ESLint v4.0.0-beta.0 released

We just pushed ESLint v4.0.0-beta.0, which is a major release upgrade of ESLint. This release adds some new features and fixes several bugs found in the previous release. This release also has some breaking changes, so please read the following closely.

Note: This version of ESLint is not ready for production use and is provided to gather feedback from the community before releasing the final version. Please let us know if you having any problems or feedback by creating issues on our GitHub repo or joining our Gitter channel.

Highlights

• If you're upgrading from 3.x, see the migration guide.
• Four new rules have been added in this release:
  • semi-style
  • padding-line-between-statements
  • for-direction
  • switch-colon-spacing
• Previously, ESLint's Node.js API exposed a mutable eslint.linter object which could be used to lint text. This could cause problems if two unrelated modules were using eslint.linter at the same time, because they might both mutate it and interfere with each other. To resolve this, ESLint now exposes an eslint.Linter constructor, which can be used to create mutable linter instances. We recommend that integrations switch to using eslint.Linter rather than eslint.linter.
• Three rules have been deprecated in favor of the new padding-line-between-statements rule:
  • lines-around-directive
  • newline-after-var
  • newline-before-return

Breaking Changes

• 3ec436ee Breaking: New Linter API (fixes #8454) (#8465) (Gyandeep Singh)

Features

• 2f7015b6 New: semi-style rule (fixes #8169) (#8542) (Toru Nagashima)
• a93a2f95 New: padding-line-between-statements rule (fixes #7356) (#8099) (Toru Nagashima)
• 0ef09ea0 New: for-direction rule (fixes #8387) (#8519) (薛定谔的猫)
• 482d5720 New: switch-colon-spacing rule (fixes #7981) (#8540) (Toru Nagashima)

Enhancements

• 3418479a Update: improve indent of flatTernaryExpressions (fixes #8481) (#8587) (Toru Nagashima)
• 268d52ef Update: Use sane defaults for JSX indentation (fixes #8425) (#8593) (Teddy Katz)
• afa35c68 Update: check allman-style classes correctly in indent (fixes #8493) (#8569) (Teddy Katz)
• 456f519b Update: make indent MemberExpression handling more robust (fixes #8552) (#8554) (Teddy Katz)

Bug Fixes

• eb14584a Fix: no-unneeded-ternary change code behavior after fix (fixes #8507) (#8624) (Jan Peer Stöcklmair)
• 3fc9653a Fix: Call expression consistency in variable declaration (fixes #8607) (#8619) (Reyad Attiyat)
• a73e6c09 Fix: Fix failing uknown node test since #8569 indents class bodies (#8588) (Reyad Attiyat)
• c6c639d6 Fix: Ignore unknown nodes for Indent rule (fixes #8440) (#8504) (Reyad Attiyat)
• df17bc87 Fix: object-shorthand crash on some computed keys (fixes #8576) (#8577) (Teddy Katz)
• de0b4ad7 Fix: Indent Ignore Variable Declaration init operator (fixes #8546) (#8563) (Reyad Attiyat)
• 927ca0dc Fix: invalid syntax from prefer-arrow-callback autofixer (fixes #8541) (#8555) (Teddy Katz)
• 873310e5 Fix: run no-unexpected-multiline only if needed (fixes #8550) (#8551) (Ruben Bridgewater)
• 833a0cad Fix: confusing RuleTester error message when options is not an array (#8557) (Teddy Katz)

Documentation

• 5b6093ef Docs: Remove .eslintignore reference to transpiled file filtering (#8622) (Alex Summer)
• 11493781 Docs: Rephrase in about section (#8609) (Sudarsan G P)

Chores

• 729bbcdb Chore: Fix lgtm alerts. (#8611) (Max Schaefer)
• d21f5283 Chore: make shelljs a devDependency instead of a dependency (#8608) (Teddy Katz)
• 23401626 Chore: remove strip-bom dependency (refs #8603) (#8606) (Teddy Katz)
• 25db3d22 Chore: avoid skipping test for env overrides (refs #8291) (#8556) (Teddy Katz)