looks like all I'd need for now, thank you very much!

[github-actions]

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