@testing-library/react has transitive deps to @types/react: *

[jackyef]

• react-testing-library version: 9.3.0

What you did:

We have a react library written in typescript that has exact devDependency to @types/react: "16.9.9". @testing-library/react` is also one of the library devDependencies.

What happened:

When installing all devDependencies (including bundler and babel stuffs) so we can build our library, we ended up with 2 different @types/react, because @testing-library/react has deps to @types/react: *, which resolves to a newer version of @types/react.

Because there are 2 different @types/react, tsc will fail when trying to build our package.

Suggested solution:

Set @types/* packages as devDependencies of @testing-library/react

[kentcdodds]

Hi @jackyef,

Thanks for the issue. React Testing Library does not include @types/react in the package.json at all. I don't think that this package is the culprit to your problems. Good luck!

[jackyef]

@kentcdodds Hi, you're right, I was incorrect in saying it was one of @testing-library/react deps, it was actually one of the transitive dependencies!

It goes like this:

1. @testing-library/react has deps to @types/testing-library__react
2. @types/testing-library__react has deps to @types/react-dom,
3. @types/react-dom has deps to @types/react

> yarn why @types/react
yarn why v1.16.0
[1/4] Why do we have the module "@types/react"...?
[2/4] Initialising dependency graph...
[3/4] Finding dependency...
[4/4] Calculating file sizes...
=> Found "@types/[email protected]"
info Reasons this module exists
   - "@testing-library#react#@types#testing-library__react#@types#react-dom" depends on it
   - Hoisted from "@testing-library#react#@types#testing-library__react#@types#react-dom#@types#react"
Done in 0.15s.

Would there be a problem if we make @types/testing-library__react as a devDependencies instead of dependencies of @testing-library/react?

[kentcdodds]

Including them as dependencies is an intentional choice (read more: #437).

Is there a reason you're not using the latest version of the react types? I think you probably should...

[jackyef]

Ah, I see! That was interesting to read the perspective of everyone involved :)

For my specific case, yes, it would be totally fine to just use the latest version of @types/react.

For what it's worth, some people might be using an older version of react and therefore use old version @types/react to match. The amount of that specific case is probably really small though.

I understand shipping @types/testing-library__react along with @testing-library/react is intentional, but what about having @types/react as deps of @types/testing-library__react? Could that be made a devDep? People should still get the typings for @testing-library/react automatically.

[eps1lon]

@jackyef That is a long standing issue with how types are published from DefinitelyTyped. TL;DR: @types/react: "*" is a hack for optional peer dependencies.

Most package managers do support these now so we can revisit this over at DefinitelyTyped. In the meantime I suggest you get familiar with manually editing your lockfile. For yarn.lock you can post every entry for @types/react here and I can patch it so that you have a single, older version of @types/react. For npm I can't help you unfortunately.

[jackyef]

We have fixed this issue on our end. My reason for continuing the discussion here is mostly just to satisfy my curiosity 😃

I'll be looking forward to hear the updates over at DefinitelyTyped then, thanks!