ESLint v9.0.0-beta.1 released

Highlights

This is a summary of the major changes you need to know about for this version of ESLint.

Installing

Since this is a pre-release version, you will not automatically be upgraded by npm. You must specify the next tag when installing:

npm i eslint@next --save-dev

You can also specify the version directly:

npm i eslint@9.0.0-beta.1 --save-dev

Migration Guide

As there are a lot of changes, we’ve created a migration guide describing the breaking changes in great detail along with the steps you should take to address them. We expect that most users should be able to upgrade without any build changes, but the migration guide should be a useful resource if you encounter problems.

Features

• 74124c2 feat: add suggestions to use-isnan in indexOf & lastIndexOf calls (#18063) (StyleShit)

Bug Fixes

• 0cb4914 fix: validate options when comment with just severity enables rule (#18133) (Milos Djermanovic)

Documentation

• 5fe095c docs: show v8.57.0 as latest version in dropdown (#18142) (Milos Djermanovic)
• 7db5bb2 docs: Show prerelease version in dropdown (#18135) (Nicholas C. Zakas)
• 73a5f06 docs: Update README (GitHub Actions Bot)
• f95cd27 docs: Disallow multiple rule configuration comments in the same example (#18116) (Milos Djermanovic)
• d8068ec docs: Update link for schema examples (#18112) (Svetlana)

Build Related

• c9f2f33 build: changelog update for 8.57.0 (#18144) (Milos Djermanovic)

Chores

• 32ffdd1 chore: upgrade @eslint/js@9.0.0-beta.1 (#18146) (Milos Djermanovic)
• e41425b chore: package.json update for @eslint/js release (Jenkins)
• bb3b9c6 chore: upgrade @eslint/eslintrc@3.0.2 (#18145) (Milos Djermanovic)
• e462524 chore: upgrade eslint-release@3.2.2 (#18138) (Milos Djermanovic)
• 8e13a6b chore: fix spelling mistake in README.md (#18128) (Will Eastcott)
• 66f52e2 chore: remove unused tools rule-types.json, update-rule-types.js (#18125) (Josh Goldberg ✨)
• bf0c7ef ci: fix sync-labels value of pr-labeler (#18124) (Tanuj Kanti)
• cace6d0 ci: add PR labeler action (#18109) (Nitin Kumar)
• 1a65d3e chore: export base config from eslint-config-eslint (#18119) (Milos Djermanovic)
• 9aa4df3 refactor: remove globals dependency (#18115) (Milos Djermanovic)