Move package to ESM + ESLint 9

[ahkhanjani]

In this PR I have:

• Made the npm package to use ESM internally (to support ESLint 9).
• Updated ESLint dependencies to latest and added some rules to be more strict. Removing the outdated no-restricted-imports plugin caught a problem on its own.
• Fixed the lint errors.

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Name	Status	Preview	Comments	Updated (UTC)
react-resizable-panels	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Nov 18, 2024 10:51pm

[ahkhanjani]

@bvaughn Is this PR ok with you?

E2E tests are failing because of commonjs tests. So how about we drop cjs entirely and release a v3? I can do it if it's ok with you

[bvaughn]

I appreciate the effort spent on this PR. It's kind of a noisy change though, and (as it is) I think it could cause a couple of small regressions (commented). I'm not sure if I want to move forward with it.

[ahkhanjani]

@bvaughn What should we do about the cjs issue? Should we drop cjs support and go for a v3?

[bvaughn]

Hmm. I don't think there's a strong reason to drop CJS support, unless it would in some way dramatically improve the source code/maintainence?

[ahkhanjani]

Hmm. I don't think there's a strong reason to drop CJS support, unless it would in some way dramatically improve the source code/maintainence?

My knowledge on the topic of CJS/ESM is limited but since the ecosystem has been moving on from CJS and been dropping support since Node 16 got deprecated (I'm not sure why but that's what I've witnessed), the project itself has to use ESM ("type": "module" in package.json) to support the latest releases and be up-to-date. So as you can see because I've switched to ESM internally to support ESLint 9, the E2E tests related to CJS are failing. Maybe we can make them work by adding more complexity but that would make the project harder to maintain. So my answer is yes, it will improve the maintenance by a lot.

Also I think people who use React mostly use ESM and the ones who aren't up to date will be ok with v2.

[ahkhanjani]

Hey @bvaughn. I fixed an import issue I had made and now one test is strangely failing:

PanelGroup › invariants › should throw if default size is less than 0 or greater than 100

Expected substring: "Invalid layout"                                                                                                               
Received message:   ""

The test itself makes sense but I couldn't find anywhere in the code that throws this exception. Why wasn't the error failing before?

[ahkhanjani]

I'm also getting warnings saying import { act } from "react-dom/test-utils" is deprecated in favor of import { act } from "react". Is it ok if I replaced those? No issues were caused when I tested it.

One other thing I'm seeing is the exported createRef from vendor/react.ts is only being used in tests and not in the code so it appears in the bundle without being used. Should I change the imports in tests to react directly and remove the export from vendor?

[bvaughn]

Going to close this PR in favor of #474 and #476 but I appreciate the work you did here 🙇🏼