ESLint v9.30.0 released

Highlights

basePath property in config objects

Config objects can now include the new basePath property to specify the path to a subdirectory to which the config object should apply to. If a config object has a basePath property, patterns specified in files and ignores are evaluated relative to the subdirectory represented by basePath. This makes it easier to write config objects that target a particular directory inside your project.

// eslint.config.js
import { defineConfig } from "eslint/config";
import js from "@eslint/js";

export default defineConfig([
    {
        basePath: "packages/hello-base-path",
        plugins: { js },
        extends: ["js/recommended"],
        ignores: ["coverage/**", "dist/**"],
    },
]);

You can read more about base paths in config objects in the documentation.

Stable feature flag v10_config_lookup_from_file

With the addition of the basePath property in config objects, the experimental configuration file resolution introduced in ESLint v9.12.0 has been finalized. It will become the default behavior in the next major release of ESLint. Accordingly, the feature flag unstable_config_lookup_from_file has been renamed to v10_config_lookup_from_file. The old flag name still works, so if you are already using unstable_config_lookup_from_file in your setup, you don’t need to take any action.

New allowSeparateTypeImports option in no-duplicate-imports

With the new option allowSeparateTypeImports, the no-duplicate-imports rule can now be configured to treat import and import type as separate usages, even if they specify the same module.

/*eslint no-duplicate-imports: ["error", { "allowSeparateTypeImports": false }]*/

import { someValue } from 'module';
import type { SomeType } from 'module';

Other notable changes

• The SourceCode method getIndexFromLoc now throws an error if the argument specifies a negative value for the column property.

Features

• 52a5fca feat: Support basePath property in config objects (#19879) (Milos Djermanovic)
• 4ab4482 feat: add allowSeparateTypeImports option to no-duplicate-imports (#19872) (sethamus)
• b8a7e7a feat: throw error when column is negative in getIndexFromLoc (#19831) (루밀LuMir)

Bug Fixes

• 6a0f164 fix: handle null type loc in getIndexFromLoc method (#19862) (루밀LuMir)
• 3fbcd70 fix: update error message for no-restricted-properties (#19855) (Tanuj Kanti)
• 7ef4cf7 fix: remove unnecessary semicolon from fixes (#19857) (Francesco Trotta)
• 7dabc38 fix: use process.version in --env-info (#19865) (TKDev7)

Documentation

• 8662ed1 docs: adopt eslint-stylistic sub packages related changes (#19887) (ntnyq)
• 20158b0 docs: typo in comment for unused variables handling (#19870) (leopardracer)
• ebfb5b4 docs: Fixed Typo in configuration-files.md (#19873) (0-20)
• 4112fd0 docs: clarify that boolean is still allowed for rule meta.deprecated (#19866) (Bryan Mishkin)

Chores

• 2b6491c chore: upgrade to @eslint/js@9.30.0 (#19889) (Francesco Trotta)
• 5a5d526 chore: package.json update for @eslint/js release (Jenkins)
• eaf8a41 chore: Correct typos in linter tests (#19878) (kilavvy)