ESLint v3.0.0 released

As breaking changes can cause problems for some users, we’ve created a migration guide describing the changes in great detail along with the steps you should take to address them. Not all ESLint users will be affected by the changes, however, we recommend everyone read the migration thoroughly.

Highlights

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

Requires Node.js 4 or higher

ESLint v3.0.0 now requires Node.js 4 or higher. Going forward, our plan is always to support the LTS version of Node.js and periodically end-of-life support for older Node.js versions. As both Node.js v0.10 and v0.12 will be out of maintenance mode at the end of 2016, we hope that this change won’t affect too many users.

If you still need ESLint to run on Node.js < 4, then we recommend staying with ESLint v2.13.1 until you are ready to upgrade your Node.js version.

eslint:recommended Update

We’ve added some new rules to eslint:recommended that we believe are important for all users. You can read more about these changes in the migration guide.

Configuration is Now Required

One of the most confusing aspects of ESLint for new users has been that ESLint doesn’t do anything unless you provide a configuration. While this is good from a configurability perspective (we don’t force any configuration on you), we still get a lot of reports from new users who don’t understand what’s happening. As such, we decided to make configuration a requirement for ESLint and will not longer run if no configuration is present. Instead, ESLint will output an error when it can’t find a configuration file and no configuration information is provided on the command line. More information is available in the migration guide.

Breaking Changes

• dc5b78b Breaking: Add require-yield rule to eslint:recommended (fixes #6550) (#6554) (Gyandeep Singh)
• e0d4b19 Breaking: Error thrown/printed if no config found (fixes #5987) (#6538) (Kevin Partington)
• fa05119 Breaking: Update eslint:recommended (fixes #6403) (#6509) (Nicholas C. Zakas)
• 58542e4 Breaking: Drop support for node < 4 (fixes #4483) (#6401) (alberto)
• f50657e Breaking: use default for complexity in eslint:recommended (fixes #6021) (#6410) (alberto)

Enhancements

• e2b2030 Update: Check RegExp strings for no-regex-spaces (fixes #3586) (#6379) (Jackson Ray Hamilton)
• 397e51b Update: Implement outerIIFEBody for indent rule (fixes #6259) (#6382) (David Shepherd)
• 1290657 Update: no-unused-vars ignores read it modifies itself (fixes #6348) (#6535) (Toru Nagashima)
• 0a7936d Update: Add fixer for prefer-const (fixes #6448) (#6486) (Nick Heiner)
• e06a5b5 Update: Add fixer for arrow-parens (fixes #4766) (#6501) (madmed88)

Bug Fixes

• 7988427 Fix: lib/config.js tests pass if personal config exists (fixes #6559) (#6566) (Kevin Partington)
• d601f6b Fix: Delete cache only when executing on files (fixes #6459) (#6540) (Kai Cataldo)
• 18663d4 Fix: false negative of no-useless-rename (fixes #6502) (#6506) (Toru Nagashima)
• 4343ae8 Fix: false negative of object-shorthand (fixes #6429) (#6434) (Toru Nagashima)
• 3b0ab0d Fix: add warnIgnored flag to CLIEngine.executeOnText (fixes #6302) (#6305) (Robert Levy)
• 5668236 Fix: Allow objectsInObjects exception when destructuring (fixes #6469) (#6470) (Adam Renklint)
• 17ac0ae Fix: strict rule reports a syntax error for ES2016 (fixes #6405) (#6464) (Toru Nagashima)
• 3e690fb Fix: Exit init early if guide is chosen w/ no package.json (fixes #6476) (#6478) (Kai Cataldo)

Documentation

• 66de9d8 Docs: Update installation instructions on README (#6569) (Nicholas C. Zakas)
• 4c05967 Docs: Update rule docs for new format (fixes #5417) (#6551) (Nicholas C. Zakas)
• 70da5a8 Docs: Correct link to rules page (#fixes 6553) (#6561) (alberto)
• 666da7c Docs: 3.0.0 migration guide (#6521) (Nicholas C. Zakas)
• b9bf8fb Docs: Update Governance Policy (fixes #6452) (#6522) (Nicholas C. Zakas)
• 5f8f3e8 Docs: Remove Box as a sponsor (#6529) (Nicholas C. Zakas)
• 7dfe0ad Docs: fix max-lines samples (fixes #6516) (#6515) (Dmitriy Shekhovtsov)
• e96177b Docs: Add “Proposing a Rule Change” link to CONTRIBUTING.md (#6511) (Kevin Partington)
• bea9096 Docs: Update pull request steps (fixes #6474) (#6510) (Nicholas C. Zakas)
• 7bcf6e0 Docs: Consistent example headings & text pt3 (refs #5446) (#6492) (Guy Fraser)
• 1a328d9 Docs: Consistent example headings & text pt4 (refs #5446) (#6493) (Guy Fraser)
• ff5765e Docs: Consistent example headings & text pt2 (refs #5446)(#6491) (Guy Fraser)
• 01384fa Docs: Fixing typos (refs #5446)(#6494) (Guy Fraser)
• b7d8c7d Docs: more accurate yoda-speak (#6497) (Tony Lukasavage)
• c2c6cec Docs: Mark object-shorthand as fixable. (#6485) (Nick Heiner)
• 4545123 Docs: Rephrase documentation for no-duplicate-imports (#6463) (Simen Bekkhus)
• 1b133e3 Docs: improve no-native-reassign and specifying globals (fixes #5358) (#6462) (Toru Nagashima)

Chores

• c60341f Chore: Update index and meta for "eslint:recommended" (refs #6403) (#6539) (Mark Pedrotti)
• b179373 Chore: Remove dead code in excuteOnFiles (fixes #6467) (#6466) (Andrew Hutchings)
• 18fbc4b Chore: Simplify eslint process exit code (fixes #6368) (#6371) (alberto)