Configure file extensions in .eslintrc

AFAICT, this is not supported at the moment. Example:

1. You have a Node app
2. Your React components use the .jsx extension.
3. You have one .eslintrc at the root for Node, and nested .eslintrc with jsx: true.

It seems you have to run eslint . --ext .js,.jsx which is ok, but my intent is really to scope parsing of .jsx files to the subtree that contains them. That’s why I thought rc-level config might make sense.

[not-an-aardvark]

@ljharb

It would still be ideal to replicate the --ext option in config files; every CLI option and config option should generally be symmetric.

Making CLI options and config options symmetric is not really a goal at the moment; there are some CLI options like --fix which intentionally require user opt-in.

For more discussion on specifying extensions without command-line flags, see https://github.com/eslint/eslint/issues/8920.

For more discussion on statically declaring command-line flags in general, see https://github.com/eslint/eslint/issues/9484.

[not-an-aardvark]

This is now possible (see the documentation here).

{
  "overrides": {
    "files": "your/globs/**/*.js",
    "rules": {
      "some-rule": "off"
    }
  }
}