Missing types for react-dom/client package in compat

[WDeenik]

• Check if updating to the latest Preact version resolves the issue

Describe the bug
When we switched to Preact using compat, we got the following TS error:

Could not find a declaration file for module 'react-dom/client'. I've looked around but although this module does exist and everything functions like it should, I couldn't find type declarations for it.

I solved it for now by adding a custom declarations file with the proper types, but it would be nice if this is included in Preact itself.

To Reproduce

I can't get preact/compat to work in codesandbox unfortunately. Simplest reproduction steps would be to alias Preact in a simple React 18 TS app.

Expected behavior
I would have expected that there would be types for react-dom/client in preact/compat, where I at most would have to add another entry to the "paths" in my tsconfig.json

[developit]

I believe right now the recommended workaround is to alias this. In order to support the types for subpath imports, we need to have separate d.ts files - using a module declaration for react-dom/client assumes preact/compat is being aliased everywhere, which isn't always how it is used.

[bluetech]

I tried the solution given in preactjs/preact-www#1122 but I don't think it solves the actual issue, since compat/client doesn't have a d.ts file, so typescript doesn't know about it even with the alias.

[rschristian]

Strange, seemed to work just fine in my tests.

Can create a new project with npm init preact, toss in that new path alias, and get working types.

[bluetech]

I tried it using npm init preact, installing typescript, adding the aliases, and changing index.tsx to use createRoot (imported as import { createRoot } from 'react-dom/client'). Indeed typescript doesn't complain however the createRoot function has type any. Do you see it properly typed?

[rschristian]

Whoops, indeed.

Oddly, when I go to import either, the types will be sorta inferred (i.e., createRoot: (c: any, o: any) => any), but when I go to use it, it is a bare any (createRoot: any). I must've glanced at this and thought all was good.