ESLint v2.3.0 released

We just pushed ESLint v2.3.0, which is a minor release upgrade of ESLint. This release adds some new features and fixes several bugs found in the previous release.


Here are some highlights of changes in this release.

Support for string severity in configs

v2.3.0 introduces ability to use strings as severity level in configuration files. Before you had to use number 0, 1 and 2 to configure rules. Now we also added ability to use strings. You can now use:

  • off - 0
  • warn - 1
  • error - 2

Both string and int values will work the same way

EcmaScript version 7 Support

We recently updated our parser Espree with support for new exponentiation operator. You can now set ecmaVersion to 7 under parserOptions. We also updated space-infix-ops to support new ** operator.

Improved error messaging for plugins

If ESLint fails to find a plugin required by the config file, we will now print a clear message explaining to user what needs to be done to fix this issue.


  • 9e9daab New: newline-before-return rule (fixes #5009) (Kai Cataldo)
  • 560c0d9 New: no-restricted-globals rule implementation (fixes #3966) (Benoît Zugmeyer)


  • 1b2c6e0 Update: Proposed no-magic-numbers option: ignoreJSXNumbers (fixes #5348) (Brandon Beeks)
  • 0547072 Update: Replace getLast() with lodash.last() (fixes #5456) (Jordan Eldredge)
  • 4a67b9a Update: Add ES7 support (fixes #5401) (Brandon Mills)
  • 4f82b2b Update: Support classes in padded-blocks (fixes #5092) (alberto)
  • 70e3a02 Update: Allow string severity in config (fixes #3626) (Nicholas C. Zakas)
  • 13c7c19 Update: Exclude ES5 constructors from consistent-return (fixes #5379) (Kevin Locke)
  • 6280b2d Update: Support switch statements in padded-blocks (fixes #5056) (alberto)
  • 8f6c2e7 Update: Better error message for plugins (refs #5221) (Nicholas C. Zakas)
  • 972d41b Update: Improve error message for rule-tester (fixes #5369) (Jeroen Engels)
  • 1f9fd10 Update: no-invalid-regexp allows custom flags (fixes #5249) (Afnan Fahim)
  • 6aa2380 Update: prefer-const; change modified to reassigned (fixes #5350) (Michiel de Bruijne)

Bug Fixes

  • 50f4d5a Fix: extends chain (fixes #5411) (Toru Nagashima)
  • 1da2420 Fix: crash when SourceCode object was reused (fixes #5007) (Toru Nagashima)
  • e1bbe45 Fix: Check space after anonymous generator star (fixes #5435) (alberto)
  • 905c049 Fix: no-undef false positive at (fixes #5420) (Toru Nagashima)
  • de0a4ef Fix: getFormatter throws an error when called as static (fixes #5378) (cowchimp)
  • 78f7ca9 Fix: Prevent crash from swallowing console.log (fixes #5381) (Ian VanSchooten)
  • 34b648d Fix: remove tests which have invalid syntax (fixes #5405) (Toru Nagashima)
  • cf14c71 Fix: no-useless-constructor rule crashes sometimes (fixes #5290) (Burak Yigit Kaya)
  • 784d3bf Fix: Location info in dot-notation rule (fixes #5397) (Gyandeep Singh)
  • 25a5b2c Fix: Allow irregular whitespace in comments (fixes #5368) (Christophe Porteneuve)
  • c5bb478 Fix: constructor-super false positive after a loop (fixes #5394) (Toru Nagashima)
  • 1170e67 Fix: indent rule doesn’t handle constructor instantiation (fixes #5384) (Nate Cavanaugh)
  • 6bc9932 Fix: Avoid magic numbers in rule options (fixes #4182) (Brandon Beeks)
  • 694e1c1 Fix: Add tests to cover default magic number tests (fixes #5385) (Brandon Beeks)
  • 0b5349d Fix: .eslintignore paths should be absolute (fixes #5362) (alberto)
  • fe3f6bd Fix: no-self-assign false positive at shorthand (fixes #5371) (Toru Nagashima)
  • f1eab9b Fix: Support for dash and slash in valid-jsdoc (fixes #1598) (Gyandeep Singh)
  • cd12a4b Fix:newline-per-chained-call should only warn on methods (fixes #5289) (Burak Yigit Kaya)
  • d1d62c6 Fix: indent check for else keyword with Stroustrup style (fixes #5218) (Gyandeep Singh)
  • 1c347f5 Fix: Cleanup temp files from tests (fixes #5338) (Nick)


  • 63c0b7d Docs: Fix incorrect environment ref. in Rules in Plugins. (fixes #5421) (Jesse McCarthy)
  • 0d3831b Docs: Add RuleTester parserOptions migration steps (Kevin Partington)
  • 8c29946 Docs: Distinguish examples in rules under Possible Errors part 1 (Mark Pedrotti)
  • 5319b4a Docs: Distinguish examples in rules under Possible Errors part 2 (Mark Pedrotti)
  • 119e0ed Docs: Distinguish examples in rules under Variables (Mark Pedrotti)
  • 89c757d Docs: Replace ecmaFeatures with parserOptions in working-with-rules (Kevin Partington)
  • 804c08e Docs: Add parserOptions to RuleTester section of working-with-rules (Kevin Partington)
  • 1982c50 Docs: Document string option for no-unused-vars. (alberto)
  • ed5564f Docs: Specify results of no-unused-var with args (fixes #5334) (chinesedfan)
  • 7de5ae4 Docs: Missing allow option in docs (Scott O’Hara)
  • 6c0c4aa Docs: Add Issue template (fixes #5313) (Kai Cataldo)
  • 2376291 Docs: Missing space in no-fallthrough doc. (alberto)
  • 5aedb87 Docs: Add mysticatea as reviewer (Nicholas C. Zakas)
  • 0d1377d Docs: Add missing symbol type into valid list (Plusb Preco)
  • 36f40c2 Docs: Achieve consistent order of h2 in rule pages (Mark Pedrotti)
  • 124c447 Build: Add additional linebreak to docs (fixes #5464) (Ilya Volodin)
  • 7932f78 Build: Fix commit message validation (fixes #5340) (Nicholas C. Zakas)
  • 2f3e1ae Build: Change rules to warnings in perf test (fixes #5330) (Brandon Mills)

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