[file-extension-in-import] Dir imports resolve to `package/dir.js` instead of `package/dir/index.js`

[Sarabadu]

Environment

Node version: 20
npm version: 10.1.0
ESLint version: 8.51.0
eslint-plugin-n version: 16.2.0
Operating System: macos

What rule do you want to report?

file-extension-in-import

Link to Minimal Reproducible Example

https://eslint-online-playground.netlify.app/#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

What did you expect to happen?

I was expecting to auto fix this issues with file-extension-in-import plugin instead of being flagged as error from n/no-missing-import

import { Output } from '@pulumi/pulumi/output'; // this should be fixable as '@pulumi/pulumi/output.js'
import {listWebAppHostKeysOutput} from '@pulumi/azure-native/web/v20220901'; // this should be fixable as '@pulumi/azure-native/web/v20220901/index.js'

migrating to node 20 those imports are failling with:

Error [ERR_UNSUPPORTED_DIR_IMPORT]: Directory import '/.../node_modules/@pulumi/azure-native/web/v20220901' is not supported resolving ES modules imported from /.../someFile.js
    Did you mean to import @pulumi/azure-native/web/v20220901/index.js?

Would be nice to use file-extension-in-import (maybe with some additional configs) to auto fix those

Participation

• I am willing to submit a pull request for this issue.

Additional comments

No response

[scagood]

Thank you for the report!

This looks to be because the package does not have an "exports" in it's package.json

I suppose that we need to detect if the package.json has exports defined or not, then change the behaviour accordingly 🤔

I am not sure if that should be in file-extension-in-import or in no-missing-import though. This is because the second example does not just add an extension, it adds a whole file to the directory.

[Sarabadu]

yes my first though was on adding "/index.js" in the tryExtensions config, but you are right, maybe we need a no-dir-imports separated rule, with auto fix?

[scagood]

I think that that is a good rule idea, but I don't think it'd work in this case as things get a lot more complicated when you go into modules.

It'd work well for relative / absolute imports, but in the case of modules you need to check for:

• exports in the package json
• symlinked packages (eg pnpm) and compressed packages with a loader (eg yarn v3 pnp)
• additional file types (eg .d.ts, .node, and .js)

---

In my company we created a new rule called custom/require-resolve which (as the name implies) called require.resolve(import) then resolved the path relative to the file.
But we explicitly removed all modules from that.

[scagood]

This looks to have been resolved in #139

For now, you can use the beta version (npm i eslint-plugin-n@next) if you don't want to wait for the next release (#158)