Deprecate import-index rule

[fisker]

No description provided.

[kachkaev]

@fisker WDYT of a rule that bans index.{js,ts}{,x} files? I am currently using canonical/filename-no-index, but it’d be much cooler to have this rule in unicorn too!

I know that it's better to discuss such things in a new issue – this is just a quick sense-check.

[fisker]

I don't know, I alway use index.js like this https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/rules/selectors/index.js

[fisker]

Maybe only allow re-export in index.js?

[kachkaev]

I used to use index.js to re-export stuff for a while. This was my typical dev flow:

1. Create foo.js
2. Add code
3. Realise that foo.js is too big
4. Replace the file with foo/index.js which re-exports foo/bar.js, foo/baz.js, etc.

The problem with this approach is that the last step is quite tedious. It’s not only necessary to delete the original file, but also to think about filenames in the subfolder. It is not always easy to come up with nice mini-groups to avoid actual code in foo/index.js.

Another problem with foo/index.js is that it can’t be imported the same way as foo.js, unless we rely on the Node.js resolution mechanism. Pure ESM modules don’t support import { foo } from "./foo"; — it has to be either import { foo } from "./foo.js"; or import { foo } from "./foo/index.js";.

So I’ve decided to ban index.js completely and here is what I do now:

1. Create foo.js
2. Add code
3. Realise that foo.js is too big
4. Create foo folder and place foo/bar.js into it.
5. Add import { bar } from "./foo/bar.js" in foo.js. Keep existing code in foo.js as long as I’m happy with the file size.

Thus, foo.js works as the stable ‘entry point’ for foo and foo folder contains ‘private’ stuff that can only be imported from foo.js. Other files can only import from ./foo.js (as if it’s a local mini-npm library), but they must never look into files like ./foo/bar.js. That would be like calling a private method of a class.

What’s cool is that an upgrade from foo.js into foo.js + foo/*.* is no longer a ‘revolution’. The transition feels very natural and does not stand on my way.

This approach is inspired by https://github.com/benawad/destiny — see this youtube talk. If you want to check out an example file structure, here are a couple of public projects I’ve got using it:

• https://github.com/kachkaev/njt (pages)
• https://github.com/kachkaev/tooling-for-how-old-is-this-house (pages, shared, pages/shared, pages/poster.page/poster/shared)

All this is still experimental. Curious to hear your thoughts!