Breaking

• Require Node.js 8 8a213ef
• Upgrade to ESLint 6 698b043
• Enforce using the .json extension for JSON files in imports 7e56730

New rules

• Add prefer-named-capture-group rule (for Node.js >=10 target) 21e7b57
• Add default-param-last rule
• Add prefer-regex-literals rule
• Add no-import-assign rule
• Add unicorn/expiring-todo-comments rule
• Add unicorn/no-nested-ternary rule
• Add unicorn/prefer-reflect-apply rule
• Add unicorn/prefer-string-slice rule
• Add unicorn/prefer-dataset rule
• Add unicorn/no-for-loop rule
• Add unicorn/no-zero-fractions rule
• Add unicorn/prefer-includes rule
• Add unicorn/prefer-text-content rule
• Add unicorn/prefer-node-remove rule
• Add unicorn/prefer-event-key rule
• Add unicorn/prefer-flat-map rule
• Add node/prefer-promises/fs rule a3d74a6
• Add node/prefer-promises/dns rule 8f8fc94

Enhancements

• Respect .eslintignore (#377) f6bf4c0
• Turn all paths cwd-relative before linting (#372) 3033fcd
• Add option to import/no-useless-path-segments rule 8d6c5c5
• Add tap-snapshots/*.js to default ignore list (#385) b73b11b
• Make --stdin --fix always return the code even if nothing was fixed (#383) ec51d18

Highlights

• You can now click/Command-click the rule IDs in the output to open the rule's docs. Preview. (Only in supported terminals) sindresorhus/eslint-formatter-pretty@7606f98
• Move default ESLint cache to node_modules/.cache/xo. (#351) d1fd3e1
• Support parsing ES2019 61f9582
• Drop support for Babel 6 in the import/no-unassigned-import rule dd2c015

New rules

• padding-line-between-statements
• no-useless-catch
• unicorn/prefer-query-selector
• unicorn/prefer-node-append
• unicorn/no-unreadable-array-destructuring
• unicorn/no-console-spaces
• eslint-comments/disable-enable-pair
• eslint-comments/no-aggregating-enable
• eslint-comments/no-duplicate-disable
• eslint-comments/no-unused-disable
• eslint-comments/no-unused-enable
• node/prefer-global/buffer
• node/prefer-global/console
• node/prefer-global/process
• node/prefer-global/text-decoder (When targeting Node.js 11)
• node/prefer-global/text-encoder (When targeting Node.js 11)
• node/prefer-global/url-search-params (When targeting Node.js 10)
• node/prefer-global/url (When targeting Node.js 10)

All changes

v0.23.0...v0.24.0

Highlights

• In v0.22.0, we added support for .ts and .tsx extensions by default. This caused a lot of problems for non-TS projects, so it has been reverted pending a better solution.
• The quotes rule is now set to disallow using template literals when you're not using any interpolation. xojs/eslint-config-xo@ea693f3
• Removed the no-use-before-define rule. It has too many false-positives. xojs/eslint-config-xo@1257597

New rules

• require-await
• unicorn/prefer-exponentiation-operator
• unicorn/catch-error-name (See this thread if you're wondering why error is preferred over err) (Sorry about the churn, but this is an important milestone towards more readable code. Code is written once but read many times. We should optimize for the latter.)

All changes

v0.22.0...v0.23.0

Highlights

• Upgraded to ESLint 5.
• Removed some patterns from the list of default ignores. They were too opinionated. 00d6b7c 8e4f435
  • fixture{-*,}.{js,jsx}
  • fixture{s,}/**
  • {test,tests,spec,__tests__}/fixture{s,}/**
  • **/bundle.js
• Added support for TypeScript and documented usage with Flow. 957b0d9
• Now respects nodeVersion option set in an override block. 98dee9a
• Fixed the CLI's --space option parsing. f76c901

New rules

• no-misleading-character-class
• require-atomic-updates
• no-async-promise-executor
• ava/no-import-test-file

All changes

v0.21.1...v0.22.0

Fix space/useTabs conflict message with Prettier. 36f7f38

Highlights

• Dropped support for Node.js 4 and 5 as they reached end of life. Node.js 6 is the minimum required version.
• Upgrade to Prettier 1.12.1.
• The default value for trailingComma Prettier option is now none. f67ff58
• Disable unicorn/number-literal-case when using Prettier to avoid conflict. 4fd6991
• Ignore prettier-ignore comments in capitalized-comments rule. xojs/eslint-config-xo@6e417ff
• Fix missed detection of incorrect indentation with indent rule. xojs/eslint-config-xo@145993e
• Allow named function in prefer-arrow-callback. xojs/eslint-config-xo@bda02cb

New rules

• valid-jsdoc
• promise/no-new-statics
• promise/valid-params
• import/no-self-import
• import/no-useless-path-segments

Removed rules

• import/prefer-default-export

This release is way overdue, so glad to finally have it out! It includes a major ESLint upgrade, huge performance improvements, Prettier support, lots of new rules, and bug fixes.

The project was recently moved to a GitHub organization, and we got a new team member, Pierre Vanduynslager ✨

We now also have configs for TypeScript (using tslint) and CSS & Sass (using stylelint). And don't forget, we already have a config for React.

Many of the new rules in this release are from the eslint-plugin-unicorn plugin, which could use some contributions.

Highlights

• Upgraded to ESLint 4. a11e288
• Added optional Prettier support. fd89175
• Improved performance. 552cbb1
• Now toggles rules based on the engines field in package.json. 0d18368
• Disabled linebreak-style rule on Windows. xojs/eslint-config-xo@3f81796
• Made the spaced-comment rule more lenient. xojs/eslint-config-xo@e4f1f36
• Now allows _ as argument name in the no-unused-vars rule. xojs/eslint-config-xo@dda366b
• The --open flag now opens errors first and not warnings. 6f6a606
• Removed deprecated --compact CLI flag. 652a6e5
• Excluded babel-register and babel-polyfill from the no-unassigned-import rule. 70d6ab4
• Sets ecmaVersion to 2018. 9859dfb

New rules

22 new rules!

• semi-style xojs/eslint-config-xo@0b1680e
• for-direction xojs/eslint-config-xo@c957c7f
• switch-colon-spacing xojs/eslint-config-xo@c1c8fc7
• no-buffer-constructor xojs/eslint-config-xo@ee366cb
• getter-return xojs/eslint-config-xo@40e1442
• function-paren-newline xojs/eslint-config-xo@9e90fdc
• lines-between-class-members xojs/eslint-config-xo@c7f63cd
• array-bracket-newline xojs/eslint-config-xo@e2f3748
• unicorn/prefer-add-event-listener
• unicorn/prefer-spread rule
• unicorn/no-unsafe-regex
• unicorn/error-message
• unicorn/import-index
• unicorn/new-for-builtins
• unicorn/regex-shorthand
• unicorn/escape-case
• unicorn/no-hex-escape
• promise/no-return-wrap 4273f8a
• promise/no-return-in-finally 4273f8a
• node/no-unpublished-bin 16fb8e2
• node/process-exit-as-throw 16fb8e2
• node/no-deprecated-api 16fb8e2

All changes

v0.18.2...v0.20.0

Why is this not 0.19.0? That version got tainted by an incorrect publish a long time ago.

We finally fixed all the gitignore issues. Thanks to hard work by @marionebl and @schnittstabil.

The --open flag now also supports VS Code.

v0.18.1...v0.18.2

Removes the promise/no-promise-in-callback and promise/no-callback-in-promise rules. They were more annoying than useful. You usually have to deal with a lot of non-Promise APIs, so I had to disable it too many times. Some APIs will also never be Promise, like events and streams. 2253852

v0.18.0...v0.18.1

Highlights

• The esnext option is now true by default. This means it now enforces the use of as much ES2015+ syntax as Node.js 4 supports. 61c046c
• 21 new rules:
  • Unicorn plugin: sindresorhus/eslint-plugin-unicorn@v1.0.0...v2.1.0
    • no-array-instanceof
    • no-new-buffer
    • no-hex-escape
    • number-literal-case
    • escape-case
    • prefer-starts-ends-with
    • custom-error-definition
    • type-error
  • AVA plugin: avajs/eslint-plugin-ava@a0156f1
    • no-async-fn-without-await
    • no-duplicate-modifiers
  • Promise plugin: 3e1a318
    • no-promise-in-callback
    • no-callback-in-promise
  • ESLint: xojs/eslint-config-xo@v0.17.0...v0.18.0
    • func-name-matching
    • no-compare-neg-zero
    • template-tag-spacing
    • no-multi-assign
    • prefer-promise-reject-errors
    • no-await-in-loop
    • capitalized-comments
    • no-return-await
    • no-useless-return
• 27 additional ESLint rules are now auto-fixable with $ xo --fix.
• Handle negative gitignore patterns correctly. f8e1e3d
• Vim plugin for XO.
• Added --stdin-filename CLI flag. 0d88cde
• Added support for auto-fixing code from stdin. 6d6d642
• Added tip on how to use XO with monorepos. cb63c5f
• Removed the import/no-dynamic-require rule. 29a5263
• Ignores directories when receiving an empty extension. a0ae248
• Don't trigger import duplication errors for Flow type imports. da188e5

All changes

v0.17.1...v0.18.0