feature request: add ignore options for `import/no-duplicates`

[JounQin]

When using TypeScript with date-fns, it only has one bundled typings.d.ts, so eslint-import-resolver-ts will resolve all modules to it.

But they are not all exported from date-fns, what means date-fns and date-fns/locale are different.

So we should allow this case by whitelist.

[ljharb]

This seems like an inherent flaw in resolving a module to a d.ts file that might represent multiple files. I don’t think forcing an allowlist is an elegant solution; I’d prefer to find a better one.

[JounQin]

If we do have a better one, that will be greater.

[JounQin]

@ljharb Any news on this. If we don't have a better solution, an option for whitelist maybe considered?

[ljharb]

Rereading the OP, it kind of seems like it’s just a bug in date-fns’ typings file?

[JounQin]

Why do you think it's a bug of date-fns? It's valid usage of .d.ts files.

[ljharb]

But they are not all exported from date-fns, what means date-fns and date-fns/locale are different.

[JounQin]

.d.ts are fine to be declared in one file for multiple sources. It valid and TypeScript itself doesn't complain. So it's just a choice.

[ljharb]

If the types in date-fns are correct, then eslint-import-resolver-ts (eslint-import-resolver-typescript is the one i recommend, incidentally) should be resolving them properly.

I'm still confused what the issue is. Are you saying that because date-fns and date-fns/locale resolve to the same type file, they're considered as duplicate imports?

[JounQin]

import * from 'date-fns'
import * from 'date-fns/locale'

The above import statements both resolves a same typings.d.ts which include

declare module 'date-fns' {
  // ...
}

declare module 'date-fns/locale' {
  // ...
}

[JounQin]

Are you saying that because date-fns and date-fns/locale resolve to the same type file, they're considered as duplicate imports?

Yes, that's the point.

[ljharb]

It doesn’t seem right to me that they should resolve to the location of their types, so that seems like something that should be fixed in the resolver.

[JounQin]

What's the problem of the resolver? We may import types from the pkg, there is no types in .js sources, so .d.ts files are preferred.

[ljharb]

Yeah, i can see the difficulty. I’m not sure how we’d solve this properly. An exclude list seems like a workaround.

[JounQin]

An exclude list seems like a workaround.

So is this accepted? I can raise a PR if so.