ESLint v5.0.0-alpha.4 released

We just pushed ESLint v5.0.0-alpha.4, which is a major release upgrade of ESLint. This release adds some new features and fixes several bugs found in the previous release.

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

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@5.0.0-alpha.4 --save-dev

Migration Guide

As there are a lot of changes, we've created a migration guide describing the 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

• 465e615 New: prompt users before installing dependencies (#10353) (Pig Fang)

Enhancements

• 93c9a52 Update: config-validator should validate overrides (#10357) (Toru Nagashima)
• c2e0398 Update: Improves the prefer-object-spread rule by removing extraneous visitors (#10351) (Sharmila Jesupaul)
• d848949 Update: Support JSXFragment node (fixes #9662) (#9664) (Clement Hoang)
• 9c922ce Update: Add "consistent" option to array-element-newline (fixes #9457) (#10355) (Pig Fang)

Bug Fixes

• 240c1a4 Fix: prefer-const object destructuring false positive (fixes #9108) (#10368) (Pig Fang)
• 65bce3a Fix: ensure --stdin flag works when stdin is piped asynchronously (#10393) (Teddy Katz)
• 8b7a70c Fix: handle one-var with no semicolon (fixes #10330) (#10371) (Malcolm Groves)
• fb148aa Fix: allow no tokens after return keyword (fixes #10372) (#10379) (Pig Fang)
• a812845 Fix: allow array spread for prefer-object-spread rule (fixes #10344) (#10347) (Pig Fang)

Documentation

• ce3e62a Docs: remove test coverage badge (#10407) (薛定谔的猫)
• 074bc1c Docs: polish for max-classes-per-file rule (#10377) (Pig Fang)
• 448fc52 Docs: Update link to Integrations / Build tools / Start (#10354) (Kir Belevich)

Build Related

• f268128 Build: add Node v10 to travis (#10262) (alberto)

Chores

• b9b23a9 Chore: rm unused argument (#10400) (薛定谔的猫)
• e25fc22 Chore: remove assert.doesNotThrow in tests (#10199) (Ruben Bridgewater)
• 4e5e9be Chore: avoid unnecessary filesystem accesses during config search (#10359) (Teddy Katz)
• 363da01 Chore: avoid code duplication in rule severity checking (#10358) (Teddy Katz)