Create-react-app: Support index.web.js entry file

[Hermanya]

This is similar to "Support index.jsx entry file #3052".
I'm playing around with react-primitives and naturally I have multiple entry points into my app. After reading the reasons why #3052 was closed, I still think that index.web.js is a valid use case. Thank you for consideration.

[viankakrisna]

https://github.com/facebook/create-react-app/issues/3052#issuecomment-356114916 suggest that if it's easy, they are happy to take a PR.

I think the one way to do it without fiddling with webpack config is to let node's own module resolution takes care of this.

https://github.com/facebook/create-react-app/blob/next/packages/react-scripts/config/paths.js#L56 -> instead of hard-coding src/index.js we can move it to just src, and the user can create a package.json there with main property pointed to any file the user like.

[Hermanya]

IIRC node's module resolution does not handle index.web.js. And I don't think package.json main would work either, because the use case is when you have multiple main entry points for different platforms such as index.web.js, index.ios.js, index.android.js and so on.
I think the most reasonable solution is to modify the line that you referenced, check if src/index.web.js exists, and otherwise proceed with src/index.js
Truth be told I'm surprised that package.json main is not supported, so maybe check that too.

[viankakrisna]

that would also work. and we can just use paths.appSrc variable in the webpack configs. I think there's a bigger reason why they don't go supporting node resolution though I'm not sure.

I'm curious about how you set up your multi-platform app with CRA though, do you have an example of how you do that?

[Hermanya]

Sorry for the delay. Here is my setup.
As for supporting node resolution, I think it's because there was no need to support index.json and index.node extensions.

[brunolemos]

This is on master since #4837.

These are now accepted as an entry point:

• index.js
• index.jsx
• index.mjs
• index.ts
• index.tsx
• index.web.js
• index.web.jsx
• index.web.mjs
• index.web.ts
• index.web.tsx

You can close this issue. :)