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• I have searched for related issues and found none that match my proposal.
• I have searched the current rule list and found no rules that match my proposal.
• I have read the FAQ and my problem is not listed.

Relevant Package

parser

My proposal is suitable for this project

• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Description

Re-filing #251 now that ESLint's flat config is stable: asking users to manually set tsconfigRootDir is a mild config pain:

• It's an extra line of code plumbing to memorize a need for
• Its default value is >99% of the time just the current file's directory...
• ...which has some nuance in how to retrieve (CJS/ESM; import.meta.dirname Node.js support)

#251 was closed as noted in #251 (comment) because ESLint doesn't tell parsers the eslintrc path(s). But, now that we're on flat config, maybe there's a way to get the single flat config file / directory. That would be ideal IMO.

If we could infer tsconfigRootDir then https://typescript-eslint.io/getting-started/typed-linting would be simplified by a line:

 import eslint from '@eslint/js';
 import tseslint from 'typescript-eslint';
 
 export default tseslint.config(
   eslint.configs.recommended,
   tseslint.configs.recommendedTypeChecked,
   {
     languageOptions: {
       parserOptions: {
         projectService: true,
-        tsconfigRootDir: import.meta.dirname,
       },
     },
   },
 );

...and #10507 would be unblocked, which would allow simplifying that config in the next major version to the much cleaner:

 import eslint from '@eslint/js';
 import tseslint from 'typescript-eslint';
 
 export default tseslint.config(
   eslint.configs.recommended,
   tseslint.configs.recommendedTypeChecked,
-  {
-    languageOptions: {
-      parserOptions: {
-        projectService: true,
-      },
-    },
-  },
 );

✨.

Additional Info

Investigation needed:

1. Is there an ESLint API / something provided to parsers that would help with this?
2. If not, can we file an issue on ESLint core asking for it?

💖