[eslint config] v18.2.0

Co-authored-by: Kristóf Poduszló <kripod@protonmail.com>
Co-authored-by: Jordan Harband <ljharb@gmail.com>

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+end_of_line = lf
+# editorconfig-tools is unable to ignore longs strings or urls
+max_line_length = off
+
+[CHANGELOG.md]
+indent_size = false

.gitignore

@@ -1 +1,7 @@
+# gitignore
+
 node_modules
+
+# Only apps should have lockfiles
+yarn.lock
+package-lock.json

.npmrc

@@ -0,0 +1 @@
+package-lock=false

.travis.yml

@@ -1,17 +1,108 @@
 language: node_js
 node_js:
-  - "6"
-  - "5"
-  - "4"
-env:
-  - 'TEST_DIR=packages/eslint-config-airbnb'
-  - 'TEST_DIR=packages/eslint-config-airbnb-base'
+  - "14"
+  - "12"
+  - "10"
 before_install:
-  - 'cd $TEST_DIR'
-  - 'if [ "${TRAVIS_NODE_VERSION}" != "0.9" ]; then case "$(npm --version)" in 1.*) npm install -g npm@1.4.28 ;; 2.*) npm install -g npm@2 ;; esac ; fi'
-  - 'if [ "${TRAVIS_NODE_VERSION}" != "0.6" ] && [ "${TRAVIS_NODE_VERSION}" != "0.9" ]; then npm install -g npm; fi'
+  - 'nvm install-latest-npm'
+install:
+  - 'if [ -n "${PACKAGE-}" ]; then cd "packages/${PACKAGE}"; fi'
+  - 'if [ "${TRAVIS_NODE_VERSION}" = "0.6" ] || [ "${TRAVIS_NODE_VERSION}" = "0.9" ]; then nvm install --latest-npm 0.8 && npm install && nvm use "${TRAVIS_NODE_VERSION}"; else npm install; fi;'
+  - 'if [ -n "${ESLINT}" ]; then npm install --no-save "eslint@${ESLINT}"; fi'
+  - 'if [ -n "${REACT_HOOKS}" ]; then npm install --no-save "eslint-plugin-react-hooks@${REACT_HOOKS}"; fi'
 script:
-  - 'npm run travis'
+  - 'if [ -n "${PREPUBLISH-}" ]; then npm run pretravis && npm run prepublish && npm run posttravis; elif [ -n "${LINT-}" ]; then npm run lint; else npm run travis; fi'
 sudo: false
+env:
+  matrix:
+    - 'TEST=true ESLINT=7 PACKAGE=eslint-config-airbnb-base'
+    - 'TEST=true ESLINT=7 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=7 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=7 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=7 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=6 PACKAGE=eslint-config-airbnb-base'
+    - 'TEST=true ESLINT=6 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=6 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=6 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=6 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=5 PACKAGE=eslint-config-airbnb-base'
+    - 'TEST=true ESLINT=5 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=5 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=5 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb'
+    - 'TEST=true ESLINT=5 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb'
 matrix:
   fast_finish: true
+  include:
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=7 PACKAGE=eslint-config-airbnb-base
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=7 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=7 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=7 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=7 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=6 PACKAGE=eslint-config-airbnb-base
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=6 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=6 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=6 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=6 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=5 PACKAGE=eslint-config-airbnb-base
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=5 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=5 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=5 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: PREPUBLISH=true ESLINT=5 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: LINT=true
+    - node_js: "lts/*"
+      env: LINT=true PACKAGE=eslint-config-airbnb
+    - node_js: "lts/*"
+      env: LINT=true PACKAGE=eslint-config-airbnb-base
+    - node_js: "8"
+      env: TEST=true ESLINT=6 PACKAGE=eslint-config-airbnb-base
+    - node_js: "8"
+      env: TEST=true ESLINT=6 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=6 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=6 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=6 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=5 PACKAGE=eslint-config-airbnb-base
+    - node_js: "8"
+      env: TEST=true ESLINT=5 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=5 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=5 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb
+    - node_js: "8"
+      env: TEST=true ESLINT=5 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb
+    - node_js: "6"
+      env: TEST=true ESLINT=5 PACKAGE=eslint-config-airbnb-base
+    - node_js: "6"
+      env: TEST=true ESLINT=5 PACKAGE=eslint-config-airbnb
+    - node_js: "6"
+      env: TEST=true ESLINT=5 REACT_HOOKS=3 PACKAGE=eslint-config-airbnb
+    - node_js: "6"
+      env: TEST=true ESLINT=5 REACT_HOOKS=2.3 PACKAGE=eslint-config-airbnb
+    - node_js: "6"
+      env: TEST=true ESLINT=5 REACT_HOOKS=1.7 PACKAGE=eslint-config-airbnb
+  exclude:
+  allow_failures:
+    - env: PREPUBLISH=true ESLINT=6 PACKAGE=eslint-config-airbnb-base
+    - env: PREPUBLISH=true ESLINT=6 PACKAGE=eslint-config-airbnb
+    - env: PREPUBLISH=true ESLINT=5 PACKAGE=eslint-config-airbnb-base
+    - env: PREPUBLISH=true ESLINT=5 PACKAGE=eslint-config-airbnb

LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2012 Airbnb
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

css-in-javascript/README.md

@@ -0,0 +1,432 @@
+# Airbnb CSS-in-JavaScript Style Guide
+
+*A mostly reasonable approach to CSS-in-JavaScript*
+
+## Table of Contents
+
+1. [Naming](#naming)
+1. [Ordering](#ordering)
+1. [Nesting](#nesting)
+1. [Inline](#inline)
+1. [Themes](#themes)
+
+## Naming
+
+  - Use camelCase for object keys (i.e. "selectors").
+
+    > Why? We access these keys as properties on the `styles` object in the component, so it is most convenient to use camelCase.
+
+    ```js
+    // bad
+    {
+      'bermuda-triangle': {
+        display: 'none',
+      },
+    }
+
+    // good
+    {
+      bermudaTriangle: {
+        display: 'none',
+      },
+    }
+    ```
+
+  - Use an underscore for modifiers to other styles.
+
+    > Why? Similar to BEM, this naming convention makes it clear that the styles are intended to modify the element preceded by the underscore. Underscores do not need to be quoted, so they are preferred over other characters, such as dashes.
+
+    ```js
+    // bad
+    {
+      bruceBanner: {
+        color: 'pink',
+        transition: 'color 10s',
+      },
+
+      bruceBannerTheHulk: {
+        color: 'green',
+      },
+    }
+
+    // good
+    {
+      bruceBanner: {
+        color: 'pink',
+        transition: 'color 10s',
+      },
+
+      bruceBanner_theHulk: {
+        color: 'green',
+      },
+    }
+    ```
+
+  - Use `selectorName_fallback` for sets of fallback styles.
+
+    > Why? Similar to modifiers, keeping the naming consistent helps reveal the relationship of these styles to the styles that override them in more adequate browsers.
+
+    ```js
+    // bad
+    {
+      muscles: {
+        display: 'flex',
+      },
+
+      muscles_sadBears: {
+        width: '100%',
+      },
+    }
+
+    // good
+    {
+      muscles: {
+        display: 'flex',
+      },
+
+      muscles_fallback: {
+        width: '100%',
+      },
+    }
+    ```
+
+  - Use a separate selector for sets of fallback styles.
+
+    > Why? Keeping fallback styles contained in a separate object clarifies their purpose, which improves readability.
+
+    ```js
+    // bad
+    {
+      muscles: {
+        display: 'flex',
+      },
+
+      left: {
+        flexGrow: 1,
+        display: 'inline-block',
+      },
+
+      right: {
+        display: 'inline-block',
+      },
+    }
+
+    // good
+    {
+      muscles: {
+        display: 'flex',
+      },
+
+      left: {
+        flexGrow: 1,
+      },
+
+      left_fallback: {
+        display: 'inline-block',
+      },
+
+      right_fallback: {
+        display: 'inline-block',
+      },
+    }
+    ```
+
+  - Use device-agnostic names (e.g. "small", "medium", and "large") to name media query breakpoints.
+
+    > Why? Commonly used names like "phone", "tablet", and "desktop" do not match the characteristics of the devices in the real world. Using these names sets the wrong expectations.
+
+    ```js
+    // bad
+    const breakpoints = {
+      mobile: '@media (max-width: 639px)',
+      tablet: '@media (max-width: 1047px)',
+      desktop: '@media (min-width: 1048px)',
+    };
+
+    // good
+    const breakpoints = {
+      small: '@media (max-width: 639px)',
+      medium: '@media (max-width: 1047px)',
+      large: '@media (min-width: 1048px)',
+    };
+    ```
+
+## Ordering
+
+  - Define styles after the component.
+
+    > Why? We use a higher-order component to theme our styles, which is naturally used after the component definition. Passing the styles object directly to this function reduces indirection.
+
+    ```jsx
+    // bad
+    const styles = {
+      container: {
+        display: 'inline-block',
+      },
+    };
+
+    function MyComponent({ styles }) {
+      return (
+        <div {...css(styles.container)}>
+          Never doubt that a small group of thoughtful, committed citizens can
+          change the world. Indeed, it’s the only thing that ever has.
+        </div>
+      );
+    }
+
+    export default withStyles(() => styles)(MyComponent);
+
+    // good
+    function MyComponent({ styles }) {
+      return (
+        <div {...css(styles.container)}>
+          Never doubt that a small group of thoughtful, committed citizens can
+          change the world. Indeed, it’s the only thing that ever has.
+        </div>
+      );
+    }
+
+    export default withStyles(() => ({
+      container: {
+        display: 'inline-block',
+      },
+    }))(MyComponent);
+    ```
+
+## Nesting
+
+  - Leave a blank line between adjacent blocks at the same indentation level.
+
+    > Why? The whitespace improves readability and reduces the likelihood of merge conflicts.
+
+    ```js
+    // bad
+    {
+      bigBang: {
+        display: 'inline-block',
+        '::before': {
+          content: "''",
+        },
+      },
+      universe: {
+        border: 'none',
+      },
+    }
+
+    // good
+    {
+      bigBang: {
+        display: 'inline-block',
+
+        '::before': {
+          content: "''",
+        },
+      },
+
+      universe: {
+        border: 'none',
+      },
+    }
+    ```
+
+## Inline
+
+  - Use inline styles for styles that have a high cardinality (e.g. uses the value of a prop) and not for styles that have a low cardinality.
+
+    > Why? Generating themed stylesheets can be expensive, so they are best for discrete sets of styles.
+
+    ```jsx
+    // bad
+    export default function MyComponent({ spacing }) {
+      return (
+        <div style={{ display: 'table', margin: spacing }} />
+      );
+    }
+
+    // good
+    function MyComponent({ styles, spacing }) {
+      return (
+        <div {...css(styles.periodic, { margin: spacing })} />
+      );
+    }
+    export default withStyles(() => ({
+      periodic: {
+        display: 'table',
+      },
+    }))(MyComponent);
+    ```
+
+## Themes
+
+  - Use an abstraction layer such as [react-with-styles](https://github.com/airbnb/react-with-styles) that enables theming. *react-with-styles gives us things like `withStyles()`, `ThemedStyleSheet`, and `css()` which are used in some of the examples in this document.*
+
+  > Why? It is useful to have a set of shared variables for styling your components. Using an abstraction layer makes this more convenient. Additionally, this can help prevent your components from being tightly coupled to any particular underlying implementation, which gives you more freedom.
+
+  - Define colors only in themes.
+
+    ```js
+    // bad
+    export default withStyles(() => ({
+      chuckNorris: {
+        color: '#bada55',
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ color }) => ({
+      chuckNorris: {
+        color: color.badass,
+      },
+    }))(MyComponent);
+    ```
+
+  - Define fonts only in themes.
+
+    ```js
+    // bad
+    export default withStyles(() => ({
+      towerOfPisa: {
+        fontStyle: 'italic',
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ font }) => ({
+      towerOfPisa: {
+        fontStyle: font.italic,
+      },
+    }))(MyComponent);
+    ```
+
+  - Define fonts as sets of related styles.
+
+    ```js
+    // bad
+    export default withStyles(() => ({
+      towerOfPisa: {
+        fontFamily: 'Italiana, "Times New Roman", serif',
+        fontSize: '2em',
+        fontStyle: 'italic',
+        lineHeight: 1.5,
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ font }) => ({
+      towerOfPisa: {
+        ...font.italian,
+      },
+    }))(MyComponent);
+    ```
+
+  - Define base grid units in theme (either as a value or a function that takes a multiplier).
+
+    ```js
+    // bad
+    export default withStyles(() => ({
+      rip: {
+        bottom: '-6912px', // 6 feet
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ units }) => ({
+      rip: {
+        bottom: units(864), // 6 feet, assuming our unit is 8px
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ unit }) => ({
+      rip: {
+        bottom: 864 * unit, // 6 feet, assuming our unit is 8px
+      },
+    }))(MyComponent);
+    ```
+
+  - Define media queries only in themes.
+
+    ```js
+    // bad
+    export default withStyles(() => ({
+      container: {
+        width: '100%',
+
+        '@media (max-width: 1047px)': {
+          width: '50%',
+        },
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ breakpoint }) => ({
+      container: {
+        width: '100%',
+
+        [breakpoint.medium]: {
+          width: '50%',
+        },
+      },
+    }))(MyComponent);
+    ```
+
+  - Define tricky fallback properties in themes.
+
+    > Why? Many CSS-in-JavaScript implementations merge style objects together which makes specifying fallbacks for the same property (e.g. `display`) a little tricky. To keep the approach unified, put these fallbacks in the theme.
+
+    ```js
+    // bad
+    export default withStyles(() => ({
+      .muscles {
+        display: 'flex',
+      },
+
+      .muscles_fallback {
+        'display ': 'table',
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ fallbacks }) => ({
+      .muscles {
+        display: 'flex',
+      },
+
+      .muscles_fallback {
+        [fallbacks.display]: 'table',
+      },
+    }))(MyComponent);
+
+    // good
+    export default withStyles(({ fallback }) => ({
+      .muscles {
+        display: 'flex',
+      },
+
+      .muscles_fallback {
+        [fallback('display')]: 'table',
+      },
+    }))(MyComponent);
+    ```
+
+  - Create as few custom themes as possible. Many applications may only have one theme.
+
+  - Namespace custom theme settings under a nested object with a unique and descriptive key.
+
+    ```js
+    // bad
+    ThemedStyleSheet.registerTheme('mySection', {
+      mySectionPrimaryColor: 'green',
+    });
+
+    // good
+    ThemedStyleSheet.registerTheme('mySection', {
+      mySection: {
+        primaryColor: 'green',
+      },
+    });
+    ```
+
+---
+
+CSS puns adapted from [Saijo George](https://saijogeorge.com/css-puns/).

linters/.markdownlint.json

@@ -0,0 +1,155 @@
+{
+  "comment": "Be explicit by listing every available rule. https://github.com/DavidAnson/markdownlint/blob/master/doc/Rules.md",
+  "comment": "Note that there will be numeric gaps, not every MD number is implemented in markdownlint.",
+
+  "comment": "MD001: Header levels should only increment by one level at a time.",
+  "header-increment": true,
+
+  "comment": "MD002: First header should be a top level header.",
+  "first-header-h1": true,
+
+  "comment": "MD003: Header style: start with hashes.",
+  "header-style": {
+    "style": "atx"
+  },
+
+  "comment": "MD004: Unordered list style",
+  "ul-style": {
+    "style": "dash"
+  },
+
+  "comment": "MD005: Consistent indentation for list items at the same level.",
+  "list-indent": true,
+
+  "comment": "MD006: Consider starting bulleted lists at the beginning of the line.",
+  "ul-start-left": false,
+
+  "comment": "MD007: Unordered list indentation: 2 spaces.",
+  "ul-indent": {
+    "indent": 2,
+    "start_indented": true
+  },
+
+  "comment": "MD009: Disallow trailing spaces!",
+  "no-trailing-spaces": {
+    "br_spaces": 0,
+    "comment": "Empty lines inside list items should not be indented.",
+    "list_item_empty_lines": false
+  },
+
+  "comment": "MD010: No hard tabs, not even in code blocks.",
+  "no-hard-tabs": {
+    "code_blocks": true
+  },
+
+  "comment": "MD011: Prevent reversed link syntax",
+  "no-reversed-links": true,
+
+  "comment": "MD012: Disallow multiple consecutive blank lines.",
+  "no-multiple-blanks": {
+    "maximum": 1
+   },
+
+  "comment": "MD013: Line length",
+  "line-length": false,
+
+  "comment": "MD014: Disallow use of dollar signs($) before commands without showing output.",
+  "commands-show-output": true,
+
+  "comment": "MD018: Disallow space after hash on atx style header.",
+  "no-missing-space-atx": true,
+
+  "comment": "MD019: Disallow multiple spaces after hash on atx style header.",
+  "no-multiple-space-atx": true,
+
+  "comment": "MD020: No space should be inside hashes on closed atx style header.",
+  "no-missing-space-closed-atx": true,
+
+  "comment": "MD021: Disallow multiple spaces inside hashes on closed atx style header.",
+  "no-multiple-space-closed-atx": true,
+
+  "comment": "MD022: Headers should be surrounded by blank lines.",
+  "comment": "Some headers have preceeding HTML anchors. Unfortunate that we have to disable this, as it otherwise catches a real problem that trips up some Markdown renderers",
+  "blanks-around-headers": false,
+
+  "comment": "MD023: Headers must start at the beginning of the line.",
+  "header-start-left": true,
+
+  "comment": "MD024: Disallow multiple headers with the same content.",
+  "no-duplicate-header": true,
+
+  "comment": "MD025: Disallow multiple top level headers in the same document.",
+  "comment": "Gotta have a matching closing brace at the end.",
+  "single-h1": false,
+
+  "comment": "MD026: Disallow trailing punctuation in header.",
+  "comment": "You must have a semicolon after the ending closing brace.",
+  "no-trailing-punctuation": {
+    "punctuation" : ".,:!?"
+  },
+  "comment": "MD027: Dissalow multiple spaces after blockquote symbol",
+  "no-multiple-space-blockquote": true,
+
+  "comment": "MD028: Blank line inside blockquote",
+  "comment": "Some 'Why?' and 'Why not?' blocks are separated by a blank line",
+  "no-blanks-blockquote": false,
+
+  "comment": "MD029: Ordered list item prefix",
+  "ol-prefix": {
+    "style": "one"
+  },
+
+  "comment": "MD030: Spaces after list markers",
+  "list-marker-space": {
+    "ul_single": 1,
+    "ol_single": 1,
+    "ul_multi": 1,
+    "ol_multi": 1
+  },
+
+  "comment": "MD031: Fenced code blocks should be surrounded by blank lines",
+  "blanks-around-fences": true,
+
+  "comment": "MD032: Lists should be surrounded by blank lines",
+  "comment": "Some lists have preceeding HTML anchors. Unfortunate that we have to disable this, as it otherwise catches a real problem that trips up some Markdown renderers",
+  "blanks-around-lists": false,
+
+  "comment": "MD033: Disallow inline HTML",
+  "comment": "HTML is needed for explicit anchors",
+  "no-inline-html": false,
+
+  "comment": "MD034: No bare URLs should be used",
+  "no-bare-urls": true,
+
+  "comment": "MD035: Horizontal rule style",
+  "hr-style": {
+    "style": "consistent"
+  },
+
+  "comment": "MD036: Do not use emphasis instead of a header.",
+  "no-emphasis-as-header": false,
+
+  "comment": "MD037: Disallow spaces inside emphasis markers.",
+  "no-space-in-emphasis": true,
+
+  "comment": "MD038: Disallow spaces inside code span elements.",
+  "no-space-in-code": true,
+
+  "comment": "MD039: Disallow spaces inside link text.",
+  "no-space-in-links": true,
+
+  "comment": "MD040: Fenced code blocks should have a language specified.",
+  "fenced-code-language": true,
+
+  "comment": "MD041: First line in file should be a top level header.",
+  "first-line-h1": true,
+
+  "comment": "MD042: No empty links",
+  "no-empty-links": true,
+
+  "comment": "MD043: Required header structure.",
+  "required-headers": false,
+
+  "comment": "MD044: Proper names should have the correct capitalization.",
+  "proper-names": false
+}

package.json

@@ -4,11 +4,15 @@
   "description": "A mostly reasonable approach to JavaScript.",
   "scripts": {
     "preinstall": "npm run install:config && npm run install:config:base",
+    "postinstall": "rm -rf node_modules/markdownlint-cli/node_modules/markdownlint",
     "install:config": "cd packages/eslint-config-airbnb && npm prune && npm install",
     "install:config:base": "cd packages/eslint-config-airbnb-base && npm prune && npm install",
+    "lint": "markdownlint --config linters/.markdownlint.json README.md */README.md",
+    "pretest": "npm run --silent lint",
     "test": "npm run --silent test:config && npm run --silent test:config:base",
     "test:config": "cd packages/eslint-config-airbnb; npm test",
     "test:config:base": "cd packages/eslint-config-airbnb-base; npm test",
+    "pretravis": "npm run --silent lint",
     "travis": "npm run --silent travis:config && npm run --silent travis:config:base",
     "travis:config": "cd packages/eslint-config-airbnb; npm run travis",
     "travis:config:base": "cd packages/eslint-config-airbnb-base; npm run travis"
@@ -23,6 +27,9 @@
     "airbnb",
     "es6",
     "es2015",
+    "es2016",
+    "es2017",
+    "es2018",
     "react",
     "jsx"
   ],
@@ -31,5 +38,9 @@
   "bugs": {
     "url": "https://github.com/airbnb/javascript/issues"
   },
-  "homepage": "https://github.com/airbnb/javascript"
+  "homepage": "https://github.com/airbnb/javascript",
+  "devDependencies": {
+    "markdownlint": "^0.20.3",
+    "markdownlint-cli": "^0.23.1"
+  }
 }

packages/eslint-config-airbnb-base/.editorconfig

@@ -0,0 +1 @@
+../../.editorconfig

packages/eslint-config-airbnb-base/.eslintrc

@@ -3,6 +3,6 @@
   "rules": {
     // disable requiring trailing commas because it might be nice to revert to
     // being JSON at some point, and I don't want to make big changes now.
-    "comma-dangle": 0
-  }
+    "comma-dangle": 0,
+  },
 }

packages/eslint-config-airbnb-base/.npmrc

@@ -0,0 +1 @@
+../../.npmrc

packages/eslint-config-airbnb-base/CHANGELOG.md

@@ -1,3 +1,266 @@
+14.2.0 / 2020-06-10
+==================
+ - [new] add `eslint` `v7`
+ - [minor] Disallow multiple empty lines (#2238)
+ - [minor] Fix typo in no-multiple-empty-lines rule (#2168)
+ - [patch] Include 'context' exception for `no-param-reassign` (#2230)
+ - [patch] Allow triple-slash (///) comments (#2197)
+ - [patch] Disable `prefer-object-spread` for `airbnb-base/legacy` (#2198)
+ - [deps] update `eslint-plugin-import`, `eslint-plugin-react`, `babel-preset-airbnb`, `eslint-find-rules`, `in-publish`, `tape`, `object.entries`
+
+14.1.0 / 2020-03-12
+==================
+ - [minor] add new disabled rules, update eslint
+ - [minor] enable `import/no-useless-path-segments` for commonjs (#2113)
+ - [fix] `whitespace`: only set erroring rules to "warn"
+ - Fix indentation with JSX Fragments (#2157)
+ - [patch] `import/no-extraneous-dependencies`: Support karma config files (#2121)
+ - [readme] normalize multiline word according to merriam-webster (#2138)
+ - [deps] update `eslint`, `eslint-plugin-import`, `eslint-plugin-react`, `object.entries`, `confusing-browser-globals`
+ - [dev deps] update `@babel/runtime`, `babel-preset-airbnb`, `safe-publish-latest`, `tape`
+ - [tests] re-enable eslint rule `prefer-destructuring` internally (#2110)
+
+14.0.0 / 2019-08-09
+==================
+ - [breaking] `no-self-assign`: enable `props` option
+ - [breaking] enable `no-useless-catch`
+ - [breaking] enable `max-classes-per-file`
+ - [breaking] enable `no-misleading-character-class`
+ - [breaking] enable `no-async-promise-executor`
+ - [breaking] enable `prefer-object-spread`
+ - [breaking] `func-name-matching`: enable `considerPropertyDescriptor` option
+ - [breaking] `padded-blocks`: enable `allowSingleLineBlocks` option (#1255)
+ - [breaking] `no-multiple-empty-lines`: Restrict empty lines at beginning of file (#2042)
+ - [breaking] Set 'strict' to 'never' (#1962)
+ - [breaking] legacy: Enable 'strict' (#1962)
+ - [breaking] Simplifies `no-mixed-operators` (#1864)
+ - [breaking] Require parens for arrow function args (#1863)
+ - [breaking] add eslint v6, drop eslint v4
+ - [patch] `camelcase`: enable ignoreDestructuring
+ - [patch] Add markers to spaced-comment block for Flow types (#1966)
+ - [patch] Do not prefer destructuring for object assignment expression (#1583)
+ - [deps] update `confusing-browser-globals`, `eslint-plugin-import`, `tape`, `babel-preset-airbnb`
+ - [dev deps] update babel-related deps to latest
+ - [dev deps] update `eslint-find-rules`, `eslint-plugin-import`
+ - [tests] only run tests in non-lint per-package travis job
+ - [tests] use `eclint` instead of `editorconfig-tools`
+
+13.2.0 / 2019-07-01
+==================
+ - [minor] Enforce dangling underscores in method names (#1907)
+ - [fix] disable `no-var` in legacy entry point
+ - [patch] Ignore property modifications of `staticContext` params (#2029)
+ - [patch] `no-extraneous-dependencies`: Add jest.setup.js to devDeps (#1998)
+ - [meta] add disabled `prefer-named-capture-group` rule
+ - [meta] add disabled `no-useless-catch` config
+ - [deps] Switch to confusing-browser-globals (#1961)
+ - [deps] update `object.entries`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y`, `eslint-plugin-react`, `tape`
+ - [docs] correct JavaScript capitalization (#2046)
+ - [readme] Improve eslint config setup instructions for yarn (#2001)
+ - [docs] fix docs for whitespace config (#1914, #1871)
+
+13.1.0 / 2018-08-13
+==================
+ - [new] add eslint v5 support (#1834)
+ - [deps] update `eslint-plugin-import`, `eslint`, `babel-preset-airbnb`, `safe-publish-latest`, `eslint-find-rules`
+ - [docs] fix typo in readme (#1855)
+ - [new] update base ecmaVersion to 2018; remove deprecated experimentalObjectRestSpread option
+
+13.0.0 / 2018-06-21
+==================
+ - [breaking] order of import statements is ignored for unassigned imports (#1782)
+ - [breaking] enable `import/no-cycle`: warn on cyclical dependencies (#1779)
+ - [breaking] Change import/no-self-import from "off" to "error" (#1770)
+ - [breaking] Update `object-curly-newline` to match eslint 4.18.0 (#1761)
+ - [breaking] enable `no-useless-path-segments` (#1743)
+ - [breaking] Prevent line breaks before and after `=` (#1710)
+ - [breaking] Add .mjs extension support (#1634)
+ - [breaking] enable `implicit-arrow-linebreak`
+ - [breaking] Enables `nonblock-statement-body-position` rule and adds link to guide (#1618)
+ - [breaking] `no-mixed-operators`: only warn on `**` and `%` mixed with arithmetic operators; removes violation against mixing common math operators. (#1611)
+ - [breaking] `import/named`: enable
+ - [breaking] `lines-between-class-members`: set to “always”
+ - [breaking] `no-else-return`: disallow else-if (#1595)
+ - [breaking] Enables eslint rule for operator-linebreak
+ - [new] Adds config entry point with only whitespace rules enabled (#1749, #1751)
+ - [minor] only allow one newline at the end (#1794)
+ - [patch] Adjust imports for vue-cli (#1809)
+ - [patch] Allow devDependencies for `foo_spec.js` naming style (#1732)
+ - [patch] `function-paren-newline`: change to "consistent"
+ - [patch] avoid `__mocks__` `no-extraneous-dependencies` check (#1772)
+ - [patch] Include 'accumulator' exception for `no-param-reassign` (#1768)
+ - [patch] Set import/extensions to ignorePackages (#1652)
+ - [patch] properly ignore indentation on jsx
+ - [patch] `array-callback-return`: enable `allowImplicit` option (#1668)
+ - [deps] update `eslint`, `eslint-plugin-import`
+ - [dev deps] update `babel-preset-airbnb`, `tape`, `eslint-find-rules`
+ - [meta] add ES2015-2018 in npm package keywords (#1587)
+ - [meta] Add licenses to sub packages (#1746)
+ - [docs] add `npx` shortcut (#1694)
+ - [docs] Use HTTPS for links to ESLint documentation (#1628)
+ - [tests] ensure all entry points parse
+
+12.1.0 / 2017-10-16
+==================
+ - [deps] update `eslint` to `v4.9`
+
+12.0.2 / 2017-10-05
+==================
+ - [deps] update `eslint`
+
+12.0.1 / 2017-09-27
+==================
+ - [fix] ensure all JSX elements are ignored by `indent` (#1569)
+ - [deps] update `eslint`
+
+12.0.0 / 2017-09-02
+==================
+ - [deps] [breaking] require `eslint` v4
+   - enable `function-paren-newline`, `for-direction`, `getter-return`, `no-compare-neg-zero`, `semi-style`, `object-curly-newline`, `no-buffer-constructor`, `no-restricted-globals`, `switch-colon-spacing`, `template-tag-spacing`, `prefer-promise-reject-errors`, `prefer-destructuring`
+   - improve `indent`, `no-multi-spaces`, `no-trailing-spaces`, `no-underscore-dangle`
+ - [breaking] move `comma-dangle` to Stylistic Issues (#1514)
+ - [breaking] Rules prohibiting global isNaN, isFinite (#1477)
+ - [patch] also disallow padding in classes and switches (#1403)
+ - [patch] support Protractor config files in import/no-extraneous-dependencies (#1543)
+
+11.3.2 / 2017-08-22
+==================
+ - [patch] Add jest.config.js to import/no-extraneous-dependencies devDeps (#1522)
+ - [patch] Improve Gruntfile glob pattern (#1503)
+ - [deps] update `eslint` v4, `tape`
+ - [docs] Specify yarn-specific install instructions (#1511)
+
+11.3.1 / 2017-07-24
+==================
+ - [fix] `legacy`: remove top-level `ecmaFeatures`
+
+11.3.0 / 2017-07-23
+==================
+ - [deps] allow eslint v3 or v4 (#1447)
+ - [deps] update `eslint-plugin-import`
+ - [minor] Balanced spacing for inline block comments (#1440)
+ - [minor] `no-return-assign`: strengthen linting against returning assignments
+ - [patch] Allow jsx extensions for test files (#1427)
+ - [patch] `no-restricted-globals`: add confusing globals; leave disabled for now (#1420)
+ - [patch] Support Protractor config files in import/no-extraneous-dependencies (#1456)
+ - [docs] Remove TODO in prefer-reflect as it's deprecated (#1452)
+ - [docs] add yarn instructions (#1463, #1464)
+
+11.2.0 / 2017-05-14
+==================
+ - [minor] Disallow unused global variables
+
+11.1.3 / 2017-04-03
+==================
+ - [patch] add error messages to `no-restricted-syntax` (#1353)
+ - [deps] update `eslint`
+
+11.1.2 / 2017-03-25
+==================
+ - [patch] `no-param-reassign`: add ignorePropertyModificationsFor (#1325)
+ - [deps] update `eslint`
+
+11.1.1 / 2017-03-03
+==================
+ - [deps] update `eslint`
+ - [patch] enable `ignoreRestSiblings` in `no-unused-vars`
+
+11.1.0 / 2017-01-08
+==================
+ - [minor] enable `no-multi-assign`
+ - [deps] update `eslint`, `babel-preset-airbnb`
+ - Update a deprecated option (`eqeqeq`) (#1244)
+
+11.0.1 / 2017-01-08
+==================
+ - [deps] update `eslint`
+ - [docs] add note about `install-peerdeps` (#1234)
+ - [docs] Updated instructions to support non-bash users (#1214)
+
+11.0.0 / 2016-12-11
+==================
+ - [breaking] enable `no-await-in-loop`
+ - [patch]  disable `no-duplicate-imports` rule (#1188, #1195, #1054)
+ - [patch] `import/no-extraneous-dependencies`: add some comments to ignore patterns
+ - [patch] add `import/no-extraneous-dependencies` ignore patterns for test files (#1174)
+ - [patch] `import/no-extraneous-dependencies`: added ignore patterns for config files (#1168)
+ - [deps] update `eslint`, `eslint-plugin-import`, `tape`
+
+10.0.1 / 2016-11-07
+==================
+ - [fix] legacy config should not require `**`
+
+10.0.0 / 2016-11-06
+==================
+ - [breaking] prefer `**` over `Math.pow`
+ - [breaking] `comma-dangle`: require trailing commas for functions
+ - [breaking] enable `no-useless-return`
+ - [breaking] tighten up `indent`
+ - [breaking] tighten up `spaced-comment`
+ - [breaking] enable `import/no-named-default`
+ - [patch] loosen `max-len` with `ignoreRegExpLiterals` option
+ - [patch] loosen `no-extraneous-dependencies` for test files (#959, #1089)
+ - [deps] update `eslint`, `eslint-plugin-import`
+ - [dev deps] update `eslint-find-rules`
+ - [Tests] on `node` `v7`
+
+9.0.0 / 2016-10-16
+==================
+ - [breaking] Add `ForOfStatement` to `no-restricted-syntax` (#1122, #1134)
+ - [breaking] enable `import/no-webpack-loader-syntax` (#1123)
+ - [breaking] [deps] update `eslint` to `v3.8.0` (#1132)
+ - [breaking] [deps] update `eslint-plugin-import` to v2 (#1101)
+ - [patch] `new-cap`: add immutable.js exceptions
+ - [docs] ensure latest version of config is installed
+ - [dev deps] update `babel-preset-airbnb`, `eslint`, `eslint-find-rules`, `tape`, `safe-publish-latest`
+
+8.0.0 / 2016-09-24
+==================
+ - [breaking] enable rules: `no-restricted-properties`, `prefer-numeric-literals`, `lines-around-directive`, `import/extensions`, `import/no-absolute-path`, `import/no-dynamic-require`
+
+7.2.0 / 2016-09-23
+==================
+ - [new] set `ecmaVersion` to 2017; enable object rest/spread; update `babel-preset-airbnb`
+ - [patch] fix category of `no-restricted-properties`
+ - [deps] update `eslint`, `eslint-plugin-import`, `eslint-find-rules`, `safe-publish-latest`
+
+7.1.0 / 2016-09-11
+==================
+ - [minor] enable `arrow-parens` rule
+
+7.0.1 / 2016-09-10
+==================
+ - [patch] loosen `max-len` by ignoring strings
+ - [deps] update to `eslint` `v3.5.0`
+
+7.0.0 / 2016-09-06
+==================
+ - [breaking] Add no-plusplus in style.js and added explanation in README (#1012)
+
+6.0.0 / 2016-09-06
+==================
+ - [breaking] `valid-typeof`: enable `requireStringLiterals` option
+ - [breaking] enable `class-methods-use-this`
+ - [breaking] enable `symbol-description`
+ - [breaking] enable `no-bitwise`
+ - [breaking] enable `no-tabs`
+ - [breaking] enable `func-call-spacing`
+ - [breaking] enable `no-template-curly-in-string`
+ - [patch] remove redundant `DebuggerStatement` from `no-restricted-syntax` (#1031)
+ - [deps] update `eslint`, `eslint-find-rules`, `eslint-plugin-import`
+ - Update `ecmaVersion` to `2016`
+
+5.0.3 / 2016-08-21
+==================
+ - [fix] correct `import/extensions` list (#1013)
+ - [refactor] Changed ESLint rule configs to use 'off', 'warn', and 'error' instead of numbers for better readability (#946)
+ - [deps] update `eslint`, `eslint-plugin-react`
+
+5.0.2 / 2016-08-12
+==================
+ - [deps] update `eslint`, `eslint-find-rules`, `eslint-plugin-import`
+ - [tests] add `safe-publish-latest` to `prepublish`
+
 5.0.1 / 2016-07-29
 ==================
  - [patch] `no-unused-expressions`: flesh out options

packages/eslint-config-airbnb-base/LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2012 Airbnb
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/eslint-config-airbnb-base/README.md

@@ -2,7 +2,7 @@
 
 [![npm version](https://badge.fury.io/js/eslint-config-airbnb-base.svg)](http://badge.fury.io/js/eslint-config-airbnb-base)
 
-This package provides Airbnb's base JS .eslintrc as an extensible shared config.
+This package provides Airbnb's base JS .eslintrc (without React plugins) as an extensible shared config.
 
 ## Usage
 
@@ -12,27 +12,63 @@ We export two ESLint configurations for your usage.
 
 Our default export contains all of our ESLint rules, including ECMAScript 6+. It requires `eslint` and `eslint-plugin-import`.
 
-1. Ensure packages are installed with correct version numbers by running:
+1. Install the correct versions of each package, which are listed by the command:
+
+  ```sh
+  npm info "eslint-config-airbnb-base@latest" peerDependencies
+  ```
+
+  If using **npm 5+**, use this shortcut
+
+  ```sh
+  npx install-peerdeps --dev eslint-config-airbnb-base
+  ```
+
+  If using **yarn**, you can also use the shortcut described above if you have npm 5+ installed on your machine, as the command will detect that you are using yarn and will act accordingly.
+  Otherwise, run `npm info "eslint-config-airbnb-base@latest" peerDependencies` to list the peer dependencies and versions, then run `yarn add --dev <dependency>@<version>` for each listed peer dependency.
+
+
+  If using **npm < 5**, Linux/OSX users can run
+
   ```sh
   (
     export PKG=eslint-config-airbnb-base;
-    npm info "$PKG" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install --save-dev "$PKG"
+    npm info "$PKG@latest" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install --save-dev "$PKG@latest"
   )
   ```
 
   Which produces and runs a command like:
 
   ```sh
-    npm install --save-dev eslint-config-airbnb-base eslint@^3.0.1 eslint-plugin-import@^1.10.3
+    npm install --save-dev eslint-config-airbnb-base eslint@^#.#.# eslint-plugin-import@^#.#.#
   ```
 
-2. Add `"extends": "airbnb-base"` to your .eslintrc
+  If using **npm < 5**, Windows users can either install all the peer dependencies manually, or use the [install-peerdeps](https://github.com/nathanhleung/install-peerdeps) cli tool.
+
+  ```sh
+  npm install -g install-peerdeps
+  install-peerdeps --dev eslint-config-airbnb-base
+  ```
+
+  The cli will produce and run a command like:
+
+  ```sh
+  npm install --save-dev eslint-config-airbnb-base eslint@^#.#.# eslint-plugin-import@^#.#.#
+  ```
+
+2. Add `"extends": "airbnb-base"` to your .eslintrc.
 
 ### eslint-config-airbnb-base/legacy
 
 Lints ES5 and below. Requires `eslint` and `eslint-plugin-import`.
 
-1. Ensure packages are installed with correct version numbers by running:
+1. Install the correct versions of each package, which are listed by the command:
+
+  ```sh
+  npm info "eslint-config-airbnb-base@latest" peerDependencies
+  ```
+
+  Linux/OSX users can run
   ```sh
   (
     export PKG=eslint-config-airbnb-base;
@@ -48,7 +84,11 @@ Lints ES5 and below. Requires `eslint` and `eslint-plugin-import`.
 
 2. Add `"extends": "airbnb-base/legacy"` to your .eslintrc
 
-See [Airbnb's overarching ESLint config](https://npmjs.com/eslint-config-airbnb), [Airbnb's Javascript styleguide](https://github.com/airbnb/javascript), and the [ESlint config docs](http://eslint.org/docs/user-guide/configuring#extending-configuration-files) for more information.
+See [Airbnb's overarching ESLint config](https://npmjs.com/eslint-config-airbnb), [Airbnb's JavaScript styleguide](https://github.com/airbnb/javascript), and the [ESlint config docs](https://eslint.org/docs/user-guide/configuring#extending-configuration-files) for more information.
+
+### eslint-config-airbnb-base/whitespace
+
+This entry point only errors on whitespace rules and sets all other rules to warnings. View the list of whitespace rules [here](https://github.com/airbnb/javascript/blob/master/packages/eslint-config-airbnb-base/whitespace.js).
 
 ## Improving this config
 

packages/eslint-config-airbnb-base/index.js

@@ -7,12 +7,11 @@ module.exports = {
     './rules/variables',
     './rules/es6',
     './rules/imports',
+    './rules/strict',
   ].map(require.resolve),
   parserOptions: {
-    ecmaVersion: 7,
+    ecmaVersion: 2018,
     sourceType: 'module',
   },
-  rules: {
-    strict: 2,
-  }
+  rules: {},
 };

packages/eslint-config-airbnb-base/legacy.js

@@ -13,9 +13,22 @@ module.exports = {
     mocha: false,
     jasmine: false
   },
-  ecmaFeatures: {},
-  globals: {},
   rules: {
-    'comma-dangle': [2, 'never']
+    'comma-dangle': ['error', 'never'],
+    'prefer-numeric-literals': 'off',
+    'no-restricted-properties': ['error', {
+      object: 'arguments',
+      property: 'callee',
+      message: 'arguments.callee is deprecated',
+    }, {
+      property: '__defineGetter__',
+      message: 'Please use Object.defineProperty instead.',
+    }, {
+      property: '__defineSetter__',
+      message: 'Please use Object.defineProperty instead.',
+    }],
+    'no-var': 'off',
+    'prefer-object-spread': 'off',
+    strict: ['error', 'safe'],
   }
 };

packages/eslint-config-airbnb-base/package.json

@@ -1,15 +1,19 @@
 {
   "name": "eslint-config-airbnb-base",
-  "version": "5.0.1",
+  "version": "14.2.0",
   "description": "Airbnb's base JS ESLint config, following our styleguide",
   "main": "index.js",
   "scripts": {
-    "lint": "eslint .",
+    "prelint": "eclint check * rules/* test/*",
+    "lint": "eslint --report-unused-disable-directives .",
+    "pretests-only": "node ./test/requires",
     "tests-only": "babel-tape-runner ./test/test-*.js",
-    "prepublish": "(in-install || eslint-find-rules --unused) && (not-in-publish || npm test)",
+    "prepublish": "(in-install || eslint-find-rules --unused) && (not-in-publish || npm test) && safe-publish-latest",
     "pretest": "npm run --silent lint",
     "test": "npm run --silent tests-only",
-    "travis": "npm run --silent test"
+    "pretravis": ":",
+    "travis": "npm run --silent tests-only",
+    "posttravis": ":"
   },
   "repository": {
     "type": "git",
@@ -21,7 +25,11 @@
     "config",
     "airbnb",
     "javascript",
-    "styleguide"
+    "styleguide",
+    "es2015",
+    "es2016",
+    "es2017",
+    "es2018"
   ],
   "author": "Jake Teton-Landis (https://twitter.com/@jitl)",
   "contributors": [
@@ -45,19 +53,27 @@
   },
   "homepage": "https://github.com/airbnb/javascript",
   "devDependencies": {
-    "babel-preset-airbnb": "^2.0.0",
-    "babel-tape-runner": "^2.0.1",
-    "eslint": "^3.2.0",
-    "eslint-find-rules": "^1.11.1",
-    "eslint-plugin-import": "^1.12.0",
-    "in-publish": "^2.0.0",
-    "tape": "^4.6.0"
+    "@babel/runtime": "^7.8.7",
+    "babel-preset-airbnb": "^4.5.0",
+    "babel-tape-runner": "^3.0.0",
+    "eclint": "^2.8.1",
+    "eslint": "^5.16.0 || ^6.8.0 || ^7.2.0",
+    "eslint-find-rules": "^3.5.0",
+    "eslint-plugin-import": "^2.21.2",
+    "in-publish": "^2.0.1",
+    "safe-publish-latest": "^1.1.4",
+    "tape": "^5.0.1"
   },
   "peerDependencies": {
-    "eslint": "^3.2.0",
-    "eslint-plugin-import": "^1.12.0"
+    "eslint": "^5.16.0 || ^6.8.0 || ^7.2.0",
+    "eslint-plugin-import": "^2.21.2"
   },
   "engines": {
-    "node": ">= 4"
+    "node": ">= 6"
+  },
+  "dependencies": {
+    "confusing-browser-globals": "^1.0.9",
+    "object.assign": "^4.1.0",
+    "object.entries": "^1.1.2"
   }
 }

packages/eslint-config-airbnb-base/rules/best-practices.js

@@ -1,61 +1,91 @@
 module.exports = {
   rules: {
     // enforces getter/setter pairs in objects
-    'accessor-pairs': 0,
+    'accessor-pairs': 'off',
 
     // enforces return statements in callbacks of array's methods
-    // http://eslint.org/docs/rules/array-callback-return
-    'array-callback-return': 2,
+    // https://eslint.org/docs/rules/array-callback-return
+    'array-callback-return': ['error', { allowImplicit: true }],
 
     // treat var statements as if they were block scoped
-    'block-scoped-var': 2,
+    'block-scoped-var': 'error',
 
     // specify the maximum cyclomatic complexity allowed in a program
-    complexity: [0, 11],
+    complexity: ['off', 11],
+
+    // enforce that class methods use "this"
+    // https://eslint.org/docs/rules/class-methods-use-this
+    'class-methods-use-this': ['error', {
+      exceptMethods: [],
+    }],
 
     // require return statements to either always or never specify values
-    'consistent-return': 2,
+    'consistent-return': 'error',
 
     // specify curly brace conventions for all control statements
-    curly: [2, 'multi-line'],
+    curly: ['error', 'multi-line'], // multiline
 
     // require default case in switch statements
-    'default-case': [2, { commentPattern: '^no default$' }],
+    'default-case': ['error', { commentPattern: '^no default$' }],
+
+    // Enforce default clauses in switch statements to be last
+    // https://eslint.org/docs/rules/default-case-last
+    // TODO: enable, semver-minor, when eslint v7 is required (which is a major)
+    'default-case-last': 'off',
+
+    // https://eslint.org/docs/rules/default-param-last
+    // TODO: enable, semver-minor, when eslint v6.4 is required (which is a major)
+    'default-param-last': 'off',
 
     // encourages use of dot notation whenever possible
-    'dot-notation': [2, { allowKeywords: true }],
+    'dot-notation': ['error', { allowKeywords: true }],
 
     // enforces consistent newlines before or after dots
-    // http://eslint.org/docs/rules/dot-location
-    'dot-location': [2, 'property'],
+    // https://eslint.org/docs/rules/dot-location
+    'dot-location': ['error', 'property'],
 
     // require the use of === and !==
-    // http://eslint.org/docs/rules/eqeqeq
-    eqeqeq: [2, 'allow-null'],
+    // https://eslint.org/docs/rules/eqeqeq
+    eqeqeq: ['error', 'always', { null: 'ignore' }],
+
+    // Require grouped accessor pairs in object literals and classes
+    // https://eslint.org/docs/rules/grouped-accessor-pairs
+    // TODO: enable in next major, altho the guide forbids getters/setters anyways
+    'grouped-accessor-pairs': 'off',
 
     // make sure for-in loops have an if statement
-    'guard-for-in': 2,
+    'guard-for-in': 'error',
+
+    // enforce a maximum number of classes per file
+    // https://eslint.org/docs/rules/max-classes-per-file
+    'max-classes-per-file': ['error', 1],
 
     // disallow the use of alert, confirm, and prompt
-    'no-alert': 1,
+    'no-alert': 'warn',
 
     // disallow use of arguments.caller or arguments.callee
-    'no-caller': 2,
+    'no-caller': 'error',
 
     // disallow lexical declarations in case/default clauses
-    // http://eslint.org/docs/rules/no-case-declarations.html
-    'no-case-declarations': 2,
+    // https://eslint.org/docs/rules/no-case-declarations.html
+    'no-case-declarations': 'error',
+
+    // Disallow returning value in constructor
+    // https://eslint.org/docs/rules/no-constructor-return
+    // TODO: enable, semver-major
+    'no-constructor-return': 'off',
 
     // disallow division operators explicitly at beginning of regular expression
-    // http://eslint.org/docs/rules/no-div-regex
-    'no-div-regex': 0,
+    // https://eslint.org/docs/rules/no-div-regex
+    'no-div-regex': 'off',
 
     // disallow else after a return in an if
-    'no-else-return': 2,
+    // https://eslint.org/docs/rules/no-else-return
+    'no-else-return': ['error', { allowElseIf: false }],
 
     // disallow empty functions, except for standalone funcs/arrows
-    // http://eslint.org/docs/rules/no-empty-function
-    'no-empty-function': [2, {
+    // https://eslint.org/docs/rules/no-empty-function
+    'no-empty-function': ['error', {
       allow: [
         'arrowFunctions',
         'functions',
@@ -64,34 +94,40 @@ module.exports = {
     }],
 
     // disallow empty destructuring patterns
-    // http://eslint.org/docs/rules/no-empty-pattern
-    'no-empty-pattern': 2,
+    // https://eslint.org/docs/rules/no-empty-pattern
+    'no-empty-pattern': 'error',
 
     // disallow comparisons to null without a type-checking operator
-    'no-eq-null': 0,
+    'no-eq-null': 'off',
 
     // disallow use of eval()
-    'no-eval': 2,
+    'no-eval': 'error',
 
     // disallow adding to native types
-    'no-extend-native': 2,
+    'no-extend-native': 'error',
 
     // disallow unnecessary function binding
-    'no-extra-bind': 2,
+    'no-extra-bind': 'error',
 
     // disallow Unnecessary Labels
-    // http://eslint.org/docs/rules/no-extra-label
-    'no-extra-label': 2,
+    // https://eslint.org/docs/rules/no-extra-label
+    'no-extra-label': 'error',
 
     // disallow fallthrough of case statements
-    'no-fallthrough': 2,
+    'no-fallthrough': 'error',
 
     // disallow the use of leading or trailing decimal points in numeric literals
-    'no-floating-decimal': 2,
+    'no-floating-decimal': 'error',
+
+    // disallow reassignments of native objects or read-only globals
+    // https://eslint.org/docs/rules/no-global-assign
+    'no-global-assign': ['error', { exceptions: [] }],
+    // deprecated in favor of no-global-assign
+    'no-native-reassign': 'off',
 
     // disallow implicit type conversions
-    // http://eslint.org/docs/rules/no-implicit-coercion
-    'no-implicit-coercion': [0, {
+    // https://eslint.org/docs/rules/no-implicit-coercion
+    'no-implicit-coercion': ['off', {
       boolean: false,
       number: true,
       string: true,
@@ -99,30 +135,30 @@ module.exports = {
     }],
 
     // disallow var and named functions in global scope
-    // http://eslint.org/docs/rules/no-implicit-globals
-    'no-implicit-globals': 0,
+    // https://eslint.org/docs/rules/no-implicit-globals
+    'no-implicit-globals': 'off',
 
     // disallow use of eval()-like methods
-    'no-implied-eval': 2,
+    'no-implied-eval': 'error',
 
     // disallow this keywords outside of classes or class-like objects
-    'no-invalid-this': 0,
+    'no-invalid-this': 'off',
 
     // disallow usage of __iterator__ property
-    'no-iterator': 2,
+    'no-iterator': 'error',
 
     // disallow use of labels for anything other then loops and switches
-    'no-labels': [2, { allowLoop: false, allowSwitch: false }],
+    'no-labels': ['error', { allowLoop: false, allowSwitch: false }],
 
     // disallow unnecessary nested blocks
-    'no-lone-blocks': 2,
+    'no-lone-blocks': 'error',
 
     // disallow creation of functions within loops
-    'no-loop-func': 2,
+    'no-loop-func': 'error',
 
     // disallow magic numbers
-    // http://eslint.org/docs/rules/no-magic-numbers
-    'no-magic-numbers': [0, {
+    // https://eslint.org/docs/rules/no-magic-numbers
+    'no-magic-numbers': ['off', {
       ignore: [],
       ignoreArrayIndexes: true,
       enforceConst: true,
@@ -130,106 +166,196 @@ module.exports = {
     }],
 
     // disallow use of multiple spaces
-    'no-multi-spaces': 2,
+    'no-multi-spaces': ['error', {
+      ignoreEOLComments: false,
+    }],
 
     // disallow use of multiline strings
-    'no-multi-str': 2,
-
-    // disallow reassignments of native objects
-    'no-native-reassign': 2,
+    'no-multi-str': 'error',
 
     // disallow use of new operator when not part of the assignment or comparison
-    'no-new': 2,
+    'no-new': 'error',
 
     // disallow use of new operator for Function object
-    'no-new-func': 2,
+    'no-new-func': 'error',
 
     // disallows creating new instances of String, Number, and Boolean
-    'no-new-wrappers': 2,
+    'no-new-wrappers': 'error',
 
     // disallow use of (old style) octal literals
-    'no-octal': 2,
+    'no-octal': 'error',
 
     // disallow use of octal escape sequences in string literals, such as
     // var foo = 'Copyright \251';
-    'no-octal-escape': 2,
+    'no-octal-escape': 'error',
 
     // disallow reassignment of function parameters
-    // disallow parameter object manipulation
-    // rule: http://eslint.org/docs/rules/no-param-reassign.html
-    'no-param-reassign': [2, { props: true }],
+    // disallow parameter object manipulation except for specific exclusions
+    // rule: https://eslint.org/docs/rules/no-param-reassign.html
+    'no-param-reassign': ['error', {
+      props: true,
+      ignorePropertyModificationsFor: [
+        'acc', // for reduce accumulators
+        'accumulator', // for reduce accumulators
+        'e', // for e.returnvalue
+        'ctx', // for Koa routing
+        'context', // for Koa routing
+        'req', // for Express requests
+        'request', // for Express requests
+        'res', // for Express responses
+        'response', // for Express responses
+        '$scope', // for Angular 1 scopes
+        'staticContext', // for ReactRouter context
+      ]
+    }],
 
     // disallow usage of __proto__ property
-    'no-proto': 2,
+    'no-proto': 'error',
 
     // disallow declaring the same variable more then once
-    'no-redeclare': 2,
+    'no-redeclare': 'error',
+
+    // disallow certain object properties
+    // https://eslint.org/docs/rules/no-restricted-properties
+    'no-restricted-properties': ['error', {
+      object: 'arguments',
+      property: 'callee',
+      message: 'arguments.callee is deprecated',
+    }, {
+      object: 'global',
+      property: 'isFinite',
+      message: 'Please use Number.isFinite instead',
+    }, {
+      object: 'self',
+      property: 'isFinite',
+      message: 'Please use Number.isFinite instead',
+    }, {
+      object: 'window',
+      property: 'isFinite',
+      message: 'Please use Number.isFinite instead',
+    }, {
+      object: 'global',
+      property: 'isNaN',
+      message: 'Please use Number.isNaN instead',
+    }, {
+      object: 'self',
+      property: 'isNaN',
+      message: 'Please use Number.isNaN instead',
+    }, {
+      object: 'window',
+      property: 'isNaN',
+      message: 'Please use Number.isNaN instead',
+    }, {
+      property: '__defineGetter__',
+      message: 'Please use Object.defineProperty instead.',
+    }, {
+      property: '__defineSetter__',
+      message: 'Please use Object.defineProperty instead.',
+    }, {
+      object: 'Math',
+      property: 'pow',
+      message: 'Use the exponentiation operator (**) instead.',
+    }],
 
     // disallow use of assignment in return statement
-    'no-return-assign': 2,
+    'no-return-assign': ['error', 'always'],
+
+    // disallow redundant `return await`
+    'no-return-await': 'error',
 
     // disallow use of `javascript:` urls.
-    'no-script-url': 2,
+    'no-script-url': 'error',
 
     // disallow self assignment
-    // http://eslint.org/docs/rules/no-self-assign
-    'no-self-assign': 2,
+    // https://eslint.org/docs/rules/no-self-assign
+    'no-self-assign': ['error', {
+      props: true,
+    }],
 
     // disallow comparisons where both sides are exactly the same
-    'no-self-compare': 2,
+    'no-self-compare': 'error',
 
     // disallow use of comma operator
-    'no-sequences': 2,
+    'no-sequences': 'error',
 
     // restrict what can be thrown as an exception
-    'no-throw-literal': 2,
+    'no-throw-literal': 'error',
 
     // disallow unmodified conditions of loops
-    // http://eslint.org/docs/rules/no-unmodified-loop-condition
-    'no-unmodified-loop-condition': 0,
+    // https://eslint.org/docs/rules/no-unmodified-loop-condition
+    'no-unmodified-loop-condition': 'off',
 
     // disallow usage of expressions in statement position
-    'no-unused-expressions': [2, {
+    'no-unused-expressions': ['error', {
       allowShortCircuit: false,
       allowTernary: false,
+      allowTaggedTemplates: false,
     }],
 
     // disallow unused labels
-    // http://eslint.org/docs/rules/no-unused-labels
-    'no-unused-labels': 2,
+    // https://eslint.org/docs/rules/no-unused-labels
+    'no-unused-labels': 'error',
 
     // disallow unnecessary .call() and .apply()
-    'no-useless-call': 0,
+    'no-useless-call': 'off',
+
+    // Disallow unnecessary catch clauses
+    // https://eslint.org/docs/rules/no-useless-catch
+    'no-useless-catch': 'error',
 
     // disallow useless string concatenation
-    // http://eslint.org/docs/rules/no-useless-concat
-    'no-useless-concat': 2,
+    // https://eslint.org/docs/rules/no-useless-concat
+    'no-useless-concat': 'error',
 
     // disallow unnecessary string escaping
-    // http://eslint.org/docs/rules/no-useless-escape
-    'no-useless-escape': 2,
+    // https://eslint.org/docs/rules/no-useless-escape
+    'no-useless-escape': 'error',
+
+    // disallow redundant return; keywords
+    // https://eslint.org/docs/rules/no-useless-return
+    'no-useless-return': 'error',
 
     // disallow use of void operator
-    // http://eslint.org/docs/rules/no-void
-    'no-void': 2,
+    // https://eslint.org/docs/rules/no-void
+    'no-void': 'error',
 
     // disallow usage of configurable warning terms in comments: e.g. todo
-    'no-warning-comments': [0, { terms: ['todo', 'fixme', 'xxx'], location: 'start' }],
+    'no-warning-comments': ['off', { terms: ['todo', 'fixme', 'xxx'], location: 'start' }],
 
     // disallow use of the with statement
-    'no-with': 2,
+    'no-with': 'error',
+
+    // require using Error objects as Promise rejection reasons
+    // https://eslint.org/docs/rules/prefer-promise-reject-errors
+    'prefer-promise-reject-errors': ['error', { allowEmptyReject: true }],
+
+    // Suggest using named capture group in regular expression
+    // https://eslint.org/docs/rules/prefer-named-capture-group
+    'prefer-named-capture-group': 'off',
+
+    // https://eslint.org/docs/rules/prefer-regex-literals
+    // TODO; enable, semver-minor, once eslint v6.4 is required (which is a major)
+    'prefer-regex-literals': 'off',
 
     // require use of the second argument for parseInt()
-    radix: 2,
+    radix: 'error',
+
+    // require `await` in `async function` (note: this is a horrible rule that should never be used)
+    // https://eslint.org/docs/rules/require-await
+    'require-await': 'off',
+
+    // Enforce the use of u flag on RegExp
+    // https://eslint.org/docs/rules/require-unicode-regexp
+    'require-unicode-regexp': 'off',
 
     // requires to declare all vars on top of their containing scope
-    'vars-on-top': 2,
+    'vars-on-top': 'error',
 
     // require immediate function invocation to be wrapped in parentheses
-    // http://eslint.org/docs/rules/wrap-iife.html
-    'wrap-iife': [2, 'outside'],
+    // https://eslint.org/docs/rules/wrap-iife.html
+    'wrap-iife': ['error', 'outside', { functionPrototypeMethods: false }],
 
     // require or disallow Yoda conditions
-    yoda: 2
+    yoda: 'error'
   }
 };

packages/eslint-config-airbnb-base/rules/errors.js

@@ -1,103 +1,165 @@
 module.exports = {
   rules: {
-    // require trailing commas in multiline object literals
-    'comma-dangle': [2, 'always-multiline'],
+    // Enforce “for” loop update clause moving the counter in the right direction
+    // https://eslint.org/docs/rules/for-direction
+    'for-direction': 'error',
+
+    // Enforces that a return statement is present in property getters
+    // https://eslint.org/docs/rules/getter-return
+    'getter-return': ['error', { allowImplicit: true }],
+
+    // disallow using an async function as a Promise executor
+    // https://eslint.org/docs/rules/no-async-promise-executor
+    'no-async-promise-executor': 'error',
+
+    // Disallow await inside of loops
+    // https://eslint.org/docs/rules/no-await-in-loop
+    'no-await-in-loop': 'error',
+
+    // Disallow comparisons to negative zero
+    // https://eslint.org/docs/rules/no-compare-neg-zero
+    'no-compare-neg-zero': 'error',
 
     // disallow assignment in conditional expressions
-    'no-cond-assign': [2, 'always'],
+    'no-cond-assign': ['error', 'always'],
 
     // disallow use of console
-    'no-console': 1,
+    'no-console': 'warn',
 
     // disallow use of constant expressions in conditions
-    'no-constant-condition': 1,
+    'no-constant-condition': 'warn',
 
     // disallow control characters in regular expressions
-    'no-control-regex': 2,
+    'no-control-regex': 'error',
 
     // disallow use of debugger
-    'no-debugger': 2,
+    'no-debugger': 'error',
 
     // disallow duplicate arguments in functions
-    'no-dupe-args': 2,
+    'no-dupe-args': 'error',
+
+    // Disallow duplicate conditions in if-else-if chains
+    // https://eslint.org/docs/rules/no-dupe-else-if
+    // TODO: enable, semver-major
+    'no-dupe-else-if': 'off',
 
     // disallow duplicate keys when creating object literals
-    'no-dupe-keys': 2,
+    'no-dupe-keys': 'error',
 
     // disallow a duplicate case label.
-    'no-duplicate-case': 2,
+    'no-duplicate-case': 'error',
 
     // disallow empty statements
-    'no-empty': 2,
+    'no-empty': 'error',
 
     // disallow the use of empty character classes in regular expressions
-    'no-empty-character-class': 2,
+    'no-empty-character-class': 'error',
 
     // disallow assigning to the exception in a catch block
-    'no-ex-assign': 2,
+    'no-ex-assign': 'error',
 
     // disallow double-negation boolean casts in a boolean context
-    // http://eslint.org/docs/rules/no-extra-boolean-cast
-    'no-extra-boolean-cast': 2,
+    // https://eslint.org/docs/rules/no-extra-boolean-cast
+    'no-extra-boolean-cast': 'error',
 
     // disallow unnecessary parentheses
-    // http://eslint.org/docs/rules/no-extra-parens
-    'no-extra-parens': [0, 'all', {
+    // https://eslint.org/docs/rules/no-extra-parens
+    'no-extra-parens': ['off', 'all', {
       conditionalAssign: true,
       nestedBinaryExpressions: false,
       returnAssign: false,
+      ignoreJSX: 'all', // delegate to eslint-plugin-react
+      enforceForArrowConditionals: false,
     }],
 
     // disallow unnecessary semicolons
-    'no-extra-semi': 2,
+    'no-extra-semi': 'error',
 
     // disallow overwriting functions written as function declarations
-    'no-func-assign': 2,
+    'no-func-assign': 'error',
+
+    // https://eslint.org/docs/rules/no-import-assign
+    // TODO: enable, semver-minor, once eslint v6.4 is required (which is a major)
+    'no-import-assign': 'off',
 
     // disallow function or variable declarations in nested blocks
-    'no-inner-declarations': 2,
+    'no-inner-declarations': 'error',
 
     // disallow invalid regular expression strings in the RegExp constructor
-    'no-invalid-regexp': 2,
+    'no-invalid-regexp': 'error',
 
     // disallow irregular whitespace outside of strings and comments
-    'no-irregular-whitespace': 2,
+    'no-irregular-whitespace': 'error',
 
-    // disallow negation of the left operand of an in expression
-    'no-negated-in-lhs': 2,
+    // Disallow Number Literals That Lose Precision
+    // https://eslint.org/docs/rules/no-loss-of-precision
+    // TODO: enable, semver-minor, once eslint v7.1 is required (which is major)
+    'no-loss-of-precision': 'off',
+
+    // Disallow characters which are made with multiple code points in character class syntax
+    // https://eslint.org/docs/rules/no-misleading-character-class
+    'no-misleading-character-class': 'error',
 
     // disallow the use of object properties of the global object (Math and JSON) as functions
-    'no-obj-calls': 2,
+    'no-obj-calls': 'error',
 
     // disallow use of Object.prototypes builtins directly
-    // http://eslint.org/docs/rules/no-prototype-builtins
-    'no-prototype-builtins': 2,
+    // https://eslint.org/docs/rules/no-prototype-builtins
+    'no-prototype-builtins': 'error',
 
     // disallow multiple spaces in a regular expression literal
-    'no-regex-spaces': 2,
+    'no-regex-spaces': 'error',
+
+    // Disallow returning values from setters
+    // https://eslint.org/docs/rules/no-setter-return
+    // TODO: enable, semver-major (altho the guide forbids getters/setters already)
+    'no-setter-return': 'off',
 
     // disallow sparse arrays
-    'no-sparse-arrays': 2,
+    'no-sparse-arrays': 'error',
+
+    // Disallow template literal placeholder syntax in regular strings
+    // https://eslint.org/docs/rules/no-template-curly-in-string
+    'no-template-curly-in-string': 'error',
 
     // Avoid code that looks like two expressions but is actually one
-    // http://eslint.org/docs/rules/no-unexpected-multiline
-    'no-unexpected-multiline': 2,
+    // https://eslint.org/docs/rules/no-unexpected-multiline
+    'no-unexpected-multiline': 'error',
 
     // disallow unreachable statements after a return, throw, continue, or break statement
-    'no-unreachable': 2,
+    'no-unreachable': 'error',
 
     // disallow return/throw/break/continue inside finally blocks
-    // http://eslint.org/docs/rules/no-unsafe-finally
-    'no-unsafe-finally': 2,
+    // https://eslint.org/docs/rules/no-unsafe-finally
+    'no-unsafe-finally': 'error',
+
+    // disallow negating the left operand of relational operators
+    // https://eslint.org/docs/rules/no-unsafe-negation
+    'no-unsafe-negation': 'error',
+
+    // Disallow useless backreferences in regular expressions
+    // https://eslint.org/docs/rules/no-useless-backreference
+    // TODO: enable, semver-minor, once eslint v7 is required (which is major)
+    'no-useless-backreference': 'off',
+
+    // disallow negation of the left operand of an in expression
+    // deprecated in favor of no-unsafe-negation
+    'no-negated-in-lhs': 'off',
+
+    // Disallow assignments that can lead to race conditions due to usage of await or yield
+    // https://eslint.org/docs/rules/require-atomic-updates
+    // note: not enabled because it is very buggy
+    'require-atomic-updates': 'off',
 
     // disallow comparisons with the value NaN
-    'use-isnan': 2,
+    'use-isnan': 'error',
 
     // ensure JSDoc comments are valid
-    // http://eslint.org/docs/rules/valid-jsdoc
-    'valid-jsdoc': 0,
+    // https://eslint.org/docs/rules/valid-jsdoc
+    'valid-jsdoc': 'off',
 
     // ensure that the results of typeof are compared against a valid string
-    'valid-typeof': 2
+    // https://eslint.org/docs/rules/valid-typeof
+    'valid-typeof': ['error', { requireStringLiterals: true }],
   }
 };

packages/eslint-config-airbnb-base/rules/es6.js

@@ -13,133 +13,174 @@ module.exports = {
 
   rules: {
     // enforces no braces where they can be omitted
-    // http://eslint.org/docs/rules/arrow-body-style
-    'arrow-body-style': [2, 'as-needed'],
+    // https://eslint.org/docs/rules/arrow-body-style
+    // TODO: enable requireReturnForObjectLiteral?
+    'arrow-body-style': ['error', 'as-needed', {
+      requireReturnForObjectLiteral: false,
+    }],
 
     // require parens in arrow function arguments
-    'arrow-parens': 0,
+    // https://eslint.org/docs/rules/arrow-parens
+    'arrow-parens': ['error', 'always'],
 
     // require space before/after arrow function's arrow
-    // http://eslint.org/docs/rules/arrow-spacing
-    'arrow-spacing': [2, { before: true, after: true }],
+    // https://eslint.org/docs/rules/arrow-spacing
+    'arrow-spacing': ['error', { before: true, after: true }],
 
     // verify super() callings in constructors
-    'constructor-super': 2,
+    'constructor-super': 'error',
 
     // enforce the spacing around the * in generator functions
-    // http://eslint.org/docs/rules/generator-star-spacing
-    'generator-star-spacing': [2, { before: false, after: true }],
+    // https://eslint.org/docs/rules/generator-star-spacing
+    'generator-star-spacing': ['error', { before: false, after: true }],
 
     // disallow modifying variables of class declarations
-    // http://eslint.org/docs/rules/no-class-assign
-    'no-class-assign': 2,
+    // https://eslint.org/docs/rules/no-class-assign
+    'no-class-assign': 'error',
 
     // disallow arrow functions where they could be confused with comparisons
-    // http://eslint.org/docs/rules/no-confusing-arrow
-    'no-confusing-arrow': [2, {
+    // https://eslint.org/docs/rules/no-confusing-arrow
+    'no-confusing-arrow': ['error', {
       allowParens: true,
     }],
 
     // disallow modifying variables that are declared using const
-    'no-const-assign': 2,
+    'no-const-assign': 'error',
 
     // disallow duplicate class members
-    // http://eslint.org/docs/rules/no-dupe-class-members
-    'no-dupe-class-members': 2,
+    // https://eslint.org/docs/rules/no-dupe-class-members
+    'no-dupe-class-members': 'error',
 
     // disallow importing from the same path more than once
-    // http://eslint.org/docs/rules/no-duplicate-imports
-    'no-duplicate-imports': 2,
+    // https://eslint.org/docs/rules/no-duplicate-imports
+    // replaced by https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-duplicates.md
+    'no-duplicate-imports': 'off',
 
     // disallow symbol constructor
-    // http://eslint.org/docs/rules/no-new-symbol
-    'no-new-symbol': 2,
+    // https://eslint.org/docs/rules/no-new-symbol
+    'no-new-symbol': 'error',
+
+    // Disallow specified names in exports
+    // https://eslint.org/docs/rules/no-restricted-exports
+    // TODO enable, semver-minor, once eslint v7 is required (which is major)
+    'no-restricted-exports': ['off', {
+      restrictedNamedExports: [
+        'default', // use `export default` to provide a default export
+        'then', // this will cause tons of confusion when your module is dynamically `import()`ed
+      ],
+    }],
 
     // disallow specific imports
-    // http://eslint.org/docs/rules/no-restricted-imports
-    'no-restricted-imports': 0,
+    // https://eslint.org/docs/rules/no-restricted-imports
+    'no-restricted-imports': ['off', {
+      paths: [],
+      patterns: []
+    }],
 
     // disallow to use this/super before super() calling in constructors.
-    // http://eslint.org/docs/rules/no-this-before-super
-    'no-this-before-super': 2,
+    // https://eslint.org/docs/rules/no-this-before-super
+    'no-this-before-super': 'error',
 
     // disallow useless computed property keys
-    // http://eslint.org/docs/rules/no-useless-computed-key
-    'no-useless-computed-key': 2,
+    // https://eslint.org/docs/rules/no-useless-computed-key
+    'no-useless-computed-key': 'error',
 
     // disallow unnecessary constructor
-    // http://eslint.org/docs/rules/no-useless-constructor
-    'no-useless-constructor': 2,
+    // https://eslint.org/docs/rules/no-useless-constructor
+    'no-useless-constructor': 'error',
 
     // disallow renaming import, export, and destructured assignments to the same name
-    // http://eslint.org/docs/rules/no-useless-rename
-    'no-useless-rename': [2, {
+    // https://eslint.org/docs/rules/no-useless-rename
+    'no-useless-rename': ['error', {
       ignoreDestructuring: false,
       ignoreImport: false,
       ignoreExport: false,
     }],
 
     // require let or const instead of var
-    'no-var': 2,
+    'no-var': 'error',
 
     // require method and property shorthand syntax for object literals
-    // http://eslint.org/docs/rules/object-shorthand
-    'object-shorthand': [2, 'always', {
+    // https://eslint.org/docs/rules/object-shorthand
+    'object-shorthand': ['error', 'always', {
       ignoreConstructors: false,
       avoidQuotes: true,
     }],
 
     // suggest using arrow functions as callbacks
-    'prefer-arrow-callback': [2, {
+    'prefer-arrow-callback': ['error', {
       allowNamedFunctions: false,
       allowUnboundThis: true,
     }],
 
     // suggest using of const declaration for variables that are never modified after declared
-    'prefer-const': [2, {
+    'prefer-const': ['error', {
       destructuring: 'any',
       ignoreReadBeforeAssign: true,
     }],
 
+    // Prefer destructuring from arrays and objects
+    // https://eslint.org/docs/rules/prefer-destructuring
+    'prefer-destructuring': ['error', {
+      VariableDeclarator: {
+        array: false,
+        object: true,
+      },
+      AssignmentExpression: {
+        array: true,
+        object: false,
+      },
+    }, {
+      enforceForRenamedProperties: false,
+    }],
+
+    // disallow parseInt() in favor of binary, octal, and hexadecimal literals
+    // https://eslint.org/docs/rules/prefer-numeric-literals
+    'prefer-numeric-literals': 'error',
+
     // suggest using Reflect methods where applicable
-    // http://eslint.org/docs/rules/prefer-reflect
-    // TODO: enable
-    'prefer-reflect': 0,
+    // https://eslint.org/docs/rules/prefer-reflect
+    'prefer-reflect': 'off',
 
     // use rest parameters instead of arguments
-    // http://eslint.org/docs/rules/prefer-rest-params
-    'prefer-rest-params': 2,
+    // https://eslint.org/docs/rules/prefer-rest-params
+    'prefer-rest-params': 'error',
 
     // suggest using the spread operator instead of .apply()
-    // http://eslint.org/docs/rules/prefer-spread
-    'prefer-spread': 2,
+    // https://eslint.org/docs/rules/prefer-spread
+    'prefer-spread': 'error',
 
     // suggest using template literals instead of string concatenation
-    // http://eslint.org/docs/rules/prefer-template
-    'prefer-template': 2,
+    // https://eslint.org/docs/rules/prefer-template
+    'prefer-template': 'error',
 
     // disallow generator functions that do not have yield
-    // http://eslint.org/docs/rules/require-yield
-    'require-yield': 2,
+    // https://eslint.org/docs/rules/require-yield
+    'require-yield': 'error',
 
     // enforce spacing between object rest-spread
-    // http://eslint.org/docs/rules/rest-spread-spacing
-    'rest-spread-spacing': [2, 'never'],
+    // https://eslint.org/docs/rules/rest-spread-spacing
+    'rest-spread-spacing': ['error', 'never'],
 
     // import sorting
-    // http://eslint.org/docs/rules/sort-imports
-    'sort-imports': [0, {
+    // https://eslint.org/docs/rules/sort-imports
+    'sort-imports': ['off', {
       ignoreCase: false,
+      ignoreDeclarationSort: false,
       ignoreMemberSort: false,
       memberSyntaxSortOrder: ['none', 'all', 'multiple', 'single'],
     }],
 
+    // require a Symbol description
+    // https://eslint.org/docs/rules/symbol-description
+    'symbol-description': 'error',
+
     // enforce usage of spacing in template strings
-    // http://eslint.org/docs/rules/template-curly-spacing
-    'template-curly-spacing': 2,
+    // https://eslint.org/docs/rules/template-curly-spacing
+    'template-curly-spacing': 'error',
 
     // enforce spacing around the * in yield* expressions
-    // http://eslint.org/docs/rules/yield-star-spacing
-    'yield-star-spacing': [2, 'after']
+    // https://eslint.org/docs/rules/yield-star-spacing
+    'yield-star-spacing': ['error', 'after']
   }
 };

packages/eslint-config-airbnb-base/rules/imports.js

@@ -13,11 +13,13 @@ module.exports = {
   settings: {
     'import/resolver': {
       node: {
-        extensions: ['.js', '.json']
+        extensions: ['.mjs', '.js', '.json']
       }
     },
     'import/extensions': [
-      'node_modules',
+      '.js',
+      '.mjs',
+      '.jsx',
     ],
     'import/core-modules': [
     ],
@@ -32,101 +34,229 @@ module.exports = {
 
     // ensure imports point to files/modules that can be resolved
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-unresolved.md
-    'import/no-unresolved': [2, { commonjs: true }],
+    'import/no-unresolved': ['error', { commonjs: true, caseSensitive: true }],
 
     // ensure named imports coupled with named exports
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/named.md#when-not-to-use-it
-    'import/named': 0,
+    'import/named': 'error',
 
     // ensure default import coupled with default export
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/default.md#when-not-to-use-it
-    'import/default': 0,
+    'import/default': 'off',
 
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/namespace.md
-    'import/namespace': 0,
+    'import/namespace': 'off',
 
     // Helpful warnings:
 
     // disallow invalid exports, e.g. multiple defaults
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/export.md
-    'import/export': 2,
+    'import/export': 'error',
 
     // do not allow a default import name to match a named export
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-named-as-default.md
-    'import/no-named-as-default': 2,
+    'import/no-named-as-default': 'error',
 
     // warn on accessing default export property names that are also named exports
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-named-as-default-member.md
-    'import/no-named-as-default-member': 2,
+    'import/no-named-as-default-member': 'error',
 
     // disallow use of jsdoc-marked-deprecated imports
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-deprecated.md
-    'import/no-deprecated': 0,
+    'import/no-deprecated': 'off',
 
     // Forbid the use of extraneous packages
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-extraneous-dependencies.md
-    'import/no-extraneous-dependencies': [2, {
-      devDependencies: false,
+    // paths are treated both as absolute paths, and relative to process.cwd()
+    'import/no-extraneous-dependencies': ['error', {
+      devDependencies: [
+        'test/**', // tape, common npm pattern
+        'tests/**', // also common npm pattern
+        'spec/**', // mocha, rspec-like pattern
+        '**/__tests__/**', // jest pattern
+        '**/__mocks__/**', // jest pattern
+        'test.{js,jsx}', // repos with a single test file
+        'test-*.{js,jsx}', // repos with multiple top-level test files
+        '**/*{.,_}{test,spec}.{js,jsx}', // tests where the extension or filename suffix denotes that it is a test
+        '**/jest.config.js', // jest config
+        '**/jest.setup.js', // jest setup
+        '**/vue.config.js', // vue-cli config
+        '**/webpack.config.js', // webpack config
+        '**/webpack.config.*.js', // webpack config
+        '**/rollup.config.js', // rollup config
+        '**/rollup.config.*.js', // rollup config
+        '**/gulpfile.js', // gulp config
+        '**/gulpfile.*.js', // gulp config
+        '**/Gruntfile{,.js}', // grunt config
+        '**/protractor.conf.js', // protractor config
+        '**/protractor.conf.*.js', // protractor config
+        '**/karma.conf.js' // karma config
+      ],
       optionalDependencies: false,
     }],
 
     // Forbid mutable exports
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-mutable-exports.md
-    'import/no-mutable-exports': 2,
+    'import/no-mutable-exports': 'error',
 
     // Module systems:
 
     // disallow require()
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-commonjs.md
-    'import/no-commonjs': 0,
+    'import/no-commonjs': 'off',
 
     // disallow AMD require/define
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-amd.md
-    'import/no-amd': 2,
+    'import/no-amd': 'error',
 
     // No Node.js builtin modules
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-nodejs-modules.md
     // TODO: enable?
-    'import/no-nodejs-modules': 0,
+    'import/no-nodejs-modules': 'off',
 
     // Style guide:
 
+    // disallow non-import statements appearing before import statements
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/first.md
+    'import/first': 'error',
+
     // disallow non-import statements appearing before import statements
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/imports-first.md
-    'import/imports-first': [2, 'absolute-first'],
+    // deprecated: use `import/first`
+    'import/imports-first': 'off',
 
     // disallow duplicate imports
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-duplicates.md
-    'import/no-duplicates': 2,
+    'import/no-duplicates': 'error',
 
     // disallow namespace imports
     // TODO: enable?
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-namespace.md
-    'import/no-namespace': 0,
+    'import/no-namespace': 'off',
 
     // Ensure consistent use of file extension within the import path
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/extensions.md
-    // TODO: enable when https://github.com/benmosher/eslint-plugin-import/issues/390 is resolved
-    'import/extensions': [0, 'never'],
-
-    // Enforce a convention in module import order
-    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/order.md
-    // TODO: enable?
-    'import/order': [0, {
-      groups: ['builtin', 'external', 'internal', 'parent', 'sibling', 'index'],
-      'newlines-between': 'never',
+    'import/extensions': ['error', 'ignorePackages', {
+      js: 'never',
+      mjs: 'never',
+      jsx: 'never',
     }],
 
+    // ensure absolute imports are above relative imports and that unassigned imports are ignored
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/order.md
+    // TODO: enforce a stricter convention in module import order?
+    'import/order': ['error', { groups: [['builtin', 'external', 'internal']] }],
+
     // Require a newline after the last import/require in a group
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/newline-after-import.md
-    'import/newline-after-import': 2,
+    'import/newline-after-import': 'error',
 
     // Require modules with a single export to use a default export
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/prefer-default-export.md
-    'import/prefer-default-export': 2,
+    'import/prefer-default-export': 'error',
 
     // Restrict which files can be imported in a given folder
     // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-restricted-paths.md
-    'import/no-restricted-paths': 0,
+    'import/no-restricted-paths': 'off',
+
+    // Forbid modules to have too many dependencies
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/max-dependencies.md
+    'import/max-dependencies': ['off', { max: 10 }],
+
+    // Forbid import of modules using absolute paths
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-absolute-path.md
+    'import/no-absolute-path': 'error',
+
+    // Forbid require() calls with expressions
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-dynamic-require.md
+    'import/no-dynamic-require': 'error',
+
+    // prevent importing the submodules of other modules
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-internal-modules.md
+    'import/no-internal-modules': ['off', {
+      allow: [],
+    }],
+
+    // Warn if a module could be mistakenly parsed as a script by a consumer
+    // leveraging Unambiguous JavaScript Grammar
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/unambiguous.md
+    // this should not be enabled until this proposal has at least been *presented* to TC39.
+    // At the moment, it's not a thing.
+    'import/unambiguous': 'off',
+
+    // Forbid Webpack loader syntax in imports
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-webpack-loader-syntax.md
+    'import/no-webpack-loader-syntax': 'error',
+
+    // Prevent unassigned imports
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-unassigned-import.md
+    // importing for side effects is perfectly acceptable, if you need side effects.
+    'import/no-unassigned-import': 'off',
+
+    // Prevent importing the default as if it were named
+    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-named-default.md
+    'import/no-named-default': 'error',
+
+    // Reports if a module's default export is unnamed
+    // https://github.com/benmosher/eslint-plugin-import/blob/d9b712ac7fd1fddc391f7b234827925c160d956f/docs/rules/no-anonymous-default-export.md
+    'import/no-anonymous-default-export': ['off', {
+      allowArray: false,
+      allowArrowFunction: false,
+      allowAnonymousClass: false,
+      allowAnonymousFunction: false,
+      allowLiteral: false,
+      allowObject: false,
+    }],
+
+    // This rule enforces that all exports are declared at the bottom of the file.
+    // https://github.com/benmosher/eslint-plugin-import/blob/98acd6afd04dcb6920b81330114e146dc8532ea4/docs/rules/exports-last.md
+    // TODO: enable?
+    'import/exports-last': 'off',
+
+    // Reports when named exports are not grouped together in a single export declaration
+    // or when multiple assignments to CommonJS module.exports or exports object are present
+    // in a single file.
+    // https://github.com/benmosher/eslint-plugin-import/blob/44a038c06487964394b1e15b64f3bd34e5d40cde/docs/rules/group-exports.md
+    'import/group-exports': 'off',
+
+    // forbid default exports. this is a terrible rule, do not use it.
+    // https://github.com/benmosher/eslint-plugin-import/blob/44a038c06487964394b1e15b64f3bd34e5d40cde/docs/rules/no-default-export.md
+    'import/no-default-export': 'off',
+
+    // Prohibit named exports. this is a terrible rule, do not use it.
+    // https://github.com/benmosher/eslint-plugin-import/blob/1ec80fa35fa1819e2d35a70e68fb6a149fb57c5e/docs/rules/no-named-export.md
+    'import/no-named-export': 'off',
+
+    // Forbid a module from importing itself
+    // https://github.com/benmosher/eslint-plugin-import/blob/44a038c06487964394b1e15b64f3bd34e5d40cde/docs/rules/no-self-import.md
+    'import/no-self-import': 'error',
+
+    // Forbid cyclical dependencies between modules
+    // https://github.com/benmosher/eslint-plugin-import/blob/d81f48a2506182738409805f5272eff4d77c9348/docs/rules/no-cycle.md
+    'import/no-cycle': ['error', { maxDepth: Infinity }],
+
+    // Ensures that there are no useless path segments
+    // https://github.com/benmosher/eslint-plugin-import/blob/ebafcbf59ec9f653b2ac2a0156ca3bcba0a7cf57/docs/rules/no-useless-path-segments.md
+    'import/no-useless-path-segments': ['error', { commonjs: true }],
+
+    // dynamic imports require a leading comment with a webpackChunkName
+    // https://github.com/benmosher/eslint-plugin-import/blob/ebafcbf59ec9f653b2ac2a0156ca3bcba0a7cf57/docs/rules/dynamic-import-chunkname.md
+    'import/dynamic-import-chunkname': ['off', {
+      importFunctions: [],
+      webpackChunknameFormat: '[0-9a-zA-Z-_/.]+',
+    }],
+
+    // Use this rule to prevent imports to folders in relative parent paths.
+    // https://github.com/benmosher/eslint-plugin-import/blob/c34f14f67f077acd5a61b3da9c0b0de298d20059/docs/rules/no-relative-parent-imports.md
+    'import/no-relative-parent-imports': 'off',
+
+    // Reports modules without any exports, or with unused exports
+    // https://github.com/benmosher/eslint-plugin-import/blob/f63dd261809de6883b13b6b5b960e6d7f42a7813/docs/rules/no-unused-modules.md
+    // TODO: enable, semver-major
+    'import/no-unused-modules': ['off', {
+      ignoreExports: [],
+      missingExports: true,
+      unusedExports: true,
+    }],
   },
 };

packages/eslint-config-airbnb-base/rules/node.js

@@ -5,35 +5,39 @@ module.exports = {
 
   rules: {
     // enforce return after a callback
-    'callback-return': 0,
+    'callback-return': 'off',
 
     // require all requires be top-level
-    // http://eslint.org/docs/rules/global-require
-    'global-require': 2,
+    // https://eslint.org/docs/rules/global-require
+    'global-require': 'error',
 
     // enforces error handling in callbacks (node environment)
-    'handle-callback-err': 0,
+    'handle-callback-err': 'off',
+
+    // disallow use of the Buffer() constructor
+    // https://eslint.org/docs/rules/no-buffer-constructor
+    'no-buffer-constructor': 'error',
 
     // disallow mixing regular variable and require declarations
-    'no-mixed-requires': [0, false],
+    'no-mixed-requires': ['off', false],
 
     // disallow use of new operator with the require function
-    'no-new-require': 2,
+    'no-new-require': 'error',
 
     // disallow string concatenation with __dirname and __filename
-    // http://eslint.org/docs/rules/no-path-concat
-    'no-path-concat': 2,
+    // https://eslint.org/docs/rules/no-path-concat
+    'no-path-concat': 'error',
 
     // disallow use of process.env
-    'no-process-env': 0,
+    'no-process-env': 'off',
 
     // disallow process.exit()
-    'no-process-exit': 0,
+    'no-process-exit': 'off',
 
     // restrict usage of specified node modules
-    'no-restricted-modules': 0,
+    'no-restricted-modules': 'off',
 
     // disallow use of synchronous methods (off by default)
-    'no-sync': 0,
+    'no-sync': 'off',
   }
 };

packages/eslint-config-airbnb-base/rules/strict.js

@@ -1,6 +1,6 @@
 module.exports = {
   rules: {
     // babel inserts `'use strict';` for us
-    strict: [2, 'never']
+    strict: ['error', 'never']
   }
 };

packages/eslint-config-airbnb-base/rules/style.js

@@ -1,63 +1,161 @@
 module.exports = {
   rules: {
+    // enforce line breaks after opening and before closing array brackets
+    // https://eslint.org/docs/rules/array-bracket-newline
+    // TODO: enable? semver-major
+    'array-bracket-newline': ['off', 'consistent'], // object option alternative: { multiline: true, minItems: 3 }
+
+    // enforce line breaks between array elements
+    // https://eslint.org/docs/rules/array-element-newline
+    // TODO: enable? semver-major
+    'array-element-newline': ['off', { multiline: true, minItems: 3 }],
+
     // enforce spacing inside array brackets
-    'array-bracket-spacing': [2, 'never'],
+    'array-bracket-spacing': ['error', 'never'],
 
     // enforce spacing inside single-line blocks
-    // http://eslint.org/docs/rules/block-spacing
-    'block-spacing': [2, 'always'],
+    // https://eslint.org/docs/rules/block-spacing
+    'block-spacing': ['error', 'always'],
 
     // enforce one true brace style
-    'brace-style': [2, '1tbs', { allowSingleLine: true }],
+    'brace-style': ['error', '1tbs', { allowSingleLine: true }],
 
     // require camel case names
-    camelcase: [2, { properties: 'never' }],
+    camelcase: ['error', { properties: 'never', ignoreDestructuring: false }],
+
+    // enforce or disallow capitalization of the first letter of a comment
+    // https://eslint.org/docs/rules/capitalized-comments
+    'capitalized-comments': ['off', 'never', {
+      line: {
+        ignorePattern: '.*',
+        ignoreInlineComments: true,
+        ignoreConsecutiveComments: true,
+      },
+      block: {
+        ignorePattern: '.*',
+        ignoreInlineComments: true,
+        ignoreConsecutiveComments: true,
+      },
+    }],
+
+    // require trailing commas in multiline object literals
+    'comma-dangle': ['error', {
+      arrays: 'always-multiline',
+      objects: 'always-multiline',
+      imports: 'always-multiline',
+      exports: 'always-multiline',
+      functions: 'always-multiline',
+    }],
 
     // enforce spacing before and after comma
-    'comma-spacing': [2, { before: false, after: true }],
+    'comma-spacing': ['error', { before: false, after: true }],
 
     // enforce one true comma style
-    'comma-style': [2, 'last'],
+    'comma-style': ['error', 'last', {
+      exceptions: {
+        ArrayExpression: false,
+        ArrayPattern: false,
+        ArrowFunctionExpression: false,
+        CallExpression: false,
+        FunctionDeclaration: false,
+        FunctionExpression: false,
+        ImportDeclaration: false,
+        ObjectExpression: false,
+        ObjectPattern: false,
+        VariableDeclaration: false,
+        NewExpression: false,
+      }
+    }],
 
     // disallow padding inside computed properties
-    'computed-property-spacing': [2, 'never'],
+    'computed-property-spacing': ['error', 'never'],
 
     // enforces consistent naming when capturing the current execution context
-    'consistent-this': 0,
+    'consistent-this': 'off',
 
     // enforce newline at the end of file, with no multiple empty lines
-    'eol-last': 2,
+    'eol-last': ['error', 'always'],
+
+    // https://eslint.org/docs/rules/function-call-argument-newline
+    // TODO: enable, semver-minor, once eslint v6.2 is required (which is a major)
+    'function-call-argument-newline': ['off', 'consistent'],
+
+    // enforce spacing between functions and their invocations
+    // https://eslint.org/docs/rules/func-call-spacing
+    'func-call-spacing': ['error', 'never'],
+
+    // requires function names to match the name of the variable or property to which they are
+    // assigned
+    // https://eslint.org/docs/rules/func-name-matching
+    'func-name-matching': ['off', 'always', {
+      includeCommonJSModuleExports: false,
+      considerPropertyDescriptor: true,
+    }],
 
     // require function expressions to have a name
-    'func-names': 1,
+    // https://eslint.org/docs/rules/func-names
+    'func-names': 'warn',
 
     // enforces use of function declarations or expressions
-    'func-style': 0,
+    // https://eslint.org/docs/rules/func-style
+    // TODO: enable
+    'func-style': ['off', 'expression'],
+
+    // enforce consistent line breaks inside function parentheses
+    // https://eslint.org/docs/rules/function-paren-newline
+    'function-paren-newline': ['error', 'consistent'],
 
     // Blacklist certain identifiers to prevent them being used
-    // http://eslint.org/docs/rules/id-blacklist
-    'id-blacklist': 0,
+    // https://eslint.org/docs/rules/id-blacklist
+    'id-blacklist': 'off',
 
     // this option enforces minimum and maximum identifier lengths
     // (variable names, property names etc.)
-    'id-length': 0,
+    'id-length': 'off',
 
     // require identifiers to match the provided regular expression
-    'id-match': 0,
+    'id-match': 'off',
+
+    // Enforce the location of arrow function bodies with implicit returns
+    // https://eslint.org/docs/rules/implicit-arrow-linebreak
+    'implicit-arrow-linebreak': ['error', 'beside'],
 
     // this option sets a specific tab width for your code
-    // http://eslint.org/docs/rules/indent
-    indent: [2, 2, { SwitchCase: 1, VariableDeclarator: 1, outerIIFEBody: 1 }],
+    // https://eslint.org/docs/rules/indent
+    indent: ['error', 2, {
+      SwitchCase: 1,
+      VariableDeclarator: 1,
+      outerIIFEBody: 1,
+      // MemberExpression: null,
+      FunctionDeclaration: {
+        parameters: 1,
+        body: 1
+      },
+      FunctionExpression: {
+        parameters: 1,
+        body: 1
+      },
+      CallExpression: {
+        arguments: 1
+      },
+      ArrayExpression: 1,
+      ObjectExpression: 1,
+      ImportDeclaration: 1,
+      flatTernaryExpressions: false,
+      // list derived from https://github.com/benjamn/ast-types/blob/HEAD/def/jsx.js
+      ignoredNodes: ['JSXElement', 'JSXElement > *', 'JSXAttribute', 'JSXIdentifier', 'JSXNamespacedName', 'JSXMemberExpression', 'JSXSpreadAttribute', 'JSXExpressionContainer', 'JSXOpeningElement', 'JSXClosingElement', 'JSXFragment', 'JSXOpeningFragment', 'JSXClosingFragment', 'JSXText', 'JSXEmptyExpression', 'JSXSpreadChild'],
+      ignoreComments: false
+    }],
 
     // specify whether double or single quotes should be used in JSX attributes
-    // http://eslint.org/docs/rules/jsx-quotes
-    'jsx-quotes': [0, 'prefer-double'],
+    // https://eslint.org/docs/rules/jsx-quotes
+    'jsx-quotes': ['off', 'prefer-double'],
 
     // enforces spacing between keys and values in object literal properties
-    'key-spacing': [2, { beforeColon: false, afterColon: true }],
+    'key-spacing': ['error', { beforeColon: false, afterColon: true }],
 
     // require a space before & after certain keywords
-    'keyword-spacing': [2, {
+    'keyword-spacing': ['error', {
       before: true,
       after: true,
       overrides: {
@@ -67,222 +165,331 @@ module.exports = {
       }
     }],
 
+    // enforce position of line comments
+    // https://eslint.org/docs/rules/line-comment-position
+    // TODO: enable?
+    'line-comment-position': ['off', {
+      position: 'above',
+      ignorePattern: '',
+      applyDefaultPatterns: true,
+    }],
+
     // disallow mixed 'LF' and 'CRLF' as linebreaks
-    // http://eslint.org/docs/rules/linebreak-style
-    'linebreak-style': [2, 'unix'],
+    // https://eslint.org/docs/rules/linebreak-style
+    'linebreak-style': ['error', 'unix'],
+
+    // require or disallow an empty line between class members
+    // https://eslint.org/docs/rules/lines-between-class-members
+    'lines-between-class-members': ['error', 'always', { exceptAfterSingleLine: false }],
 
     // enforces empty lines around comments
-    'lines-around-comment': 0,
+    'lines-around-comment': 'off',
+
+    // require or disallow newlines around directives
+    // https://eslint.org/docs/rules/lines-around-directive
+    'lines-around-directive': ['error', {
+      before: 'always',
+      after: 'always',
+    }],
 
     // specify the maximum depth that blocks can be nested
-    'max-depth': [0, 4],
+    'max-depth': ['off', 4],
 
     // specify the maximum length of a line in your program
-    // http://eslint.org/docs/rules/max-len
-    'max-len': [2, 100, 2, {
+    // https://eslint.org/docs/rules/max-len
+    'max-len': ['error', 100, 2, {
       ignoreUrls: true,
-      ignoreComments: false
+      ignoreComments: false,
+      ignoreRegExpLiterals: true,
+      ignoreStrings: true,
+      ignoreTemplateLiterals: true,
     }],
 
     // specify the max number of lines in a file
-    // http://eslint.org/docs/rules/max-lines
-    'max-lines': [0, {
+    // https://eslint.org/docs/rules/max-lines
+    'max-lines': ['off', {
       max: 300,
       skipBlankLines: true,
       skipComments: true
     }],
 
+    // enforce a maximum function length
+    // https://eslint.org/docs/rules/max-lines-per-function
+    'max-lines-per-function': ['off', {
+      max: 50,
+      skipBlankLines: true,
+      skipComments: true,
+      IIFEs: true,
+    }],
+
     // specify the maximum depth callbacks can be nested
-    'max-nested-callbacks': 0,
+    'max-nested-callbacks': 'off',
 
     // limits the number of parameters that can be used in the function declaration.
-    'max-params': [0, 3],
+    'max-params': ['off', 3],
 
     // specify the maximum number of statement allowed in a function
-    'max-statements': [0, 10],
+    'max-statements': ['off', 10],
 
     // restrict the number of statements per line
-    // http://eslint.org/docs/rules/max-statements-per-line
-    'max-statements-per-line': [0, { max: 1 }],
+    // https://eslint.org/docs/rules/max-statements-per-line
+    'max-statements-per-line': ['off', { max: 1 }],
+
+    // enforce a particular style for multiline comments
+    // https://eslint.org/docs/rules/multiline-comment-style
+    'multiline-comment-style': ['off', 'starred-block'],
 
     // require multiline ternary
-    // http://eslint.org/docs/rules/multiline-ternary
-    'multiline-ternary': 0,
+    // https://eslint.org/docs/rules/multiline-ternary
+    // TODO: enable?
+    'multiline-ternary': ['off', 'never'],
 
     // require a capital letter for constructors
-    'new-cap': [2, { newIsCap: true }],
+    'new-cap': ['error', {
+      newIsCap: true,
+      newIsCapExceptions: [],
+      capIsNew: false,
+      capIsNewExceptions: ['Immutable.Map', 'Immutable.Set', 'Immutable.List'],
+    }],
 
     // disallow the omission of parentheses when invoking a constructor with no arguments
-    // http://eslint.org/docs/rules/new-parens
-    'new-parens': 2,
+    // https://eslint.org/docs/rules/new-parens
+    'new-parens': 'error',
 
     // allow/disallow an empty newline after var statement
-    'newline-after-var': 0,
+    'newline-after-var': 'off',
 
-    // http://eslint.org/docs/rules/newline-before-return
-    'newline-before-return': 0,
+    // https://eslint.org/docs/rules/newline-before-return
+    'newline-before-return': 'off',
 
     // enforces new line after each method call in the chain to make it
     // more readable and easy to maintain
-    // http://eslint.org/docs/rules/newline-per-chained-call
-    'newline-per-chained-call': [2, { ignoreChainWithDepth: 4 }],
+    // https://eslint.org/docs/rules/newline-per-chained-call
+    'newline-per-chained-call': ['error', { ignoreChainWithDepth: 4 }],
 
     // disallow use of the Array constructor
-    'no-array-constructor': 2,
+    'no-array-constructor': 'error',
 
     // disallow use of bitwise operators
-    // http://eslint.org/docs/rules/no-bitwise
-    // TODO: enable
-    'no-bitwise': 0,
+    // https://eslint.org/docs/rules/no-bitwise
+    'no-bitwise': 'error',
 
     // disallow use of the continue statement
-    // http://eslint.org/docs/rules/no-continue
-    'no-continue': 2,
+    // https://eslint.org/docs/rules/no-continue
+    'no-continue': 'error',
 
     // disallow comments inline after code
-    'no-inline-comments': 0,
+    'no-inline-comments': 'off',
 
     // disallow if as the only statement in an else block
-    // http://eslint.org/docs/rules/no-lonely-if
-    'no-lonely-if': 2,
+    // https://eslint.org/docs/rules/no-lonely-if
+    'no-lonely-if': 'error',
 
     // disallow un-paren'd mixes of different operators
-    // http://eslint.org/docs/rules/no-mixed-operators
-    'no-mixed-operators': [2, {
+    // https://eslint.org/docs/rules/no-mixed-operators
+    'no-mixed-operators': ['error', {
+      // the list of arthmetic groups disallows mixing `%` and `**`
+      // with other arithmetic operators.
       groups: [
-        ['+', '-', '*', '/', '%', '**'],
-        ['&', '|', '^', '~', '<<', '>>', '>>>'],
-        ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
+        ['%', '**'],
+        ['%', '+'],
+        ['%', '-'],
+        ['%', '*'],
+        ['%', '/'],
+        ['/', '*'],
+        ['&', '|', '<<', '>>', '>>>'],
+        ['==', '!=', '===', '!=='],
         ['&&', '||'],
-        ['in', 'instanceof']
       ],
       allowSamePrecedence: false
     }],
 
     // disallow mixed spaces and tabs for indentation
-    'no-mixed-spaces-and-tabs': 2,
+    'no-mixed-spaces-and-tabs': 'error',
 
-    // disallow multiple empty lines and only one newline at the end
-    'no-multiple-empty-lines': [2, { max: 2, maxEOF: 1 }],
+    // disallow use of chained assignment expressions
+    // https://eslint.org/docs/rules/no-multi-assign
+    'no-multi-assign': ['error'],
+
+    // disallow multiple empty lines, only one newline at the end, and no new lines at the beginning
+    // https://eslint.org/docs/rules/no-multiple-empty-lines
+    'no-multiple-empty-lines': ['error', { max: 1, maxBOF: 0, maxEOF: 0 }],
 
     // disallow negated conditions
-    // http://eslint.org/docs/rules/no-negated-condition
-    'no-negated-condition': 0,
+    // https://eslint.org/docs/rules/no-negated-condition
+    'no-negated-condition': 'off',
 
     // disallow nested ternary expressions
-    'no-nested-ternary': 2,
+    'no-nested-ternary': 'error',
 
     // disallow use of the Object constructor
-    'no-new-object': 2,
+    'no-new-object': 'error',
 
     // disallow use of unary operators, ++ and --
-    'no-plusplus': 0,
+    // https://eslint.org/docs/rules/no-plusplus
+    'no-plusplus': 'error',
 
     // disallow certain syntax forms
-    // http://eslint.org/docs/rules/no-restricted-syntax
+    // https://eslint.org/docs/rules/no-restricted-syntax
     'no-restricted-syntax': [
-      2,
-      'DebuggerStatement',
-      'ForInStatement',
-      'LabeledStatement',
-      'WithStatement',
+      'error',
+      {
+        selector: 'ForInStatement',
+        message: 'for..in loops iterate over the entire prototype chain, which is virtually never what you want. Use Object.{keys,values,entries}, and iterate over the resulting array.',
+      },
+      {
+        selector: 'ForOfStatement',
+        message: 'iterators/generators require regenerator-runtime, which is too heavyweight for this guide to allow them. Separately, loops should be avoided in favor of array iterations.',
+      },
+      {
+        selector: 'LabeledStatement',
+        message: 'Labels are a form of GOTO; using them makes code confusing and hard to maintain and understand.',
+      },
+      {
+        selector: 'WithStatement',
+        message: '`with` is disallowed in strict mode because it makes code impossible to predict and optimize.',
+      },
     ],
 
     // disallow space between function identifier and application
-    'no-spaced-func': 2,
+    'no-spaced-func': 'error',
 
     // disallow tab characters entirely
-    // TODO: enable
-    'no-tabs': 0,
+    'no-tabs': 'error',
 
     // disallow the use of ternary operators
-    'no-ternary': 0,
+    'no-ternary': 'off',
 
     // disallow trailing whitespace at the end of lines
-    'no-trailing-spaces': 2,
+    'no-trailing-spaces': ['error', {
+      skipBlankLines: false,
+      ignoreComments: false,
+    }],
 
     // disallow dangling underscores in identifiers
-    'no-underscore-dangle': [2, { allowAfterThis: false }],
+    // https://eslint.org/docs/rules/no-underscore-dangle
+    'no-underscore-dangle': ['error', {
+      allow: [],
+      allowAfterThis: false,
+      allowAfterSuper: false,
+      enforceInMethodNames: true,
+    }],
 
     // disallow the use of Boolean literals in conditional expressions
     // also, prefer `a || b` over `a ? a : b`
-    // http://eslint.org/docs/rules/no-unneeded-ternary
-    'no-unneeded-ternary': [2, { defaultAssignment: false }],
+    // https://eslint.org/docs/rules/no-unneeded-ternary
+    'no-unneeded-ternary': ['error', { defaultAssignment: false }],
 
     // disallow whitespace before properties
-    // http://eslint.org/docs/rules/no-whitespace-before-property
-    'no-whitespace-before-property': 2,
+    // https://eslint.org/docs/rules/no-whitespace-before-property
+    'no-whitespace-before-property': 'error',
+
+    // enforce the location of single-line statements
+    // https://eslint.org/docs/rules/nonblock-statement-body-position
+    'nonblock-statement-body-position': ['error', 'beside', { overrides: {} }],
 
     // require padding inside curly braces
-    'object-curly-spacing': [2, 'always'],
+    'object-curly-spacing': ['error', 'always'],
 
     // enforce line breaks between braces
-    // http://eslint.org/docs/rules/object-curly-newline
-    // TODO: enable once https://github.com/eslint/eslint/issues/6488 is resolved
-    'object-curly-newline': [0, {
-      ObjectExpression: { minProperties: 0, multiline: true },
-      ObjectPattern: { minProperties: 0, multiline: true }
+    // https://eslint.org/docs/rules/object-curly-newline
+    'object-curly-newline': ['error', {
+      ObjectExpression: { minProperties: 4, multiline: true, consistent: true },
+      ObjectPattern: { minProperties: 4, multiline: true, consistent: true },
+      ImportDeclaration: { minProperties: 4, multiline: true, consistent: true },
+      ExportDeclaration: { minProperties: 4, multiline: true, consistent: true },
     }],
 
     // enforce "same line" or "multiple line" on object properties.
-    // http://eslint.org/docs/rules/object-property-newline
-    'object-property-newline': [2, {
-      allowMultiplePropertiesPerLine: true,
+    // https://eslint.org/docs/rules/object-property-newline
+    'object-property-newline': ['error', {
+      allowAllPropertiesOnSameLine: true,
     }],
 
     // allow just one var statement per function
-    'one-var': [2, 'never'],
+    'one-var': ['error', 'never'],
 
     // require a newline around variable declaration
-    // http://eslint.org/docs/rules/one-var-declaration-per-line
-    'one-var-declaration-per-line': [2, 'always'],
+    // https://eslint.org/docs/rules/one-var-declaration-per-line
+    'one-var-declaration-per-line': ['error', 'always'],
 
     // require assignment operator shorthand where possible or prohibit it entirely
-    // http://eslint.org/docs/rules/operator-assignment
-    'operator-assignment': [2, 'always'],
+    // https://eslint.org/docs/rules/operator-assignment
+    'operator-assignment': ['error', 'always'],
 
-    // enforce operators to be placed before or after line breaks
-    'operator-linebreak': 0,
+    // Requires operator at the beginning of the line in multiline statements
+    // https://eslint.org/docs/rules/operator-linebreak
+    'operator-linebreak': ['error', 'before', { overrides: { '=': 'none' } }],
 
-    // enforce padding within blocks
-    'padded-blocks': [2, 'never'],
+    // disallow padding within blocks
+    'padded-blocks': ['error', {
+      blocks: 'never',
+      classes: 'never',
+      switches: 'never',
+    }, {
+      allowSingleLineBlocks: true,
+    }],
+
+    // Require or disallow padding lines between statements
+    // https://eslint.org/docs/rules/padding-line-between-statements
+    'padding-line-between-statements': 'off',
+
+    // Disallow the use of Math.pow in favor of the ** operator
+    // https://eslint.org/docs/rules/prefer-exponentiation-operator
+    // TODO: enable, semver-major when eslint 5 is dropped
+    'prefer-exponentiation-operator': 'off',
+
+    // Prefer use of an object spread over Object.assign
+    // https://eslint.org/docs/rules/prefer-object-spread
+    'prefer-object-spread': 'error',
 
     // require quotes around object literal property names
-    // http://eslint.org/docs/rules/quote-props.html
-    'quote-props': [2, 'as-needed', { keywords: false, unnecessary: true, numbers: false }],
+    // https://eslint.org/docs/rules/quote-props.html
+    'quote-props': ['error', 'as-needed', { keywords: false, unnecessary: true, numbers: false }],
 
     // specify whether double or single quotes should be used
-    quotes: [2, 'single', { avoidEscape: true }],
+    quotes: ['error', 'single', { avoidEscape: true }],
 
     // do not require jsdoc
-    // http://eslint.org/docs/rules/require-jsdoc
-    'require-jsdoc': 0,
+    // https://eslint.org/docs/rules/require-jsdoc
+    'require-jsdoc': 'off',
 
     // require or disallow use of semicolons instead of ASI
-    semi: [2, 'always'],
+    semi: ['error', 'always'],
 
     // enforce spacing before and after semicolons
-    'semi-spacing': [2, { before: false, after: true }],
+    'semi-spacing': ['error', { before: false, after: true }],
+
+    // Enforce location of semicolons
+    // https://eslint.org/docs/rules/semi-style
+    'semi-style': ['error', 'last'],
+
+    // requires object keys to be sorted
+    'sort-keys': ['off', 'asc', { caseSensitive: false, natural: true }],
 
     // sort variables within the same declaration block
-    'sort-vars': 0,
+    'sort-vars': 'off',
 
     // require or disallow space before blocks
-    'space-before-blocks': 2,
+    'space-before-blocks': 'error',
 
     // require or disallow space before function opening parenthesis
-    // http://eslint.org/docs/rules/space-before-function-paren
-    'space-before-function-paren': [2, { anonymous: 'always', named: 'never' }],
+    // https://eslint.org/docs/rules/space-before-function-paren
+    'space-before-function-paren': ['error', {
+      anonymous: 'always',
+      named: 'never',
+      asyncArrow: 'always'
+    }],
 
     // require or disallow spaces inside parentheses
-    'space-in-parens': [2, 'never'],
+    'space-in-parens': ['error', 'never'],
 
     // require spaces around operators
-    'space-infix-ops': 2,
+    'space-infix-ops': 'error',
 
     // Require or disallow spaces before/after unary operators
-    // http://eslint.org/docs/rules/space-unary-ops
-    'space-unary-ops': [2, {
+    // https://eslint.org/docs/rules/space-unary-ops
+    'space-unary-ops': ['error', {
       words: true,
       nonwords: false,
       overrides: {
@@ -290,16 +497,32 @@ module.exports = {
     }],
 
     // require or disallow a space immediately following the // or /* in a comment
-    'spaced-comment': [2, 'always', {
-      exceptions: ['-', '+'],
-      markers: ['=', '!']           // space here to support sprockets directives
+    // https://eslint.org/docs/rules/spaced-comment
+    'spaced-comment': ['error', 'always', {
+      line: {
+        exceptions: ['-', '+'],
+        markers: ['=', '!', '/'], // space here to support sprockets directives, slash for TS /// comments
+      },
+      block: {
+        exceptions: ['-', '+'],
+        markers: ['=', '!', ':', '::'], // space here to support sprockets directives and flow comment types
+        balanced: true,
+      }
     }],
 
+    // Enforce spacing around colons of switch statements
+    // https://eslint.org/docs/rules/switch-colon-spacing
+    'switch-colon-spacing': ['error', { after: true, before: false }],
+
+    // Require or disallow spacing between template tags and their literals
+    // https://eslint.org/docs/rules/template-tag-spacing
+    'template-tag-spacing': ['error', 'never'],
+
     // require or disallow the Unicode Byte Order Mark
-    // http://eslint.org/docs/rules/unicode-bom
-    'unicode-bom': [2, 'never'],
+    // https://eslint.org/docs/rules/unicode-bom
+    'unicode-bom': ['error', 'never'],
 
     // require regex literals to be wrapped in parentheses
-    'wrap-regex': 0
+    'wrap-regex': 'off'
   }
 };

packages/eslint-config-airbnb-base/rules/variables.js

@@ -1,41 +1,44 @@
+const confusingBrowserGlobals = require('confusing-browser-globals');
+
 module.exports = {
   rules: {
     // enforce or disallow variable initializations at definition
-    'init-declarations': 0,
+    'init-declarations': 'off',
 
     // disallow the catch clause parameter name being the same as a variable in the outer scope
-    'no-catch-shadow': 0,
+    'no-catch-shadow': 'off',
 
     // disallow deletion of variables
-    'no-delete-var': 2,
+    'no-delete-var': 'error',
 
     // disallow labels that share a name with a variable
-    // http://eslint.org/docs/rules/no-label-var
-    'no-label-var': 2,
+    // https://eslint.org/docs/rules/no-label-var
+    'no-label-var': 'error',
 
     // disallow specific globals
-    'no-restricted-globals': 0,
+    'no-restricted-globals': ['error', 'isFinite', 'isNaN'].concat(confusingBrowserGlobals),
 
     // disallow declaration of variables already declared in the outer scope
-    'no-shadow': 2,
+    'no-shadow': 'error',
 
     // disallow shadowing of names such as arguments
-    'no-shadow-restricted-names': 2,
+    'no-shadow-restricted-names': 'error',
 
     // disallow use of undeclared variables unless mentioned in a /*global */ block
-    'no-undef': 2,
+    'no-undef': 'error',
 
     // disallow use of undefined when initializing variables
-    'no-undef-init': 2,
+    'no-undef-init': 'error',
 
     // disallow use of undefined variable
+    // https://eslint.org/docs/rules/no-undefined
     // TODO: enable?
-    'no-undefined': 0,
+    'no-undefined': 'off',
 
     // disallow declaration of variables that are not used in the code
-    'no-unused-vars': [2, { vars: 'local', args: 'after-used' }],
+    'no-unused-vars': ['error', { vars: 'all', args: 'after-used', ignoreRestSiblings: true }],
 
     // disallow use of variables before they are defined
-    'no-use-before-define': 2
+    'no-use-before-define': ['error', { functions: true, classes: true, variables: true }],
   }
 };

packages/eslint-config-airbnb-base/test/.eslintrc

@@ -1,12 +1,8 @@
 {
   "rules": {
-    // disabled because I find it tedious to write tests while following this
-    // rule
+    // disabled because I find it tedious to write tests while following this rule
     "no-shadow": 0,
     // tests uses `t` for tape
     "id-length": [2, {"min": 2, "properties": "never", "exceptions": ["t"]}],
-    "import/no-extraneous-dependencies": [2, {
-      "devDependencies": true
-    }],
   }
 }

packages/eslint-config-airbnb-base/test/requires.js

@@ -0,0 +1,13 @@
+/* eslint strict: 0, global-require: 0 */
+
+'use strict';
+
+const test = require('tape');
+
+test('all entry points parse', (t) => {
+  t.doesNotThrow(() => require('..'), 'index does not throw');
+  t.doesNotThrow(() => require('../legacy'), 'legacy does not throw');
+  t.doesNotThrow(() => require('../whitespace'), 'whitespace does not throw');
+
+  t.end();
+});

packages/eslint-config-airbnb-base/test/test-base.js

@@ -2,28 +2,31 @@ import fs from 'fs';
 import path from 'path';
 import test from 'tape';
 
-import index from '../';
+import index from '..';
 
-const files = { index };
+const files = { ...{ index } }; // object spread is to test parsing
 
-fs.readdirSync(path.join(__dirname, '../rules')).forEach(name => {
+fs.readdirSync(path.join(__dirname, '../rules')).forEach((name) => {
+  // eslint-disable-next-line import/no-dynamic-require
   files[name] = require(`../rules/${name}`); // eslint-disable-line global-require
 });
 
-Object.keys(files).forEach(name => {
+Object.keys(files).forEach((
+  name, // trailing function comma is to test parsing
+) => {
   const config = files[name];
 
-  test(`${name}: does not reference react`, t => {
+  test(`${name}: does not reference react`, (t) => {
     t.plan(2);
 
     // scan plugins for react and fail if it is found
-    const hasReactPlugin = Object.prototype.hasOwnProperty.call(config, 'plugins') &&
-      config.plugins.indexOf('react') !== -1;
+    const hasReactPlugin = Object.prototype.hasOwnProperty.call(config, 'plugins')
+      && config.plugins.indexOf('react') !== -1;
     t.notOk(hasReactPlugin, 'there is no react plugin');
 
     // scan rules for react/ and fail if any exist
     const reactRuleIds = Object.keys(config.rules)
-      .filter(ruleId => ruleId.indexOf('react/') === 0);
+      .filter((ruleId) => ruleId.indexOf('react/') === 0);
     t.deepEquals(reactRuleIds, [], 'there are no react/ rules');
   });
 });

packages/eslint-config-airbnb-base/whitespace.js

@@ -0,0 +1,91 @@
+const assign = require('object.assign');
+const entries = require('object.entries');
+const { CLIEngine } = require('eslint');
+
+const baseConfig = require('.');
+
+const severities = ['off', 'warn', 'error'];
+
+function getSeverity(ruleConfig) {
+  if (Array.isArray(ruleConfig)) {
+    return getSeverity(ruleConfig[0]);
+  }
+  if (typeof ruleConfig === 'number') {
+    return severities[ruleConfig];
+  }
+  return ruleConfig;
+}
+
+function onlyErrorOnRules(rulesToError, config) {
+  const errorsOnly = assign({}, config);
+  const cli = new CLIEngine({ baseConfig: config, useEslintrc: false });
+  const baseRules = cli.getConfigForFile(require.resolve('./')).rules;
+
+  entries(baseRules).forEach((rule) => {
+    const ruleName = rule[0];
+    const ruleConfig = rule[1];
+    const severity = getSeverity(ruleConfig);
+
+    if (rulesToError.indexOf(ruleName) === -1 && severity === 'error') {
+      if (Array.isArray(ruleConfig)) {
+        errorsOnly.rules[ruleName] = ['warn'].concat(ruleConfig.slice(1));
+      } else if (typeof ruleConfig === 'number') {
+        errorsOnly.rules[ruleName] = 1;
+      } else {
+        errorsOnly.rules[ruleName] = 'warn';
+      }
+    }
+  });
+
+  return errorsOnly;
+}
+
+module.exports = onlyErrorOnRules([
+  'array-bracket-newline',
+  'array-bracket-spacing',
+  'array-element-newline',
+  'arrow-spacing',
+  'block-spacing',
+  'comma-spacing',
+  'computed-property-spacing',
+  'dot-location',
+  'eol-last',
+  'func-call-spacing',
+  'function-paren-newline',
+  'generator-star-spacing',
+  'implicit-arrow-linebreak',
+  'indent',
+  'key-spacing',
+  'keyword-spacing',
+  'line-comment-position',
+  'linebreak-style',
+  'multiline-ternary',
+  'newline-per-chained-call',
+  'no-irregular-whitespace',
+  'no-mixed-spaces-and-tabs',
+  'no-multi-spaces',
+  'no-regex-spaces',
+  'no-spaced-func',
+  'no-trailing-spaces',
+  'no-whitespace-before-property',
+  'nonblock-statement-body-position',
+  'object-curly-newline',
+  'object-curly-spacing',
+  'object-property-newline',
+  'one-var-declaration-per-line',
+  'operator-linebreak',
+  'padded-blocks',
+  'padding-line-between-statements',
+  'rest-spread-spacing',
+  'semi-spacing',
+  'semi-style',
+  'space-before-blocks',
+  'space-before-function-paren',
+  'space-in-parens',
+  'space-infix-ops',
+  'space-unary-ops',
+  'spaced-comment',
+  'switch-colon-spacing',
+  'template-tag-spacing',
+  'import/newline-after-import',
+], baseConfig);

packages/eslint-config-airbnb/.editorconfig

@@ -0,0 +1 @@
+../../.editorconfig

packages/eslint-config-airbnb/.eslintrc

@@ -3,6 +3,6 @@
   "rules": {
     // disable requiring trailing commas because it might be nice to revert to
     // being JSON at some point, and I don't want to make big changes now.
-    "comma-dangle": 0
-  }
+    "comma-dangle": 0,
+  },
 }

packages/eslint-config-airbnb/.npmrc

@@ -0,0 +1 @@
+../../.npmrc

packages/eslint-config-airbnb/CHANGELOG.md

@@ -1,3 +1,210 @@
+18.2.0 / 2020-06-18
+==================
+ - [new] add `eslint` `v7` (#2240)
+ - [minor] Allow using `eslint-plugin-react-hooks` v3 and v4 (#2235, #2207)
+ - [minor] Fix typo in no-multiple-empty-lines rule (#2168)
+ - [patch] set `explicitSpread` to ignore for `react/jsx-props-no-spreading` (#2237)
+ - [patch] relax `eslint-plugin-react-hooks` down to v2.3, due to a controversial change in v2.5
+ - [readme] fix typo (#2194)
+ - [deps] update `eslint-config-airbnb-base`, `eslint-plugin-jsx-a11y`, `eslint-plugin-import`, `eslint-plugin-react`, `babel-preset-airbnb`, `eslint-find-rules`, `in-publish`, `tape`, `object.entries`
+ - [tests] fix for eslint 7
+
+18.1.0 / 2020-03-12
+==================
+ - [minor] Support eslint-plugin-react-hooks@2 (#2090)
+ - [minor] add new disabled rules, update eslint
+ - [fix] `whitespace`: only set erroring rules to "warn"
+ - [patch] Remove duplicate `componentDidCatch` (#2108)
+ - [patch] Add `static-variables` to `sort-comp` rule (#2109)
+ - [readme] clarify hooks section in readme (#2074)
+ - [deps] update `eslint`, `eslint-plugin-react`, `eslint-plugin-react-hooks`, `eslint-config-airbnb-base`, `eslint-plugin-import`, `object.entries`
+ - [dev deps] update `@babel/runtime`, `babel-preset-airbnb`, `safe-publish-latest`, `tape`
+ - [tests] re-enable eslint rule `prefer-destructuring` internally (#2110)
+ - [tests] fix eslint errors from c66cfc3 (#2112)
+
+18.0.1 / 2019-08-13
+==================
+ - [patch] `react/state-in-constructor`: fix incorrect configuration
+
+18.0.0 / 2019-08-10
+==================
+ - [breaking] add eslint v6, drop eslint v4
+ - [deps] [breaking] update `eslint-config-airbnb-base`, `eslint-plugin-react`, `eslint-find-rules`, `eslint-plugin-import`
+ - [breaking] Remove rules/strict from 'extends' (#1962)
+ - [breaking] set react version to "detect"
+ - [breaking] disable `label-has-for`; enable `control-has-associated-label`
+ - [breaking] enable `react/jsx-props-no-spreading`
+ - [breaking] enable `react/jsx-fragments`
+ - [minor] enable `react/static-property-placement`
+ - [minor] enable `react/state-in-constructor`
+ - [minor] enable `react/jsx-curly-newline`
+ - [react] Add missing/unsafe lifecycle methods to react/sort-comp rule (#2043)
+ - [react] add componentDidCatch to lifecycle for react/sort-comp (#2060)
+ - [react] add `react-hooks` plugin (#2022)
+ - [dev deps] update babel-related deps to latest
+ - [tests] only run tests in non-lint per-package travis job
+ - [tests] use `eclint` instead of `editorconfig-tools`
+ - [meta] add disabled config for new react and a11y rules
+
+
+17.1.1 / 2019-07-01
+==================
+ - [patch] Turn off `react/no-multi-comp` (#2006)
+ - [patch] extend `no-underscore-dangle` to allow for redux dev tools in the main config instead (#1996)
+ - [meta] add disabled `jsx-fragments` rule
+ - [deps] update `eslint-config-airbnb-base`, `object.entries`, `eslint-plugin-import`, `eslint-plugin-react`, `eslint-plugin-jsx-a11y`, `babel-preset-airbnb`, `tape` (#2005, etc)
+ - [docs] correct JavaScript capitalization (#2046)
+ - [docs] fix docs for whitespace config (#1914, #1871)
+ - [readme] Improve eslint config setup instructions for yarn (#2001)
+
+17.1.0 / 2018-08-13
+==================
+- [new] add eslint v5 support
+- [minor] enable `label-has-associated-control` rule
+- [patch] re-enabling `jsx-one-expression-per-line` allowing single children, ignore DOM components on `jsx-no-bind`
+- [deps] update `eslint`, `eslint-config-airbnb-base`, `eslint-plugin-react`, `eslint-plugin-import`, `safe-publish-latest`, `eslint-plugin-jsx-a11y`, `eslint-find-rules`
+- [docs] fix readme typo (#1855)
+
+17.0.0 / 2018-06-21
+==================
+- [breaking] update `eslint-config-airbnb-base` to v13
+- [breaking] enable `no-useless-path-segments` (#1743)
+- [breaking] update `eslint-plugin-react` to `v7.6`; update rule configs (#1737)
+- [breaking] bump react pragma to v16; update `class-methods-use-this`'s `exceptMethods` to include `componentDidCatch` (#1704)
+- [new] Adds config entry point with only whitespace rules enabled (#1749, #1751)
+- [patch] set `forbid-foreign-prop-types` to "warn"
+- [patch] Add new methods introduced in react@16.3 (#1831)
+- [patch] `label-has-for`: Remove redundant component (#1802)
+- [patch] Add 'to' as a specialLink to the 'anchor-is-valid' a11y rule (#1648)
+- [patch] disable `no-did-mount-set-state`, since it’s necessary for server-rendering.
+- [deps] update `eslint`, `eslint-plugin-react`, `eslint-plugin-import`,
+- [dev deps] update `babel-preset-airbnb`, `tape`, `eslint-find-rules`
+- [meta] add ES2015-2018 in npm package keywords (#1587)
+- [meta] Add licenses to sub packages (#1746)
+- [docs] add `npx` shortcut (#1694)
+- [docs] Use HTTPS for links to ESLint documentation (#1628)
+
+16.1.0 / 2017-10-16
+==================
+- [deps] update `eslint-config-airbnb-base`, `eslint` to v4.9
+
+16.0.0 / 2017-10-06
+==================
+- [breaking] [deps] require `eslint` `v4`, update `eslint-config-airbnb-base`
+- [breaking] [deps] Upgrade `eslint-plugin-jsx-a11y` to `v6`; enable more a11y rules (#1482)
+- [breaking] enable/add react rules: `react/jsx-curly-brace-presence`, `react/no-typos`, `react/no-unused-state`, `react/no-redundant-should-component-update`, `react/default-props-match-prop-types`
+- [new] add `propWrapperFunctions` default settings for `eslint-plugin-react`
+- [new] Enable `react/jsx-closing-tag-location` (#1533)
+- [deps] update `eslint` v4, `eslint-plugin-react`, `tape`
+- [docs] Specify yarn-specific install instructions (#1511)
+
+15.1.0 / 2017-07-24
+==================
+- [deps] allow eslint v3 or v4 (#1447)
+- [deps] update `eslint-plugin-import`, `eslint-config-airbnb-base`
+
+15.0.2 / 2017-07-04
+==================
+- [fix] jsx should be enabled via parserOptions, not via a root ecmaFeatures
+- [deps] update `babel-preset-airbnb`, `eslint-find-rules`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y`, `eslint-plugin-react`, `tape`
+
+15.0.1 / 2017-05-15
+==================
+- [fix] set default React version to 15.0 (#1415)
+
+15.0.0 / 2017-05-14
+==================
+- [breaking] set default React version to 0.15
+- [breaking] `update eslint-plugin-jsx-a11y` to v5, enable new rules
+- [breaking] `update eslint-plugin-react` to v7, enable new rules
+- [minor] enable rules: `jsx-max-props-per-line`, `void-dom-elements-no-children`
+- [patch] Turn `ignorePureComponents` option on for react/prefer-stateless-function (#1378, #1398)
+- [deps] update `eslint`, `eslint-plugin-react`, `eslint-config-airbnb-base`
+
+14.1.0 / 2017-02-05
+==================
+- [patch] allow `eslint-plugin-jsx-a11y` to be v3 or v4. Remove `no-marquee` rule temporarily.
+- [deps] update `eslint-config-airbnb-base`, `babel-preset-airbnb`, `eslint`
+
+14.0.0 / 2017-01-08
+==================
+- [breaking] enable `react/no-array-index-key`, `react/require-default-props`
+- [breaking] [deps] update `eslint`, `eslint-plugin-import`, `eslint-plugin-react`, `eslint-config-airbnb-base`
+- [breaking] [deps] update `eslint-plugin-jsx-a11y` to v3 (#1166)
+- [docs] add note about `install-peerdeps` (#1234)
+- [docs] Updated instructions to support non-bash users (#1214)
+
+13.0.0 / 2016-11-06
+==================
+- [breaking] Enable `import/no-webpack-loader-syntax` rule (#1123)
+- [patch] `class-methods-use-this`: exempt React `getChildContext` (#1094)
+- [patch] set `react/no-unused-prop-types` skipShapeProps (#1099)
+- [deps] [breaking] update `eslint`, `eslint-config-airbnb-base`, `eslint-plugin-jsx-a11y`, `eslint-plugin-react`, `eslint-plugin-import`
+- [dev deps] update `babel-preset-airbnb`, `eslint`, `eslint-find-rules`, `tape`, `safe-publish-latest`
+- [Tests] on `node` `v7`
+- [docs] ensure latest version of config is installed (#1121)
+
+12.0.0 / 2016-09-24
+==================
+- [breaking] Enable react rules: `react/no-unescaped-entities`, `react/no-children-prop`
+- [breaking] [deps] update `eslint-config-airbnb-base`
+- [patch] disable deprecated and redundant `react/require-extension` rule (#978)
+
+11.2.0 / 2016-09-23
+==================
+- [new] set `ecmaVersion` to 2017; enable object rest/spread; update `babel-preset-airbnb`
+- [deps] update `eslint`, `eslint-config-airbnb-base`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y`, `eslint-plugin-react`, `eslint-find-rules`, `safe-publish-latest`
+
+11.1.0 / 2016-09-11
+==================
+- [deps] update `eslint-config-airbnb-base`, `eslint`
+
+11.0.0 / 2016-09-08
+==================
+- [breaking] enable `react` rules: `react/no-danger-with-children`, `react/no-unused-prop-types`, `react/style-prop-object`, `react/forbid-prop-types`, `react/jsx-no-duplicate-props`; set `react/no-danger` to “warn”
+- [breaking] enable `jsx-a11y` rules: `jsx-a11y/anchor-has-content`, `jsx-a11y/tabindex-no-positive`, `jsx-a11y/no-static-element-interactions`
+- [deps] update `eslint`, `eslint-plugin-react`, `eslint-config-airbnb-base`, `eslint-find-rules`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y`
+- [patch] set `ignoreCase` to `true` in disabled rules.
+- [docs] use “#” in example command rather than version numbers (#984)
+
+10.0.1 / 2016-08-12
+==================
+- [deps] update `eslint`, `eslint-find-rules`, `eslint-plugin-jsx-a11y`, `eslint-plugin-import`, `eslint-config-airbnb-base`
+
+10.0.0 / 2016-08-01
+==================
+- [breaking] enable jsx-a11y rules:
+ - `jsx-a11y/heading-has-content`
+ - `jsx-a11y/html-has-lang`
+ - `jsx-a11y/lang`
+ - `jsx-a11y/no-marquee`
+ - `jsx-a11y/scope`
+ - `jsx-a11y/href-no-hash`
+ - `jsx-a11y/label-has-for`
+- [breaking] enable aria rules:
+ - `jsx-a11y/aria-props`
+ - `jsx-a11y/aria-proptypes`
+ - `jsx-a11y/aria-unsupported-elements`
+ - `jsx-a11y/role-has-required-aria-props`
+ - `jsx-a11y/role-supports-aria-props`
+- [breaking] enable react rules:
+ - `react/jsx-filename-extension`
+ - `react/jsx-no-comment-textnodes`
+ - `react/jsx-no-target-blank`
+ - `react/require-extension`
+ - `react/no-render-return-value`
+ - `react/no-find-dom-node`
+ - `react/no-deprecated`
+- [deps] [breaking] update `eslint` to v3, `eslint-config-airbnb-base` to v5, `eslint-find-rules`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y` to v2, `eslint-plugin-react` to v6, `tape`. drop node < 4 support.
+- [deps] update `eslint-config-airbnb-base`, `eslint-plugin-react`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y`, `babel-tape-runner`, add `babel-preset-airbnb`. ensure react is `>=` 0.13.0
+- [patch] loosen `jsx-pascal-case` rule to allow all caps component names
+- [tests] stop testing < node 4
+- [tests] use `in-publish` because coffeescript screwed up the prepublish script for everyone
+- [tests] Only run `eslint-find-rules` on prepublish, not in tests
+- [tests] Even though the base config may not be up to date in the main package, let’s `npm link` the base package into the main one for the sake of travis-ci tests
+- [docs] update the peer dep install command to dynamically look up the right version numbers when installing peer deps
+- add `safe-publish-latest` to `prepublish`
+
 9.0.1 / 2016-05-08
 ==================
 - [patch] update `eslint-config-airbnb-base` to v3.0.1
@@ -187,36 +394,36 @@
 [pr-modular]: https://github.com/airbnb/javascript/pull/526
 [pr-legacy]: https://github.com/airbnb/javascript/pull/527
 
-[array-bracket-spacing]: http://eslint.org/docs/rules/array-bracket-spacing
-[array-callback-return]: http://eslint.org/docs/rules/array-callback-return
-[arrow-body-style]: http://eslint.org/docs/rules/arrow-body-style
-[arrow-spacing]: http://eslint.org/docs/rules/arrow-spacing
-[computed-property-spacing]: http://eslint.org/docs/rules/computed-property-spacing
-[id-length]: http://eslint.org/docs/rules/id-length
-[indent]: http://eslint.org/docs/rules/indent
-[max-len]: http://eslint.org/docs/rules/max-len
-[newline-per-chained-call]: http://eslint.org/docs/rules/newline-per-chained-call
-[no-confusing-arrow]: http://eslint.org/docs/rules/no-confusing-arrow
-[no-const-assign]: http://eslint.org/docs/rules/no-const-assign
-[no-mixed-spaces-and-tabs]: http://eslint.org/docs/rules/no-mixed-spaces-and-tabs
-[no-multiple-empty-lines]: http://eslint.org/docs/rules/no-multiple-empty-lines
-[no-new-symbol]: http://eslint.org/docs/rules/no-new-symbol
-[no-restricted-imports]: http://eslint.org/docs/rules/no-restricted-imports
-[no-self-assign]: http://eslint.org/docs/rules/no-self-assign
-[no-undef]: http://eslint.org/docs/rules/no-undef
-[no-useless-constructor]: http://eslint.org/docs/rules/no-useless-constructor
-[no-whitespace-before-property]: http://eslint.org/docs/rules/no-whitespace-before-property
-[object-curly-spacing]: http://eslint.org/docs/rules/object-curly-spacing
-[object-shorthand]: http://eslint.org/docs/rules/object-shorthand
-[one-var-declaration-per-line]: http://eslint.org/docs/rules/one-var-declaration-per-line
-[prefer-arrow-callback]: http://eslint.org/docs/rules/prefer-arrow-callback
-[prefer-rest-params]: http://eslint.org/docs/rules/prefer-rest-params
-[prefer-template]: http://eslint.org/docs/rules/prefer-template
-[quote-props]: http://eslint.org/docs/rules/quote-props
-[space-before-function-paren]: http://eslint.org/docs/rules/space-before-function-paren
-[space-before-keywords]: http://eslint.org/docs/rules/space-before-keywords
-[space-in-parens]: http://eslint.org/docs/rules/space-in-parens
-[template-curly-spacing]: http://eslint.org/docs/rules/template-curly-spacing
+[array-bracket-spacing]: https://eslint.org/docs/rules/array-bracket-spacing
+[array-callback-return]: https://eslint.org/docs/rules/array-callback-return
+[arrow-body-style]: https://eslint.org/docs/rules/arrow-body-style
+[arrow-spacing]: https://eslint.org/docs/rules/arrow-spacing
+[computed-property-spacing]: https://eslint.org/docs/rules/computed-property-spacing
+[id-length]: https://eslint.org/docs/rules/id-length
+[indent]: https://eslint.org/docs/rules/indent
+[max-len]: https://eslint.org/docs/rules/max-len
+[newline-per-chained-call]: https://eslint.org/docs/rules/newline-per-chained-call
+[no-confusing-arrow]: https://eslint.org/docs/rules/no-confusing-arrow
+[no-const-assign]: https://eslint.org/docs/rules/no-const-assign
+[no-mixed-spaces-and-tabs]: https://eslint.org/docs/rules/no-mixed-spaces-and-tabs
+[no-multiple-empty-lines]: https://eslint.org/docs/rules/no-multiple-empty-lines
+[no-new-symbol]: https://eslint.org/docs/rules/no-new-symbol
+[no-restricted-imports]: https://eslint.org/docs/rules/no-restricted-imports
+[no-self-assign]: https://eslint.org/docs/rules/no-self-assign
+[no-undef]: https://eslint.org/docs/rules/no-undef
+[no-useless-constructor]: https://eslint.org/docs/rules/no-useless-constructor
+[no-whitespace-before-property]: https://eslint.org/docs/rules/no-whitespace-before-property
+[object-curly-spacing]: https://eslint.org/docs/rules/object-curly-spacing
+[object-shorthand]: https://eslint.org/docs/rules/object-shorthand
+[one-var-declaration-per-line]: https://eslint.org/docs/rules/one-var-declaration-per-line
+[prefer-arrow-callback]: https://eslint.org/docs/rules/prefer-arrow-callback
+[prefer-rest-params]: https://eslint.org/docs/rules/prefer-rest-params
+[prefer-template]: https://eslint.org/docs/rules/prefer-template
+[quote-props]: https://eslint.org/docs/rules/quote-props
+[space-before-function-paren]: https://eslint.org/docs/rules/space-before-function-paren
+[space-before-keywords]: https://eslint.org/docs/rules/space-before-keywords
+[space-in-parens]: https://eslint.org/docs/rules/space-in-parens
+[template-curly-spacing]: https://eslint.org/docs/rules/template-curly-spacing
 
 [react/jsx-space-before-closing]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-space-before-closing.md
 [react/sort-comp]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/sort-comp.md

packages/eslint-config-airbnb/LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2012 Airbnb
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/eslint-config-airbnb/README.md

@@ -10,23 +10,60 @@ We export three ESLint configurations for your usage.
 
 ### eslint-config-airbnb
 
-Our default export contains all of our ESLint rules, including ECMAScript 6+ and React. It requires `eslint`, `eslint-plugin-import`, `eslint-plugin-react`, and `eslint-plugin-jsx-a11y`.
+Our default export contains all of our ESLint rules, including ECMAScript 6+ and React. It requires `eslint`, `eslint-plugin-import`, `eslint-plugin-react`, `eslint-plugin-react-hooks`, and `eslint-plugin-jsx-a11y`. If you don't need React, see [eslint-config-airbnb-base](https://npmjs.com/eslint-config-airbnb-base).
+
+1. Install the correct versions of each package, which are listed by the command:
+
+  ```sh
+  npm info "eslint-config-airbnb@latest" peerDependencies
+  ```
+
+  If using **npm 5+**, use this shortcut
+
+  ```sh
+  npx install-peerdeps --dev eslint-config-airbnb
+  ```
+
+  If using **yarn**, you can also use the shortcut described above if you have npm 5+ installed on your machine, as the command will detect that you are using yarn and will act accordingly.
+  Otherwise, run `npm info "eslint-config-airbnb@latest" peerDependencies` to list the peer dependencies and versions, then run `yarn add --dev <dependency>@<version>` for each listed peer dependency.
+
+  If using **npm < 5**, Linux/OSX users can run
 
-1. Ensure packages are installed with correct version numbers by running:
   ```sh
   (
     export PKG=eslint-config-airbnb;
-    npm info "$PKG" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install --save-dev "$PKG"
+    npm info "$PKG@latest" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install --save-dev "$PKG@latest"
   )
   ```
 
   Which produces and runs a command like:
 
   ```sh
-  npm install --save-dev eslint-config-airbnb eslint@^2.9.0 eslint-plugin-jsx-a11y@^1.2.0 eslint-plugin-import@^1.7.0 eslint-plugin-react@^5.0.1
+  npm install --save-dev eslint-config-airbnb eslint@^#.#.# eslint-plugin-jsx-a11y@^#.#.# eslint-plugin-import@^#.#.# eslint-plugin-react@^#.#.# eslint-plugin-react-hooks@^#.#.#
   ```
 
-2. Add `"extends": "airbnb"` to your .eslintrc
+  If using **npm < 5**, Windows users can either install all the peer dependencies manually, or use the [install-peerdeps](https://github.com/nathanhleung/install-peerdeps) cli tool.
+
+  ```sh
+  npm install -g install-peerdeps
+  install-peerdeps --dev eslint-config-airbnb
+  ```
+  The cli will produce and run a command like:
+
+  ```sh
+  npm install --save-dev eslint-config-airbnb eslint@^#.#.# eslint-plugin-jsx-a11y@^#.#.# eslint-plugin-import@^#.#.# eslint-plugin-react@^#.#.# eslint-plugin-react-hooks@^#.#.#
+  ```
+
+2. Add `"extends": "airbnb"` to your `.eslintrc`
+
+### eslint-config-airbnb/hooks
+
+This entry point enables the linting rules for React hooks (requires v16.8+). To use, add `"extends": ["airbnb", "airbnb/hooks"]` to your `.eslintrc`
+
+### eslint-config-airbnb/whitespace
+
+This entry point only errors on whitespace rules and sets all other rules to warnings. View the list of whitespace rules [here](https://github.com/airbnb/javascript/blob/master/packages/eslint-config-airbnb/whitespace.js).
+
 ### eslint-config-airbnb/base
 
 This entry point is deprecated. See [eslint-config-airbnb-base](https://npmjs.com/eslint-config-airbnb-base).
@@ -35,8 +72,8 @@ This entry point is deprecated. See [eslint-config-airbnb-base](https://npmjs.co
 
 This entry point is deprecated. See [eslint-config-airbnb-base](https://npmjs.com/eslint-config-airbnb-base).
 
-See [Airbnb's Javascript styleguide](https://github.com/airbnb/javascript) and
-the [ESlint config docs](http://eslint.org/docs/user-guide/configuring#extending-configuration-files)
+See [Airbnb's JavaScript styleguide](https://github.com/airbnb/javascript) and
+the [ESlint config docs](https://eslint.org/docs/user-guide/configuring#extending-configuration-files)
 for more information.
 
 ## Improving this config

packages/eslint-config-airbnb/hooks.js

@@ -0,0 +1,6 @@
+module.exports = {
+  extends: [
+    './rules/react-hooks.js',
+  ].map(require.resolve),
+  rules: {}
+};

packages/eslint-config-airbnb/index.js

@@ -1,7 +1,6 @@
 module.exports = {
   extends: [
     'eslint-config-airbnb-base',
-    'eslint-config-airbnb-base/rules/strict',
     './rules/react',
     './rules/react-a11y',
   ].map(require.resolve),

packages/eslint-config-airbnb/package.json

@@ -1,15 +1,20 @@
 {
   "name": "eslint-config-airbnb",
-  "version": "9.0.1",
+  "version": "18.2.0",
   "description": "Airbnb's ESLint config, following our styleguide",
   "main": "index.js",
   "scripts": {
+    "prelint": "eclint check * rules/* test/*",
     "lint": "eslint .",
+    "pretests-only": "node ./test/requires",
     "tests-only": "babel-tape-runner ./test/test-*.js",
-    "prepublish": "(in-install || eslint-find-rules --unused) && (not-in-publish || npm test)",
+    "prepublish": "(in-install || eslint-find-rules --unused) && (not-in-publish || npm test) && safe-publish-latest",
     "pretest": "npm run --silent lint",
     "test": "npm run --silent tests-only",
-    "travis": "cd ../eslint-config-airbnb-base && npm install && npm link && cd - && npm link eslint-config-airbnb-base && npm run --silent test ; npm unlink eslint-config-airbnb-base >/dev/null &"
+    "link:eslint": "cd node_modules/eslint && npm link --production && cd -",
+    "pretravis": "npm run link:eslint && cd ../eslint-config-airbnb-base && npm link eslint && npm install && npm link && cd - && npm link --no-save eslint-config-airbnb-base",
+    "travis": "npm run --silent tests-only",
+    "posttravis": "npm unlink --no-save eslint-config-airbnb-base eslint >/dev/null &"
   },
   "repository": {
     "type": "git",
@@ -21,7 +26,11 @@
     "config",
     "airbnb",
     "javascript",
-    "styleguide"
+    "styleguide",
+    "es2015",
+    "es2016",
+    "es2017",
+    "es2018"
   ],
   "author": "Jake Teton-Landis (https://twitter.com/@jitl)",
   "contributors": [
@@ -45,27 +54,34 @@
   },
   "homepage": "https://github.com/airbnb/javascript",
   "dependencies": {
-    "eslint-config-airbnb-base": "^5.0.1"
+    "eslint-config-airbnb-base": "^14.2.0",
+    "object.assign": "^4.1.0",
+    "object.entries": "^1.1.2"
   },
   "devDependencies": {
-    "babel-preset-airbnb": "^2.0.0",
-    "babel-tape-runner": "^2.0.1",
-    "eslint": "^3.2.2",
-    "eslint-find-rules": "^1.11.1",
-    "eslint-plugin-import": "^1.12.0",
-    "eslint-plugin-jsx-a11y": "^2.0.1",
-    "eslint-plugin-react": "^6.0.0",
-    "in-publish": "^2.0.0",
+    "@babel/runtime": "^7.8.7",
+    "babel-preset-airbnb": "^4.5.0",
+    "babel-tape-runner": "^3.0.0",
+    "eclint": "^2.8.1",
+    "eslint": "^5.16.0 || ^6.8.0 || ^7.2.0",
+    "eslint-find-rules": "^3.5.0",
+    "eslint-plugin-import": "^2.21.2",
+    "eslint-plugin-jsx-a11y": "^6.3.0",
+    "eslint-plugin-react": "^7.20.0",
+    "eslint-plugin-react-hooks": "^4 || ^3 || ^2.3.0 || ^1.7.0",
+    "in-publish": "^2.0.1",
     "react": ">= 0.13.0",
-    "tape": "^4.6.0"
+    "safe-publish-latest": "^1.1.4",
+    "tape": "^5.0.1"
   },
   "peerDependencies": {
-    "eslint": "^3.2.2",
-    "eslint-plugin-jsx-a11y": "^2.0.1",
-    "eslint-plugin-import": "^1.12.0",
-    "eslint-plugin-react": "^6.0.0"
+    "eslint": "^5.16.0 || ^6.8.0 || ^7.2.0",
+    "eslint-plugin-import": "^2.21.2",
+    "eslint-plugin-jsx-a11y": "^6.3.0",
+    "eslint-plugin-react": "^7.20.0",
+    "eslint-plugin-react-hooks": "^4 || ^3 || ^2.3.0 || ^1.7.0"
   },
   "engines": {
-    "node": ">= 4"
+    "node": ">= 6"
   }
 }

packages/eslint-config-airbnb/rules/react-a11y.js

@@ -3,98 +3,244 @@ module.exports = {
     'jsx-a11y',
     'react'
   ],
-  ecmaFeatures: {
-    jsx: true
+
+  parserOptions: {
+    ecmaFeatures: {
+      jsx: true,
+    },
   },
+
   rules: {
+    // Enforce that anchors have content
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/anchor-has-content.md
+    'jsx-a11y/anchor-has-content': ['error', { components: [] }],
+
     // Require ARIA roles to be valid and non-abstract
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-role.md
-    'jsx-a11y/aria-role': 2,
+    'jsx-a11y/aria-role': ['error', { ignoreNonDom: false }],
 
     // Enforce all aria-* props are valid.
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-props.md
-    'jsx-a11y/aria-props': 2,
+    'jsx-a11y/aria-props': 'error',
 
     // Enforce ARIA state and property values are valid.
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-proptypes.md
-    'jsx-a11y/aria-proptypes': 2,
+    'jsx-a11y/aria-proptypes': 'error',
 
     // Enforce that elements that do not support ARIA roles, states, and
     // properties do not have those attributes.
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-unsupported-elements.md
-    'jsx-a11y/aria-unsupported-elements': 2,
+    'jsx-a11y/aria-unsupported-elements': 'error',
 
-    // disallow href "#"
-    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/href-no-hash.md
-    'jsx-a11y/href-no-hash': [2, ['a']],
-
-    // Require <img> to have a non-empty `alt` prop, or role="presentation"
-    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/img-has-alt.md
-    'jsx-a11y/img-has-alt': 2,
+    // Enforce that all elements that require alternative text have meaningful information
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/alt-text.md
+    'jsx-a11y/alt-text': ['error', {
+      elements: ['img', 'object', 'area', 'input[type="image"]'],
+      img: [],
+      object: [],
+      area: [],
+      'input[type="image"]': [],
+    }],
 
     // Prevent img alt text from containing redundant words like "image", "picture", or "photo"
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/img-redundant-alt.md
-    'jsx-a11y/img-redundant-alt': 2,
+    'jsx-a11y/img-redundant-alt': 'error',
 
     // require that JSX labels use "htmlFor"
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/label-has-for.md
-    'jsx-a11y/label-has-for': [2, ['label']],
+    // deprecated: replaced by `label-has-associated-control` rule
+    'jsx-a11y/label-has-for': ['off', {
+      components: [],
+      required: {
+        every: ['nesting', 'id'],
+      },
+      allowChildren: false,
+    }],
+
+    // Enforce that a label tag has a text label and an associated control.
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/b800f40a2a69ad48015ae9226fbe879f946757ed/docs/rules/label-has-associated-control.md
+    'jsx-a11y/label-has-associated-control': ['error', {
+      labelComponents: [],
+      labelAttributes: [],
+      controlComponents: [],
+      assert: 'both',
+      depth: 25
+    }],
+
+    // Enforce that a control (an interactive element) has a text label.
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/control-has-associated-label.md
+    'jsx-a11y/control-has-associated-label': ['error', {
+      labelAttributes: ['label'],
+      controlComponents: [],
+      ignoreElements: [
+        'audio',
+        'canvas',
+        'embed',
+        'input',
+        'textarea',
+        'tr',
+        'video',
+      ],
+      ignoreRoles: [
+        'grid',
+        'listbox',
+        'menu',
+        'menubar',
+        'radiogroup',
+        'row',
+        'tablist',
+        'toolbar',
+        'tree',
+        'treegrid',
+      ],
+      depth: 5,
+    }],
 
     // require that mouseover/out come with focus/blur, for keyboard-only users
-    // TODO: evaluate
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/mouse-events-have-key-events.md
-    'jsx-a11y/mouse-events-have-key-events': 0,
+    'jsx-a11y/mouse-events-have-key-events': 'error',
 
     // Prevent use of `accessKey`
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-access-key.md
-    'jsx-a11y/no-access-key': 2,
+    'jsx-a11y/no-access-key': 'error',
 
     // require onBlur instead of onChange
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-onchange.md
-    'jsx-a11y/no-onchange': 0,
+    'jsx-a11y/no-onchange': 'off',
 
-    // Enforce that elements with onClick handlers must be focusable.
-    // TODO: evaluate
-    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/onclick-has-focus.md
-    'jsx-a11y/onclick-has-focus': 0,
-
-    // require things with onClick to have an aria role
-    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/onclick-has-role.md
-    'jsx-a11y/onclick-has-role': 0,
+    // Elements with an interactive role and interaction handlers must be focusable
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/interactive-supports-focus.md
+    'jsx-a11y/interactive-supports-focus': 'error',
 
     // Enforce that elements with ARIA roles must have all required attributes
     // for that role.
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/role-has-required-aria-props.md
-    'jsx-a11y/role-has-required-aria-props': 2,
+    'jsx-a11y/role-has-required-aria-props': 'error',
 
     // Enforce that elements with explicit or implicit roles defined contain
     // only aria-* properties supported by that role.
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/role-supports-aria-props.md
-    'jsx-a11y/role-supports-aria-props': 2,
+    'jsx-a11y/role-supports-aria-props': 'error',
 
     // Enforce tabIndex value is not greater than zero.
-    // TODO: evaluate
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/tabindex-no-positive.md
-    'jsx-a11y/tabindex-no-positive': 0,
+    'jsx-a11y/tabindex-no-positive': 'error',
 
     // ensure <hX> tags have content and are not aria-hidden
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/heading-has-content.md
-    'jsx-a11y/heading-has-content': [2, ['']],
+    'jsx-a11y/heading-has-content': ['error', { components: [''] }],
 
     // require HTML elements to have a "lang" prop
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/html-has-lang.md
-    'jsx-a11y/html-has-lang': 2,
+    'jsx-a11y/html-has-lang': 'error',
 
     // require HTML element's lang prop to be valid
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/lang.md
-    'jsx-a11y/lang': 2,
+    'jsx-a11y/lang': 'error',
 
-    // prevent marquee elements
-    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-marquee.md
-    'jsx-a11y/no-marquee': 2,
+    // prevent distracting elements, like <marquee> and <blink>
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-distracting-elements.md
+    'jsx-a11y/no-distracting-elements': ['error', {
+      elements: ['marquee', 'blink'],
+    }],
 
     // only allow <th> to have the "scope" attr
     // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/scope.md
-    'jsx-a11y/scope': 2,
+    'jsx-a11y/scope': 'error',
+
+    // require onClick be accompanied by onKeyUp/onKeyDown/onKeyPress
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/click-events-have-key-events.md
+    'jsx-a11y/click-events-have-key-events': 'error',
+
+    // Enforce that DOM elements without semantic behavior not have interaction handlers
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-static-element-interactions.md
+    'jsx-a11y/no-static-element-interactions': ['error', {
+      handlers: [
+        'onClick',
+        'onMouseDown',
+        'onMouseUp',
+        'onKeyPress',
+        'onKeyDown',
+        'onKeyUp',
+      ]
+    }],
+
+    // A non-interactive element does not support event handlers (mouse and key handlers)
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-noninteractive-element-interactions.md
+    'jsx-a11y/no-noninteractive-element-interactions': ['error', {
+      handlers: [
+        'onClick',
+        'onMouseDown',
+        'onMouseUp',
+        'onKeyPress',
+        'onKeyDown',
+        'onKeyUp',
+      ]
+    }],
+
+    // ensure emoji are accessible
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/accessible-emoji.md
+    'jsx-a11y/accessible-emoji': 'error',
+
+    // elements with aria-activedescendant must be tabbable
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-activedescendant-has-tabindex.md
+    'jsx-a11y/aria-activedescendant-has-tabindex': 'error',
+
+    // ensure iframe elements have a unique title
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/iframe-has-title.md
+    'jsx-a11y/iframe-has-title': 'error',
+
+    // prohibit autoFocus prop
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-autofocus.md
+    'jsx-a11y/no-autofocus': ['error', { ignoreNonDOM: true }],
+
+    // ensure HTML elements do not specify redundant ARIA roles
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-redundant-roles.md
+    'jsx-a11y/no-redundant-roles': 'error',
+
+    // media elements must have captions
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/media-has-caption.md
+    'jsx-a11y/media-has-caption': ['error', {
+      audio: [],
+      video: [],
+      track: [],
+    }],
+
+    // WAI-ARIA roles should not be used to convert an interactive element to non-interactive
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-interactive-element-to-noninteractive-role.md
+    'jsx-a11y/no-interactive-element-to-noninteractive-role': ['error', {
+      tr: ['none', 'presentation'],
+    }],
+
+    // WAI-ARIA roles should not be used to convert a non-interactive element to interactive
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-noninteractive-element-to-interactive-role.md
+    'jsx-a11y/no-noninteractive-element-to-interactive-role': ['error', {
+      ul: ['listbox', 'menu', 'menubar', 'radiogroup', 'tablist', 'tree', 'treegrid'],
+      ol: ['listbox', 'menu', 'menubar', 'radiogroup', 'tablist', 'tree', 'treegrid'],
+      li: ['menuitem', 'option', 'row', 'tab', 'treeitem'],
+      table: ['grid'],
+      td: ['gridcell'],
+    }],
+
+    // Tab key navigation should be limited to elements on the page that can be interacted with.
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-noninteractive-tabindex.md
+    'jsx-a11y/no-noninteractive-tabindex': ['error', {
+      tags: [],
+      roles: ['tabpanel'],
+    }],
+
+    // ensure <a> tags are valid
+    // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/0745af376cdc8686d85a361ce36952b1fb1ccf6e/docs/rules/anchor-is-valid.md
+    'jsx-a11y/anchor-is-valid': ['error', {
+      components: ['Link'],
+      specialLink: ['to'],
+      aspects: ['noHref', 'invalidHref', 'preferButton'],
+    }],
+
+    // Ensure the autocomplete attribute is correct and suitable for the form field it is used with
+    // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/29c68596b15c4ff0a40daae6d4a2670e36e37d35/docs/rules/autocomplete-valid.md
+    'jsx-a11y/autocomplete-valid': ['off', {
+      inputComponents: [],
+    }],
   },
 };

packages/eslint-config-airbnb/rules/react-hooks.js

@@ -0,0 +1,21 @@
+module.exports = {
+  plugins: [
+    'react-hooks',
+  ],
+
+  parserOptions: {
+    ecmaFeatures: {
+      jsx: true,
+    },
+  },
+
+  rules: {
+    // Enforce Rules of Hooks
+    // https://github.com/facebook/react/blob/c11015ff4f610ac2924d1fc6d569a17657a404fd/packages/eslint-plugin-react-hooks/src/RulesOfHooks.js
+    'react-hooks/rules-of-hooks': 'error',
+
+    // Verify the list of the dependencies for Hooks like useEffect and similar
+    // https://github.com/facebook/react/blob/1204c789776cb01fbaf3e9f032e7e2ba85a44137/packages/eslint-plugin-react-hooks/src/ExhaustiveDeps.js
+    'react-hooks/exhaustive-deps': 'error',
+  },
+};

packages/eslint-config-airbnb/rules/react.js

@@ -1,248 +1,535 @@
+const assign = require('object.assign');
+const baseStyleRules = require('eslint-config-airbnb-base/rules/style').rules;
+
+const dangleRules = baseStyleRules['no-underscore-dangle'];
+
 module.exports = {
   plugins: [
-    'react'
+    'react',
   ],
+
   parserOptions: {
     ecmaFeatures: {
       jsx: true,
     },
   },
-  ecmaFeatures: {
-    jsx: true
-  },
 
   // View link below for react rules documentation
   // https://github.com/yannickcr/eslint-plugin-react#list-of-supported-rules
   rules: {
+    'no-underscore-dangle': [dangleRules[0], assign({}, dangleRules[1], {
+      allow: dangleRules[1].allow.concat(['__REDUX_DEVTOOLS_EXTENSION_COMPOSE__']),
+    })],
+
     // Specify whether double or single quotes should be used in JSX attributes
-    // http://eslint.org/docs/rules/jsx-quotes
-    'jsx-quotes': [2, 'prefer-double'],
+    // https://eslint.org/docs/rules/jsx-quotes
+    'jsx-quotes': ['error', 'prefer-double'],
+
+    'class-methods-use-this': ['error', {
+      exceptMethods: [
+        'render',
+        'getInitialState',
+        'getDefaultProps',
+        'getChildContext',
+        'componentWillMount',
+        'UNSAFE_componentWillMount',
+        'componentDidMount',
+        'componentWillReceiveProps',
+        'UNSAFE_componentWillReceiveProps',
+        'shouldComponentUpdate',
+        'componentWillUpdate',
+        'UNSAFE_componentWillUpdate',
+        'componentDidUpdate',
+        'componentWillUnmount',
+        'componentDidCatch',
+        'getSnapshotBeforeUpdate'
+      ],
+    }],
 
     // Prevent missing displayName in a React component definition
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/display-name.md
-    'react/display-name': [0, { ignoreTranspilerName: false }],
+    'react/display-name': ['off', { ignoreTranspilerName: false }],
 
     // Forbid certain propTypes (any, array, object)
-    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-prop-types.md
-    'react/forbid-prop-types': [0, { forbid: ['any', 'array', 'object'] }],
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/forbid-prop-types.md
+    'react/forbid-prop-types': ['error', {
+      forbid: ['any', 'array', 'object'],
+      checkContextTypes: true,
+      checkChildContextTypes: true,
+    }],
+
+    // Forbid certain props on DOM Nodes
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/forbid-dom-props.md
+    'react/forbid-dom-props': ['off', { forbid: [] }],
 
     // Enforce boolean attributes notation in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-boolean-value.md
-    'react/jsx-boolean-value': [2, 'never'],
+    'react/jsx-boolean-value': ['error', 'never', { always: [] }],
 
     // Validate closing bracket location in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-bracket-location.md
-    'react/jsx-closing-bracket-location': [2, 'line-aligned'],
+    'react/jsx-closing-bracket-location': ['error', 'line-aligned'],
+
+    // Validate closing tag location in JSX
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-tag-location.md
+    'react/jsx-closing-tag-location': 'error',
 
     // Enforce or disallow spaces inside of curly braces in JSX attributes
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-curly-spacing.md
-    'react/jsx-curly-spacing': [2, 'never', { allowMultiline: true }],
+    'react/jsx-curly-spacing': ['error', 'never', { allowMultiline: true }],
 
     // Enforce event handler naming conventions in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-handler-names.md
-    'react/jsx-handler-names': [0, {
+    'react/jsx-handler-names': ['off', {
       eventHandlerPrefix: 'handle',
       eventHandlerPropPrefix: 'on',
     }],
 
     // Validate props indentation in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-indent-props.md
-    'react/jsx-indent-props': [2, 2],
+    'react/jsx-indent-props': ['error', 2],
 
     // Validate JSX has key prop when in array or iterator
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-key.md
-    'react/jsx-key': 0,
+    'react/jsx-key': 'off',
 
     // Limit maximum of props on a single line in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-max-props-per-line.md
-    'react/jsx-max-props-per-line': [0, { maximum: 1 }],
+    'react/jsx-max-props-per-line': ['error', { maximum: 1, when: 'multiline' }],
 
     // Prevent usage of .bind() in JSX props
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-bind.md
-    'react/jsx-no-bind': [2, {
+    'react/jsx-no-bind': ['error', {
       ignoreRefs: true,
       allowArrowFunctions: true,
+      allowFunctions: false,
       allowBind: false,
+      ignoreDOMComponents: true,
     }],
 
     // Prevent duplicate props in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-duplicate-props.md
-    'react/jsx-no-duplicate-props': [0, { ignoreCase: false }],
+    'react/jsx-no-duplicate-props': ['error', { ignoreCase: true }],
 
     // Prevent usage of unwrapped JSX strings
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-literals.md
-    'react/jsx-no-literals': 0,
+    'react/jsx-no-literals': ['off', { noStrings: true }],
 
     // Disallow undeclared variables in JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-undef.md
-    'react/jsx-no-undef': 2,
+    'react/jsx-no-undef': 'error',
 
     // Enforce PascalCase for user-defined JSX components
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-pascal-case.md
-    'react/jsx-pascal-case': [2, {
+    'react/jsx-pascal-case': ['error', {
       allowAllCaps: true,
       ignore: [],
     }],
 
     // Enforce propTypes declarations alphabetical sorting
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/sort-prop-types.md
-    'react/sort-prop-types': [0, {
-      ignoreCase: false,
+    'react/sort-prop-types': ['off', {
+      ignoreCase: true,
       callbacksLast: false,
       requiredFirst: false,
+      sortShapeProp: true,
     }],
 
     // Deprecated in favor of react/jsx-sort-props
-    'react/jsx-sort-prop-types': 0,
+    'react/jsx-sort-prop-types': 'off',
 
     // Enforce props alphabetical sorting
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-sort-props.md
-    'react/jsx-sort-props': [0, {
-      ignoreCase: false,
+    'react/jsx-sort-props': ['off', {
+      ignoreCase: true,
       callbacksLast: false,
       shorthandFirst: false,
       shorthandLast: false,
+      noSortAlphabetically: false,
+      reservedFirst: true,
+    }],
+
+    // Enforce defaultProps declarations alphabetical sorting
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/jsx-sort-default-props.md
+    'react/jsx-sort-default-props': ['off', {
+      ignoreCase: true,
     }],
 
     // Prevent React to be incorrectly marked as unused
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-uses-react.md
-    'react/jsx-uses-react': [2],
+    'react/jsx-uses-react': ['error'],
 
     // Prevent variables used in JSX to be incorrectly marked as unused
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-uses-vars.md
-    'react/jsx-uses-vars': 2,
+    'react/jsx-uses-vars': 'error',
 
     // Prevent usage of dangerous JSX properties
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-danger.md
-    'react/no-danger': 0,
+    'react/no-danger': 'warn',
 
     // Prevent usage of deprecated methods
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-deprecated.md
-    'react/no-deprecated': [2],
+    'react/no-deprecated': ['error'],
 
     // Prevent usage of setState in componentDidMount
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-did-mount-set-state.md
-    'react/no-did-mount-set-state': [2],
+    // this is necessary for server-rendering
+    'react/no-did-mount-set-state': 'off',
 
     // Prevent usage of setState in componentDidUpdate
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-did-update-set-state.md
-    'react/no-did-update-set-state': [2],
+    'react/no-did-update-set-state': 'error',
+
+    // Prevent usage of setState in componentWillUpdate
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-will-update-set-state.md
+    'react/no-will-update-set-state': 'error',
 
     // Prevent direct mutation of this.state
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-direct-mutation-state.md
-    'react/no-direct-mutation-state': 0,
+    'react/no-direct-mutation-state': 'off',
 
     // Prevent usage of isMounted
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-is-mounted.md
-    'react/no-is-mounted': 2,
+    'react/no-is-mounted': 'error',
 
     // Prevent multiple component definition per file
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-multi-comp.md
-    'react/no-multi-comp': [2, { ignoreStateless: true }],
+    'react/no-multi-comp': 'off',
 
     // Prevent usage of setState
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-set-state.md
-    'react/no-set-state': 0,
+    'react/no-set-state': 'off',
 
     // Prevent using string references
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-string-refs.md
-    'react/no-string-refs': 2,
+    'react/no-string-refs': 'error',
 
     // Prevent usage of unknown DOM property
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-unknown-property.md
-    'react/no-unknown-property': 2,
+    'react/no-unknown-property': 'error',
 
     // Require ES6 class declarations over React.createClass
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-es6-class.md
-    'react/prefer-es6-class': [2, 'always'],
+    'react/prefer-es6-class': ['error', 'always'],
 
     // Require stateless functions when not using lifecycle methods, setState or ref
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-stateless-function.md
-    'react/prefer-stateless-function': 2,
+    'react/prefer-stateless-function': ['error', { ignorePureComponents: true }],
 
     // Prevent missing props validation in a React component definition
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prop-types.md
-    'react/prop-types': [2, { ignore: [], customValidators: [] }],
+    'react/prop-types': ['error', {
+      ignore: [],
+      customValidators: [],
+      skipUndeclared: false
+    }],
 
     // Prevent missing React when using JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/react-in-jsx-scope.md
-    'react/react-in-jsx-scope': 2,
-
-    // Restrict file extensions that may be required
-    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/require-extension.md
-    'react/require-extension': [2, { extensions: ['.jsx', '.js'] }],
+    'react/react-in-jsx-scope': 'error',
 
     // Require render() methods to return something
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/require-render-return.md
-    'react/require-render-return': 2,
+    'react/require-render-return': 'error',
 
     // Prevent extra closing tags for components without children
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/self-closing-comp.md
-    'react/self-closing-comp': 2,
-
-    // Enforce spaces before the closing bracket of self-closing JSX elements
-    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-space-before-closing.md
-    'react/jsx-space-before-closing': [2, 'always'],
+    'react/self-closing-comp': 'error',
 
     // Enforce component methods order
-    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/sort-comp.md
-    'react/sort-comp': [2, {
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/sort-comp.md
+    'react/sort-comp': ['error', {
       order: [
+        'static-variables',
         'static-methods',
+        'instance-variables',
         'lifecycle',
         '/^on.+$/',
+        'getters',
+        'setters',
         '/^(get|set)(?!(InitialState$|DefaultProps$|ChildContext$)).+$/',
+        'instance-methods',
         'everything-else',
-        '/^render.+$/',
-        'render'
+        'rendering',
       ],
+      groups: {
+        lifecycle: [
+          'displayName',
+          'propTypes',
+          'contextTypes',
+          'childContextTypes',
+          'mixins',
+          'statics',
+          'defaultProps',
+          'constructor',
+          'getDefaultProps',
+          'getInitialState',
+          'state',
+          'getChildContext',
+          'getDerivedStateFromProps',
+          'componentWillMount',
+          'UNSAFE_componentWillMount',
+          'componentDidMount',
+          'componentWillReceiveProps',
+          'UNSAFE_componentWillReceiveProps',
+          'shouldComponentUpdate',
+          'componentWillUpdate',
+          'UNSAFE_componentWillUpdate',
+          'getSnapshotBeforeUpdate',
+          'componentDidUpdate',
+          'componentDidCatch',
+          'componentWillUnmount'
+        ],
+        rendering: [
+          '/^render.+$/',
+          'render'
+        ],
+      },
     }],
 
     // Prevent missing parentheses around multilines JSX
-    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-wrap-multilines.md
-    'react/jsx-wrap-multilines': [2, {
-      declaration: true,
-      assignment: true,
-      return: true
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/jsx-wrap-multilines.md
+    'react/jsx-wrap-multilines': ['error', {
+      declaration: 'parens-new-line',
+      assignment: 'parens-new-line',
+      return: 'parens-new-line',
+      arrow: 'parens-new-line',
+      condition: 'parens-new-line',
+      logical: 'parens-new-line',
+      prop: 'parens-new-line',
     }],
-    'react/wrap-multilines': 0, // deprecated version
 
     // Require that the first prop in a JSX element be on a new line when the element is multiline
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-first-prop-new-line.md
-    'react/jsx-first-prop-new-line': [2, 'multiline'],
+    'react/jsx-first-prop-new-line': ['error', 'multiline-multiprop'],
 
     // Enforce spacing around jsx equals signs
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-equals-spacing.md
-    'react/jsx-equals-spacing': [2, 'never'],
+    'react/jsx-equals-spacing': ['error', 'never'],
 
     // Enforce JSX indentation
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-indent.md
-    'react/jsx-indent': [2, 2],
+    'react/jsx-indent': ['error', 2],
 
     // Disallow target="_blank" on links
-    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-target-blank.md
-    'react/jsx-no-target-blank': 2,
+    // https://github.com/yannickcr/eslint-plugin-react/blob/ac102885765be5ff37847a871f239c6703e1c7cc/docs/rules/jsx-no-target-blank.md
+    'react/jsx-no-target-blank': ['error', { enforceDynamicLinks: 'always' }],
 
     // only .jsx files may have JSX
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-filename-extension.md
-    'react/jsx-filename-extension': [2, { extensions: ['.jsx'] }],
+    'react/jsx-filename-extension': ['error', { extensions: ['.jsx'] }],
 
     // prevent accidental JS comments from being injected into JSX as text
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-comment-textnodes.md
-    'react/jsx-no-comment-textnodes': 2,
-    'react/no-comment-textnodes': 0, // deprecated version
+    'react/jsx-no-comment-textnodes': 'error',
 
     // disallow using React.render/ReactDOM.render's return value
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-render-return-value.md
-    'react/no-render-return-value': 2,
+    'react/no-render-return-value': 'error',
 
     // require a shouldComponentUpdate method, or PureRenderMixin
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/require-optimization.md
-    'react/require-optimization': [0, { allowDecorators: [] }],
+    'react/require-optimization': ['off', { allowDecorators: [] }],
 
     // warn against using findDOMNode()
     // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-find-dom-node.md
-    'react/no-find-dom-node': 2,
+    'react/no-find-dom-node': 'error',
+
+    // Forbid certain props on Components
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-component-props.md
+    'react/forbid-component-props': ['off', { forbid: [] }],
+
+    // Forbid certain elements
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-elements.md
+    'react/forbid-elements': ['off', { forbid: [], }],
+
+    // Prevent problem with children and props.dangerouslySetInnerHTML
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-danger-with-children.md
+    'react/no-danger-with-children': 'error',
+
+    // Prevent unused propType definitions
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-unused-prop-types.md
+    'react/no-unused-prop-types': ['error', {
+      customValidators: [
+      ],
+      skipShapeProps: true,
+    }],
+
+    // Require style prop value be an object or var
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/style-prop-object.md
+    'react/style-prop-object': 'error',
+
+    // Prevent invalid characters from appearing in markup
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-unescaped-entities.md
+    'react/no-unescaped-entities': 'error',
+
+    // Prevent passing of children as props
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-children-prop.md
+    'react/no-children-prop': 'error',
+
+    // Validate whitespace in and around the JSX opening and closing brackets
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/jsx-tag-spacing.md
+    'react/jsx-tag-spacing': ['error', {
+      closingSlash: 'never',
+      beforeSelfClosing: 'always',
+      afterOpening: 'never',
+      beforeClosing: 'never',
+    }],
+
+    // Enforce spaces before the closing bracket of self-closing JSX elements
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-space-before-closing.md
+    // Deprecated in favor of jsx-tag-spacing
+    'react/jsx-space-before-closing': ['off', 'always'],
+
+    // Prevent usage of Array index in keys
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-array-index-key.md
+    'react/no-array-index-key': 'error',
+
+    // Enforce a defaultProps definition for every prop that is not a required prop
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/require-default-props.md
+    'react/require-default-props': ['error', {
+      forbidDefaultForRequired: true,
+    }],
+
+    // Forbids using non-exported propTypes
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-foreign-prop-types.md
+    // this is intentionally set to "warn". it would be "error",
+    // but it's only critical if you're stripping propTypes in production.
+    'react/forbid-foreign-prop-types': ['warn', { allowInPropTypes: true }],
+
+    // Prevent void DOM elements from receiving children
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/void-dom-elements-no-children.md
+    'react/void-dom-elements-no-children': 'error',
+
+    // Enforce all defaultProps have a corresponding non-required PropType
+    // https://github.com/yannickcr/eslint-plugin-react/blob/9e13ae2c51e44872b45cc15bf1ac3a72105bdd0e/docs/rules/default-props-match-prop-types.md
+    'react/default-props-match-prop-types': ['error', { allowRequiredDefaults: false }],
+
+    // Prevent usage of shouldComponentUpdate when extending React.PureComponent
+    // https://github.com/yannickcr/eslint-plugin-react/blob/9e13ae2c51e44872b45cc15bf1ac3a72105bdd0e/docs/rules/no-redundant-should-component-update.md
+    'react/no-redundant-should-component-update': 'error',
+
+    // Prevent unused state values
+    // https://github.com/yannickcr/eslint-plugin-react/pull/1103/
+    'react/no-unused-state': 'error',
+
+    // Enforces consistent naming for boolean props
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/boolean-prop-naming.md
+    'react/boolean-prop-naming': ['off', {
+      propTypeNames: ['bool', 'mutuallyExclusiveTrueProps'],
+      rule: '^(is|has)[A-Z]([A-Za-z0-9]?)+',
+      message: '',
+    }],
+
+    // Prevents common casing typos
+    // https://github.com/yannickcr/eslint-plugin-react/blob/73abadb697034b5ccb514d79fb4689836fe61f91/docs/rules/no-typos.md
+    'react/no-typos': 'error',
+
+    // Enforce curly braces or disallow unnecessary curly braces in JSX props and/or children
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-curly-brace-presence.md
+    'react/jsx-curly-brace-presence': ['error', { props: 'never', children: 'never' }],
+
+    // One JSX Element Per Line
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/jsx-one-expression-per-line.md
+    'react/jsx-one-expression-per-line': ['error', { allow: 'single-child' }],
+
+    // Enforce consistent usage of destructuring assignment of props, state, and context
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/destructuring-assignment.md
+    'react/destructuring-assignment': ['error', 'always'],
+
+    // Prevent using this.state within a this.setState
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/no-access-state-in-setstate.md
+    'react/no-access-state-in-setstate': 'error',
+
+    // Prevent usage of button elements without an explicit type attribute
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/button-has-type.md
+    'react/button-has-type': ['error', {
+      button: true,
+      submit: true,
+      reset: false,
+    }],
+
+    // Ensures inline tags are not rendered without spaces between them
+    'react/jsx-child-element-spacing': 'off',
+
+    // Prevent this from being used in stateless functional components
+    // https://github.com/yannickcr/eslint-plugin-react/blob/843d71a432baf0f01f598d7cf1eea75ad6896e4b/docs/rules/no-this-in-sfc.md
+    'react/no-this-in-sfc': 'error',
+
+    // Validate JSX maximum depth
+    // https://github.com/yannickcr/eslint-plugin-react/blob/abe8381c0d6748047224c430ce47f02e40160ed0/docs/rules/jsx-max-depth.md
+    'react/jsx-max-depth': 'off',
+
+    // Disallow multiple spaces between inline JSX props
+    // https://github.com/yannickcr/eslint-plugin-react/blob/ac102885765be5ff37847a871f239c6703e1c7cc/docs/rules/jsx-props-no-multi-spaces.md
+    'react/jsx-props-no-multi-spaces': 'error',
+
+    // Prevent usage of UNSAFE_ methods
+    // https://github.com/yannickcr/eslint-plugin-react/blob/157cc932be2cfaa56b3f5b45df6f6d4322a2f660/docs/rules/no-unsafe.md
+    'react/no-unsafe': 'off',
+
+    // Enforce shorthand or standard form for React fragments
+    // https://github.com/yannickcr/eslint-plugin-react/blob/bc976b837abeab1dffd90ac6168b746a83fc83cc/docs/rules/jsx-fragments.md
+    'react/jsx-fragments': ['error', 'syntax'],
+
+    // Enforce linebreaks in curly braces in JSX attributes and expressions.
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-curly-newline.md
+    'react/jsx-curly-newline': ['error', {
+      multiline: 'consistent',
+      singleline: 'consistent',
+    }],
+
+    // Enforce state initialization style
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/state-in-constructor.md
+    // TODO: set to "never" once babel-preset-airbnb supports public class fields
+    'react/state-in-constructor': ['error', 'always'],
+
+    // Enforces where React component static properties should be positioned
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/static-property-placement.md
+    // TODO: set to "static public field" once babel-preset-airbnb supports public class fields
+    'react/static-property-placement': ['error', 'property assignment'],
+
+    // Disallow JSX props spreading
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-props-no-spreading.md
+    'react/jsx-props-no-spreading': ['error', {
+      html: 'enforce',
+      custom: 'enforce',
+      explicitSpread: 'ignore',
+      exceptions: [],
+    }],
+
+    // Enforce that props are read-only
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-read-only-props.md
+    'react/prefer-read-only-props': 'off',
+
+    // Prevent usage of `javascript:` URLs
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-script-url.md
+    // TODO: enable, semver-major
+    'react/jsx-no-script-url': ['off', [
+      {
+        name: 'Link',
+        props: ['to'],
+      },
+    ]],
+
+    // Disallow unnecessary fragments
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-useless-fragment.md
+    // TODO: enable, semver-major
+    'react/jsx-no-useless-fragment': 'off',
+
+    // Prevent adjacent inline elements not separated by whitespace
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-adjacent-inline-elements.md
+    // TODO: enable? semver-major
+    'react/no-adjacent-inline-elements': 'off',
+
+    // Enforce a specific function type for function components
+    // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/function-component-definition.md
+    // TODO: enable! semver-minor, but do it in a major to be safe
+    // TODO: investigate if setting namedComponents to expression vs declaration is problematic
+    'react/function-component-definition': ['off', {
+      namedComponents: 'function-expression',
+      unnamedComponents: 'function-expression',
+    }],
   },
 
   settings: {
@@ -253,7 +540,12 @@ module.exports = {
     },
     react: {
       pragma: 'React',
-      version: '0.14'
+      version: 'detect',
     },
+    propWrapperFunctions: [
+      'forbidExtraProps', // https://www.npmjs.com/package/airbnb-prop-types
+      'exact', // https://www.npmjs.com/package/prop-types-exact
+      'Object.freeze', // https://tc39.github.io/ecma262/#sec-object.freeze
+    ],
   }
 };

packages/eslint-config-airbnb/test/.eslintrc

@@ -1,13 +1,9 @@
 {
   "rules": {
-    // disabled because I find it tedious to write tests while following this
-    // rule
+    // disabled because I find it tedious to write tests while following this rule
     "no-shadow": 0,
 
     // tests uses `t` for tape
-    "id-length": [2, {"min": 2, "properties": "never", "exceptions": ["t"]}],
-
-    // tests can import things in devDependencies
-    "import/no-extraneous-dependencies": [2, {"devDependencies": true}]
+    "id-length": [2, {"min": 2, "properties": "never", "exceptions": ["t"]}]
   }
 }

packages/eslint-config-airbnb/test/requires.js

@@ -0,0 +1,15 @@
+/* eslint strict: 0, global-require: 0 */
+
+'use strict';
+
+const test = require('tape');
+
+test('all entry points parse', (t) => {
+  t.doesNotThrow(() => require('..'), 'index does not throw');
+  t.doesNotThrow(() => require('../base'), 'base does not throw');
+  t.doesNotThrow(() => require('../legacy'), 'legacy does not throw');
+  t.doesNotThrow(() => require('../whitespace'), 'whitespace does not throw');
+  t.doesNotThrow(() => require('../hooks'), 'hooks does not throw');
+
+  t.end();
+});

packages/eslint-config-airbnb/test/test-base.js

@@ -6,28 +6,29 @@ const base = require('../base');
 
 const files = { base };
 
-fs.readdirSync(path.join(__dirname, '../rules')).forEach(name => {
+fs.readdirSync(path.join(__dirname, '../rules')).forEach((name) => {
   if (name === 'react.js' || name === 'react-a11y.js') {
     return;
   }
 
+  // eslint-disable-next-line import/no-dynamic-require
   files[name] = require(`../rules/${name}`); // eslint-disable-line global-require
 });
 
-Object.keys(files).forEach(name => {
+Object.keys(files).forEach((name) => {
   const config = files[name];
 
-  test(`${name}: does not reference react`, t => {
+  test(`${name}: does not reference react`, (t) => {
     t.plan(2);
 
     // scan plugins for react and fail if it is found
-    const hasReactPlugin = Object.prototype.hasOwnProperty.call(config, 'plugins') &&
-      config.plugins.indexOf('react') !== -1;
+    const hasReactPlugin = Object.prototype.hasOwnProperty.call(config, 'plugins')
+      && config.plugins.indexOf('react') !== -1;
     t.notOk(hasReactPlugin, 'there is no react plugin');
 
     // scan rules for react/ and fail if any exist
     const reactRuleIds = Object.keys(config.rules)
-      .filter(ruleId => ruleId.indexOf('react/') === 0);
+      .filter((ruleId) => ruleId.indexOf('react/') === 0);
     t.deepEquals(reactRuleIds, [], 'there are no react/ rules');
   });
 });

packages/eslint-config-airbnb/test/test-react-order.js

@@ -1,34 +1,35 @@
 import test from 'tape';
-import { CLIEngine } from 'eslint';
-import eslintrc from '../';
+import { CLIEngine, ESLint } from 'eslint';
+import eslintrc from '..';
 import reactRules from '../rules/react';
 import reactA11yRules from '../rules/react-a11y';
 
-const cli = new CLIEngine({
+const cli = new (CLIEngine || ESLint)({
   useEslintrc: false,
   baseConfig: eslintrc,
 
   rules: {
     // It is okay to import devDependencies in tests.
     'import/no-extraneous-dependencies': [2, { devDependencies: true }],
+    // this doesn't matter for tests
+    'lines-between-class-members': 0,
   },
 });
 
 function lint(text) {
-  // @see http://eslint.org/docs/developer-guide/nodejs-api.html#executeonfiles
-  // @see http://eslint.org/docs/developer-guide/nodejs-api.html#executeontext
-  const linter = cli.executeOnText(text);
+  // @see https://eslint.org/docs/developer-guide/nodejs-api.html#executeonfiles
+  // @see https://eslint.org/docs/developer-guide/nodejs-api.html#executeontext
+  const linter = CLIEngine ? cli.executeOnText(text) : cli.lintText(text);
   return linter.results[0];
 }
 
 function wrapComponent(body) {
-  return `
+  return `\
 import React from 'react';
 
 export default class MyComponent extends React.Component {
-/* eslint no-empty-function: 0 */
-${body}
-}
+/* eslint no-empty-function: 0, class-methods-use-this: 0 */
+${body}}
 `;
 }
 
@@ -42,7 +43,6 @@ test('validate react prop order', (t) => {
   t.test('passes a good component', (t) => {
     t.plan(3);
     const result = lint(wrapComponent(`
-  componentWillMount() {}
   componentDidMount() {}
   setFoo() {}
   getFoo() {}
@@ -53,15 +53,14 @@ test('validate react prop order', (t) => {
 `));
 
     t.notOk(result.warningCount, 'no warnings');
-    t.notOk(result.errorCount, 'no errors');
     t.deepEquals(result.messages, [], 'no messages in results');
+    t.notOk(result.errorCount, 'no errors');
   });
 
-  t.test('order: when random method is first', t => {
+  t.test('order: when random method is first', (t) => {
     t.plan(2);
     const result = lint(wrapComponent(`
   someMethod() {}
-  componentWillMount() {}
   componentDidMount() {}
   setFoo() {}
   getFoo() {}
@@ -71,13 +70,12 @@ test('validate react prop order', (t) => {
 `));
 
     t.ok(result.errorCount, 'fails');
-    t.equal(result.messages[0].ruleId, 'react/sort-comp', 'fails due to sort');
+    t.deepEqual(result.messages.map((msg) => msg.ruleId), ['react/sort-comp'], 'fails due to sort');
   });
 
-  t.test('order: when random method after lifecycle methods', t => {
+  t.test('order: when random method after lifecycle methods', (t) => {
     t.plan(2);
     const result = lint(wrapComponent(`
-  componentWillMount() {}
   componentDidMount() {}
   someMethod() {}
   setFoo() {}
@@ -88,6 +86,6 @@ test('validate react prop order', (t) => {
 `));
 
     t.ok(result.errorCount, 'fails');
-    t.equal(result.messages[0].ruleId, 'react/sort-comp', 'fails due to sort');
+    t.deepEqual(result.messages.map((msg) => msg.ruleId), ['react/sort-comp'], 'fails due to sort');
   });
 });

packages/eslint-config-airbnb/whitespace.js

@@ -0,0 +1,105 @@
+const assign = require('object.assign');
+const entries = require('object.entries');
+const { CLIEngine } = require('eslint');
+
+const baseConfig = require('.');
+
+const severities = ['off', 'warn', 'error'];
+
+function getSeverity(ruleConfig) {
+  if (Array.isArray(ruleConfig)) {
+    return getSeverity(ruleConfig[0]);
+  }
+  if (typeof ruleConfig === 'number') {
+    return severities[ruleConfig];
+  }
+  return ruleConfig;
+}
+
+function onlyErrorOnRules(rulesToError, config) {
+  const errorsOnly = assign({}, config);
+  const cli = new CLIEngine({ baseConfig: config, useEslintrc: false });
+  const baseRules = cli.getConfigForFile(require.resolve('./')).rules;
+
+  entries(baseRules).forEach((rule) => {
+    const ruleName = rule[0];
+    const ruleConfig = rule[1];
+    const severity = getSeverity(ruleConfig);
+
+    if (rulesToError.indexOf(ruleName) === -1 && severity === 'error') {
+      if (Array.isArray(ruleConfig)) {
+        errorsOnly.rules[ruleName] = ['warn'].concat(ruleConfig.slice(1));
+      } else if (typeof ruleConfig === 'number') {
+        errorsOnly.rules[ruleName] = 1;
+      } else {
+        errorsOnly.rules[ruleName] = 'warn';
+      }
+    }
+  });
+
+  return errorsOnly;
+}
+
+module.exports = onlyErrorOnRules([
+  'array-bracket-newline',
+  'array-bracket-spacing',
+  'array-element-newline',
+  'arrow-spacing',
+  'block-spacing',
+  'comma-spacing',
+  'computed-property-spacing',
+  'dot-location',
+  'eol-last',
+  'func-call-spacing',
+  'function-paren-newline',
+  'generator-star-spacing',
+  'implicit-arrow-linebreak',
+  'indent',
+  'key-spacing',
+  'keyword-spacing',
+  'line-comment-position',
+  'linebreak-style',
+  'multiline-ternary',
+  'newline-per-chained-call',
+  'no-irregular-whitespace',
+  'no-mixed-spaces-and-tabs',
+  'no-multi-spaces',
+  'no-regex-spaces',
+  'no-spaced-func',
+  'no-trailing-spaces',
+  'no-whitespace-before-property',
+  'nonblock-statement-body-position',
+  'object-curly-newline',
+  'object-curly-spacing',
+  'object-property-newline',
+  'one-var-declaration-per-line',
+  'operator-linebreak',
+  'padded-blocks',
+  'padding-line-between-statements',
+  'rest-spread-spacing',
+  'semi-spacing',
+  'semi-style',
+  'space-before-blocks',
+  'space-before-function-paren',
+  'space-in-parens',
+  'space-infix-ops',
+  'space-unary-ops',
+  'spaced-comment',
+  'switch-colon-spacing',
+  'template-tag-spacing',
+  'import/newline-after-import',
+  // eslint-plugin-react rules
+  'react/jsx-child-element-spacing',
+  'react/jsx-closing-bracket-location',
+  'react/jsx-closing-tag-location',
+  'react/jsx-curly-spacing',
+  'react/jsx-equals-spacing',
+  'react/jsx-first-prop-newline',
+  'react/jsx-indent',
+  'react/jsx-indent-props',
+  'react/jsx-max-props-per-line',
+  'react/jsx-one-expression-per-line',
+  'react/jsx-space-before-closing',
+  'react/jsx-tag-spacing',
+  'react/jsx-wrap-multilines',
+], baseConfig);

react/README.md

@@ -2,10 +2,13 @@
 
 *A mostly reasonable approach to React and JSX*
 
+This style guide is mostly based on the standards that are currently prevalent in JavaScript, although some conventions (i.e async/await or static class fields) may still be included or prohibited on a case-by-case basis. Currently, anything prior to stage 3 is not included nor recommended in this guide.
+
 ## Table of Contents
 
   1. [Basic Rules](#basic-rules)
   1. [Class vs `React.createClass` vs stateless](#class-vs-reactcreateclass-vs-stateless)
+  1. [Mixins](#mixins)
   1. [Naming](#naming)
   1. [Declaration](#declaration)
   1. [Alignment](#alignment)
@@ -24,11 +27,12 @@
   - Only include one React component per file.
     - However, multiple [Stateless, or Pure, Components](https://facebook.github.io/react/docs/reusable-components.html#stateless-functions) are allowed per file. eslint: [`react/no-multi-comp`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-multi-comp.md#ignorestateless).
   - Always use JSX syntax.
-  - Do not use `React.createElement` unless you're initializing the app from a file that is not JSX.
+  - Do not use `React.createElement` unless you’re initializing the app from a file that is not JSX.
+  - [`react/forbid-prop-types`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/forbid-prop-types.md) will allow `arrays` and `objects` only if it is explicitly noted what `array` and `object` contains, using `arrayOf`, `objectOf`, or `shape`.
 
 ## Class vs `React.createClass` vs stateless
 
-  - If you have internal state and/or refs, prefer `class extends React.Component` over `React.createClass` unless you have a very good reason to use mixins. eslint: [`react/prefer-es6-class`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-es6-class.md) [`react/prefer-stateless-function`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-stateless-function.md)
+  - If you have internal state and/or refs, prefer `class extends React.Component` over `React.createClass`. eslint: [`react/prefer-es6-class`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-es6-class.md) [`react/prefer-stateless-function`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-stateless-function.md)
 
     ```jsx
     // bad
@@ -48,7 +52,7 @@
     }
     ```
 
-    And if you don't have state or refs, prefer normal functions (not arrow functions) over classes:
+    And if you don’t have state or refs, prefer normal functions (not arrow functions) over classes:
 
     ```jsx
     // bad
@@ -69,9 +73,15 @@
     }
     ```
 
+## Mixins
+
+  - [Do not use mixins](https://facebook.github.io/react/blog/2016/07/13/mixins-considered-harmful.html).
+
+  > Why? Mixins introduce implicit dependencies, cause name clashes, and cause snowballing complexity. Most use cases for mixins can be accomplished in better ways via components, higher-order components, or utility modules.
+
 ## Naming
 
-  - **Extensions**: Use `.jsx` extension for React components.
+  - **Extensions**: Use `.jsx` extension for React components. eslint: [`react/jsx-filename-extension`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-filename-extension.md)
   - **Filename**: Use PascalCase for filenames. E.g., `ReservationCard.jsx`.
   - **Reference Naming**: Use PascalCase for React components and camelCase for their instances. eslint: [`react/jsx-pascal-case`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-pascal-case.md)
 
@@ -101,9 +111,10 @@
     // good
     import Footer from './Footer';
     ```
-  - **Higher-order Component Naming**: Use a composite of the higher-order component's name and the passed-in component's name as the `displayName` on the generated component. For example, the higher-order component `withFoo()`, when passed a component `Bar` should produce a component with a `displayName` of `withFoo(Bar)`.
 
-  > Why? A component's `displayName` may be used by developer tools or in error messages, and having a value that clearly expresses this relationship helps people understand what is happening.
+  - **Higher-order Component Naming**: Use a composite of the higher-order component’s name and the passed-in component’s name as the `displayName` on the generated component. For example, the higher-order component `withFoo()`, when passed a component `Bar` should produce a component with a `displayName` of `withFoo(Bar)`.
+
+    > Why? A component’s `displayName` may be used by developer tools or in error messages, and having a value that clearly expresses this relationship helps people understand what is happening.
 
     ```jsx
     // bad
@@ -127,6 +138,22 @@
       return WithFoo;
     }
     ```
+
+  - **Props Naming**: Avoid using DOM component prop names for different purposes.
+
+    > Why? People expect props like `style` and `className` to mean one specific thing. Varying this API for a subset of your app makes the code less readable and less maintainable, and may cause bugs.
+
+    ```jsx
+    // bad
+    <MyComponent style="fancy" />
+
+    // bad
+    <MyComponent className="fancy" />
+
+    // good
+    <MyComponent variant="fancy" />
+    ```
+
 ## Declaration
 
   - Do not use `displayName` for naming components. Instead, name the component by reference.
@@ -145,7 +172,7 @@
 
 ## Alignment
 
-  - Follow these alignment styles for JSX syntax. eslint: [`react/jsx-closing-bracket-location`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-bracket-location.md)
+  - Follow these alignment styles for JSX syntax. eslint: [`react/jsx-closing-bracket-location`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-bracket-location.md) [`react/jsx-closing-tag-location`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-tag-location.md)
 
     ```jsx
     // bad
@@ -168,14 +195,32 @@
     >
       <Quux />
     </Foo>
+
+    // bad
+    {showButton &&
+      <Button />
+    }
+
+    // bad
+    {
+      showButton &&
+        <Button />
+    }
+
+    // good
+    {showButton && (
+      <Button />
+    )}
+
+    // good
+    {showButton && <Button />}
     ```
 
 ## Quotes
 
-  - Always use double quotes (`"`) for JSX attributes, but single quotes for all other JS. eslint: [`jsx-quotes`](http://eslint.org/docs/rules/jsx-quotes)
+  - Always use double quotes (`"`) for JSX attributes, but single quotes (`'`) for all other JS. eslint: [`jsx-quotes`](https://eslint.org/docs/rules/jsx-quotes)
 
-  > Why? JSX attributes [can't contain escaped quotes](http://eslint.org/docs/rules/jsx-quotes), so double quotes make contractions like `"don't"` easier to type.
-  > Regular HTML attributes also typically use double quotes instead of single, so JSX attributes mirror this convention.
+    > Why? Regular HTML attributes also typically use double quotes instead of single, so JSX attributes mirror this convention.
 
     ```jsx
     // bad
@@ -193,7 +238,7 @@
 
 ## Spacing
 
-  - Always include a single space in your self-closing tag.
+  - Always include a single space in your self-closing tag. eslint: [`no-multi-spaces`](https://eslint.org/docs/rules/no-multi-spaces), [`react/jsx-tag-spacing`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-tag-spacing.md)
 
     ```jsx
     // bad
@@ -250,9 +295,12 @@
     <Foo
       hidden
     />
+
+    // good
+    <Foo hidden />
     ```
 
-  - Always include an `alt` prop on `<img>` tags. If the image is presentational, `alt` can be an empty string or the `<img>` must have `role="presentation"`. eslint: [`jsx-a11y/img-has-alt`](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/img-has-alt.md)
+  - Always include an `alt` prop on `<img>` tags. If the image is presentational, `alt` can be an empty string or the `<img>` must have `role="presentation"`. eslint: [`jsx-a11y/alt-text`](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/alt-text.md)
 
     ```jsx
     // bad
@@ -270,7 +318,7 @@
 
   - Do not use words like "image", "photo", or "picture" in `<img>` `alt` props. eslint: [`jsx-a11y/img-redundant-alt`](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/img-redundant-alt.md)
 
-  > Why? Screenreaders already announce `img` elements as images, so there is no need to include this information in the alt text.
+    > Why? Screenreaders already announce `img` elements as images, so there is no need to include this information in the alt text.
 
     ```jsx
     // bad
@@ -280,7 +328,7 @@
     <img src="hello.jpg" alt="Me waving hello" />
     ```
 
-  - Use only valid, non-abstract [ARIA roles](https://www.w3.org/TR/wai-aria/roles#role_definitions). eslint: [`jsx-a11y/aria-role`](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-role.md)
+  - Use only valid, non-abstract [ARIA roles](https://www.w3.org/TR/wai-aria/#usage_intro). eslint: [`jsx-a11y/aria-role`](https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-role.md)
 
     ```jsx
     // bad - not an ARIA role
@@ -305,7 +353,11 @@
   <div />
   ```
 
-  - Avoid using an array index as `key` prop, prefer a unique ID. ([why?](https://medium.com/@robinpokorny/index-as-a-key-is-an-anti-pattern-e0349aece318))
+  - Avoid using an array index as `key` prop, prefer a stable ID. eslint: [`react/no-array-index-key`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-array-index-key.md)
+
+> Why? Not using a stable ID [is an anti-pattern](https://medium.com/@robinpokorny/index-as-a-key-is-an-anti-pattern-e0349aece318) because it can negatively impact performance and cause issues with component state.
+
+We don’t recommend using indexes for keys if the order of items may change.
 
   ```jsx
   // bad
@@ -325,6 +377,88 @@
   ))}
   ```
 
+  - Always define explicit defaultProps for all non-required props.
+
+  > Why? propTypes are a form of documentation, and providing defaultProps means the reader of your code doesn’t have to assume as much. In addition, it can mean that your code can omit certain type checks.
+
+  ```jsx
+  // bad
+  function SFC({ foo, bar, children }) {
+    return <div>{foo}{bar}{children}</div>;
+  }
+  SFC.propTypes = {
+    foo: PropTypes.number.isRequired,
+    bar: PropTypes.string,
+    children: PropTypes.node,
+  };
+
+  // good
+  function SFC({ foo, bar, children }) {
+    return <div>{foo}{bar}{children}</div>;
+  }
+  SFC.propTypes = {
+    foo: PropTypes.number.isRequired,
+    bar: PropTypes.string,
+    children: PropTypes.node,
+  };
+  SFC.defaultProps = {
+    bar: '',
+    children: null,
+  };
+  ```
+
+  - Use spread props sparingly.
+  > Why? Otherwise you’re more likely to pass unnecessary props down to components. And for React v15.6.1 and older, you could [pass invalid HTML attributes to the DOM](https://reactjs.org/blog/2017/09/08/dom-attributes-in-react-16.html).
+
+  Exceptions:
+
+  - HOCs that proxy down props and hoist propTypes
+
+  ```jsx
+  function HOC(WrappedComponent) {
+    return class Proxy extends React.Component {
+      Proxy.propTypes = {
+        text: PropTypes.string,
+        isLoading: PropTypes.bool
+      };
+
+      render() {
+        return <WrappedComponent {...this.props} />
+      }
+    }
+  }
+  ```
+
+  - Spreading objects with known, explicit props. This can be particularly useful when testing React components with Mocha’s beforeEach construct.
+
+  ```jsx
+  export default function Foo {
+    const props = {
+      text: '',
+      isPublished: false
+    }
+
+    return (<div {...props} />);
+  }
+  ```
+
+  Notes for use:
+  Filter out unnecessary props when possible. Also, use [prop-types-exact](https://www.npmjs.com/package/prop-types-exact) to help prevent bugs.
+
+  ```jsx
+  // bad
+  render() {
+    const { irrelevantProp, ...relevantProps } = this.props;
+    return <WrappedComponent {...this.props} />
+  }
+
+  // good
+  render() {
+    const { irrelevantProp, ...relevantProps } = this.props;
+    return <WrappedComponent {...relevantProps} />
+  }
+  ```
+
 ## Refs
 
   - Always use ref callbacks. eslint: [`react/no-string-refs`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-string-refs.md)
@@ -337,18 +471,18 @@
 
     // good
     <Foo
-      ref={(ref) => this.myRef = ref}
+      ref={(ref) => { this.myRef = ref; }}
     />
     ```
 
 ## Parentheses
 
-  - Wrap JSX tags in parentheses when they span more than one line. eslint: [`react/wrap-multilines`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/wrap-multilines.md)
+  - Wrap JSX tags in parentheses when they span more than one line. eslint: [`react/jsx-wrap-multilines`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-wrap-multilines.md)
 
     ```jsx
     // bad
     render() {
-      return <MyComponent className="long body" foo="bar">
+      return <MyComponent variant="long body" foo="bar">
                <MyChild />
              </MyComponent>;
     }
@@ -356,7 +490,7 @@
     // good
     render() {
       return (
-        <MyComponent className="long body" foo="bar">
+        <MyComponent variant="long body" foo="bar">
           <MyChild />
         </MyComponent>
       );
@@ -375,13 +509,13 @@
 
     ```jsx
     // bad
-    <Foo className="stuff"></Foo>
+    <Foo variant="stuff"></Foo>
 
     // good
-    <Foo className="stuff" />
+    <Foo variant="stuff" />
     ```
 
-  - If your component has multi-line properties, close its tag on a new line. eslint: [`react/jsx-closing-bracket-location`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-bracket-location.md)
+  - If your component has multiline properties, close its tag on a new line. eslint: [`react/jsx-closing-bracket-location`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-closing-bracket-location.md)
 
     ```jsx
     // bad
@@ -398,7 +532,7 @@
 
 ## Methods
 
-  - Use arrow functions to close over local variables.
+  - Use arrow functions to close over local variables. It is handy when you need to pass additional data to an event handler. Although, make sure they [do not massively hurt performance](https://www.bignerdranch.com/blog/choosing-the-best-approach-for-react-event-handlers/), in particular when passed to custom components that might be PureComponents, because they will trigger a possibly needless rerender every time.
 
     ```jsx
     function ItemList(props) {
@@ -407,7 +541,7 @@
           {props.items.map((item, index) => (
             <Item
               key={item.key}
-              onClick={() => doSomethingWith(item.name, index)}
+              onClick={(event) => { doSomethingWith(event, item.name, index); }}
             />
           ))}
         </ul>
@@ -417,7 +551,7 @@
 
   - Bind event handlers for the render method in the constructor. eslint: [`react/jsx-no-bind`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-bind.md)
 
-  > Why? A bind call in the render path creates a brand new function on every single render.
+    > Why? A bind call in the render path creates a brand new function on every single render. Do not use arrow functions in class fields, because it makes them [challenging to test and debug, and can negatively impact performance](https://medium.com/@charpeni/arrow-functions-in-class-properties-might-not-be-as-great-as-we-think-3b3551c440b1), and because conceptually, class fields are for data, not logic.
 
     ```jsx
     // bad
@@ -427,7 +561,18 @@
       }
 
       render() {
-        return <div onClick={this.onClickDiv.bind(this)} />
+        return <div onClick={this.onClickDiv.bind(this)} />;
+      }
+    }
+
+    // very bad
+    class extends React.Component {
+      onClickDiv = () => {
+        // do stuff
+      }
+
+      render() {
+        return <div onClick={this.onClickDiv} />
       }
     }
 
@@ -444,12 +589,13 @@
       }
 
       render() {
-        return <div onClick={this.onClickDiv} />
+        return <div onClick={this.onClickDiv} />;
       }
     }
     ```
 
   - Do not use underscore prefix for internal methods of a React component.
+    > Why? Underscore prefixes are sometimes used as a convention in other languages to denote privacy. But, unlike those languages, there is no native support for privacy in JavaScript, everything is public. Regardless of your intentions, adding underscore prefixes to your properties does not actually make them private, and any property (underscore-prefixed or not) should be treated as being public. See issues [#1024](https://github.com/airbnb/javascript/issues/1024), and [#490](https://github.com/airbnb/javascript/issues/490) for a more in-depth discussion.
 
     ```jsx
     // bad
@@ -471,7 +617,7 @@
     }
     ```
 
-  - Be sure to return a value in your `render` methods. eslint: [`require-render-return`](https://github.com/yannickcr/eslint-plugin-react/pull/502)
+  - Be sure to return a value in your `render` methods. eslint: [`react/require-render-return`](https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/require-render-return.md)
 
     ```jsx
     // bad
@@ -501,13 +647,14 @@
   1. `componentWillUnmount`
   1. *clickHandlers or eventHandlers* like `onClickSubmit()` or `onChangeDescription()`
   1. *getter methods for `render`* like `getSelectReason()` or `getFooterContent()`
-  1. *Optional render methods* like `renderNavigation()` or `renderProfilePicture()`
+  1. *optional render methods* like `renderNavigation()` or `renderProfilePicture()`
   1. `render`
 
   - How to define `propTypes`, `defaultProps`, `contextTypes`, etc...
 
     ```jsx
-    import React, { PropTypes } from 'react';
+    import React from 'react';
+    import PropTypes from 'prop-types';
 
     const propTypes = {
       id: PropTypes.number.isRequired,
@@ -525,7 +672,7 @@
       }
 
       render() {
-        return <a href={this.props.url} data-id={this.props.id}>{this.props.text}</a>
+        return <a href={this.props.url} data-id={this.props.id}>{this.props.text}</a>;
       }
     }
 
@@ -556,7 +703,7 @@
   1. `componentWillUnmount`
   1. *clickHandlers or eventHandlers* like `onClickSubmit()` or `onChangeDescription()`
   1. *getter methods for `render`* like `getSelectReason()` or `getFooterContent()`
-  1. *Optional render methods* like `renderNavigation()` or `renderProfilePicture()`
+  1. *optional render methods* like `renderNavigation()` or `renderProfilePicture()`
   1. `render`
 
 ## `isMounted`
@@ -571,9 +718,17 @@
 
   This JSX/React style guide is also available in other languages:
 
-  - ![cn](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/China.png) **Chinese (Simplified)**: [JasonBoy/javascript](https://github.com/JasonBoy/javascript/tree/master/react)
-  - ![pl](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Poland.png) **Polish**: [pietraszekl/javascript](https://github.com/pietraszekl/javascript/tree/master/react)
+  - ![cn](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/China.png) **Chinese (Simplified)**: [jhcccc/javascript](https://github.com/jhcccc/javascript/tree/master/react)
+  - ![tw](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Taiwan.png) **Chinese (Traditional)**: [jigsawye/javascript](https://github.com/jigsawye/javascript/tree/master/react)
+  - ![es](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Spain.png) **Español**: [agrcrobles/javascript](https://github.com/agrcrobles/javascript/tree/master/react)
+  - ![jp](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Japan.png) **Japanese**: [mitsuruog/javascript-style-guide](https://github.com/mitsuruog/javascript-style-guide/tree/master/react)
   - ![kr](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/South-Korea.png) **Korean**: [apple77y/javascript](https://github.com/apple77y/javascript/tree/master/react)
+  - ![pl](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Poland.png) **Polish**: [pietraszekl/javascript](https://github.com/pietraszekl/javascript/tree/master/react)
   - ![Br](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Brazil.png) **Portuguese**: [ronal2do/javascript](https://github.com/ronal2do/airbnb-react-styleguide)
+  - ![ru](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Russia.png) **Russian**: [leonidlebedev/javascript-airbnb](https://github.com/leonidlebedev/javascript-airbnb/tree/master/react)
+  - ![th](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Thailand.png) **Thai**: [lvarayut/javascript-style-guide](https://github.com/lvarayut/javascript-style-guide/tree/master/react)
+  - ![tr](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Turkey.png) **Turkish**: [alioguzhan/react-style-guide](https://github.com/alioguzhan/react-style-guide)
+  - ![ua](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Ukraine.png) **Ukrainian**: [ivanzusko/javascript](https://github.com/ivanzusko/javascript/tree/master/react)
+  - ![vn](https://raw.githubusercontent.com/gosquared/flags/master/flags/flags/shiny/24/Vietnam.png) **Vietnam**: [uetcodecamp/jsx-style-guide](https://github.com/UETCodeCamp/jsx-style-guide)
 
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