Should i always create index.ts(public api) file in the shared/api directory?

[stegano]

Should i always create an index.ts(public api) file in the shared/api directory? In my project, I met the message below from Steiger linter

┌ src/@fsd/shared/api
✘ This segment is missing a public API.
✔ Auto-fixable
│
└ fsd/public-api

My project has directory bellow

@fsd
 - (something)
 - ui
   - sometihng/
     - somethingUi1
     - somethingUi2
     - index.ts # <- It's allowed by Steiger linter
 - api
   - something/
     - somethingApi1
     - index.ts # <- but, It's disallowed by Steiger linter

I'm confused this rule, because I saw this document(https://feature-sliced.design/en/docs/reference/public-api#large-bundles) but Steiger displays the message above. does this rule affect only ui and lib segments?

Which is wrong, my project directoy or Steiger lint?
Can anybody explain about this rule to me please?

[illright]

Yes, indeed, that exception only really exists for ui and lib, not for api. Is there a reason why you don't want to have a common index.ts file in shared/api for all subfolders?

[stegano]

Hi @illright

Thank you for your response.

I expected that the subfolders(modules) inside the shared segment would follow the same rules. Having exceptional rules for some folders might be confusing for people.

Could you explain why the api or other segments(excluding UI or lib) subfolders cannot have their own public API (index.ts) for each module

If i'm miss understanding, please let me know
Thanks

[stegano]

ping @illright
I'm looking forward to your response 🙏

[illright]

The reason that the UI and lib folders are excluded from this rule is that they are likely to contain bundle-heavy code that isn't needed everywhere. For example, you might have a complicated DataTable component in your UI kit that you only want included on the pages that actually use it.

This is not the case with the API client. Usually, the API client is a pretty thin wrapper so bundle size isn't as pressing of an issue. The main benefit of the public API is to establish a predictable, controlled entrypoint, so allowing multiple public APIs goes against this goal. We allow it for UI and lib only because of bundle size concerns

[stegano]

Thanks for your answer 👍