ESLint v9.6.0 released

Highlights

• ESLint’s default parser espree now supports RegExp duplicate named capturing groups ES2025 syntax when languageOptions.ecmaVersion is set to 2025 or "latest" (default). Please note that the core rules have not yet been updated to support this syntax.
• Backslash (\) can now be used as an escape character in files and ignores patterns, regardless of the operating system. Note that only forward slash (/) is interpreted as a path separator in files and ignores patterns, regardless of the operating system.
• The messages reported by the no-unused-vars rule have been improved to include configured ignore patterns for different kinds of variables.

Features

• e2b16e2 feat: Implement feature flags (#18516) (Nicholas C. Zakas)
• 8824aa1 feat: add ecmaVersion: 2025, parsing duplicate named capturing groups (#18596) (Milos Djermanovic)

Bug Fixes

• 1613e2e fix: Allow escaping characters in config patterns on Windows (#18628) (Milos Djermanovic)
• 21d3766 fix: no-unused-vars include caught errors pattern in report message (#18609) (Kirk Waiblinger)
• d7a7736 fix: improve no-unused-vars message on unused caught errors (#18608) (Kirk Waiblinger)
• f9e95d2 fix: correct locations of invalid /* eslint */ comments (#18593) (Milos Djermanovic)

Documentation

• 13dbecd docs: Limit search to just docs (#18627) (Nicholas C. Zakas)
• 375227f docs: Update getting-started.md - add pnpm to init eslint config (#18599) (Kostiantyn Ochenash)
• 44915bb docs: Update README (GitHub Actions Bot)
• d50db7b docs: Update vscode-eslint info (#18595) (Nicholas C. Zakas)

Chores

• b15ee30 chore: upgrade @eslint/js@9.6.0 (#18632) (Milos Djermanovic)
• d655503 chore: package.json update for @eslint/js release (Jenkins)
• 7c78ad9 refactor: Use language.visitorKeys and check for non-JS SourceCode (#18625) (Nicholas C. Zakas)
• 69ff64e refactor: Return value of applyInlineConfig() (#18623) (Nicholas C. Zakas)
• d2d06f7 refactor: use / separator when adjusting ignorePatterns on Windows (#18613) (Milos Djermanovic)
• 6421973 refactor: fix disable directives for languages with 0-based lines (#18605) (Milos Djermanovic)
• 0a13539 refactor: Allow optional methods for languages (#18604) (Nicholas C. Zakas)
• c7ddee0 chore: make internal-rules not being a package (#18601) (Milos Djermanovic)
• 3379164 chore: remove .eslintrc.js (#18011) (唯然)
• d0c3a32 chore: update knip (with webdriver-io plugin) (#18594) (Lars Kappert)