diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000000..db6f34c77c
--- /dev/null
+++ b/.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
diff --git a/.github/workflows/node-pretest.yml b/.github/workflows/node-pretest.yml
new file mode 100644
index 0000000000..48c68f5955
--- /dev/null
+++ b/.github/workflows/node-pretest.yml
@@ -0,0 +1,26 @@
+name: 'Tests: pretest/posttest'
+
+on: [pull_request, push]
+
+jobs:
+ pretest:
+ runs-on: ubuntu-latest
+ strategy:
+ fail-fast: false
+ matrix:
+ package:
+ - '..'
+ - eslint-config-airbnb
+ - eslint-config-airbnb-base
+
+ defaults:
+ run:
+ working-directory: "packages/${{ matrix.package }}"
+
+ steps:
+ - uses: actions/checkout@v2
+ - uses: ljharb/actions/node/install@main
+ name: 'nvm install lts/* && npm install'
+ with:
+ node-version: 'lts/*'
+ - run: npm run pretest
diff --git a/.github/workflows/node.yml b/.github/workflows/node.yml
new file mode 100644
index 0000000000..6fc77ea08d
--- /dev/null
+++ b/.github/workflows/node.yml
@@ -0,0 +1,163 @@
+name: 'Tests: node.js'
+
+on: [pull_request, push]
+
+jobs:
+ matrix:
+ runs-on: ubuntu-latest
+ outputs:
+ latest: ${{ steps.set-matrix.outputs.requireds }}
+ steps:
+ - uses: ljharb/actions/node/matrix@main
+ id: set-matrix
+ with:
+ versionsAsRoot: true
+ type: 'majors'
+ preset: '^12 || ^14 || ^16 || >= 17'
+
+ base:
+ needs: [matrix]
+ name: 'base config'
+ runs-on: ubuntu-latest
+
+ strategy:
+ fail-fast: false
+ matrix:
+ node-version: ${{ fromJson(needs.matrix.outputs.latest) }}
+ eslint:
+ - 8
+ - 7
+ package:
+ - eslint-config-airbnb-base
+ exclude:
+ - node-version: 10
+ eslint: 8
+ package: eslint-config-airbnb-base
+
+ defaults:
+ run:
+ working-directory: "packages/${{ matrix.package }}"
+
+ steps:
+ - uses: actions/checkout@v2
+ - uses: ljharb/actions/node/install@main
+ name: 'nvm install ${{ matrix.node-version }} && npm install'
+ with:
+ before_install: cd "packages/${{ matrix.package }}"
+ node-version: ${{ matrix.node-version }}
+ after_install: |
+ npm install --no-save "eslint@${{ matrix.eslint }}"
+ - run: node -pe "require('eslint/package.json').version"
+ name: 'eslint version'
+ - run: npm run travis
+ - uses: codecov/codecov-action@v2
+
+ react:
+ needs: [matrix]
+ name: 'react config'
+ runs-on: ubuntu-latest
+
+ strategy:
+ fail-fast: false
+ matrix:
+ node-version: ${{ fromJson(needs.matrix.outputs.latest) }}
+ eslint:
+ - 8
+ - 7
+ package:
+ - eslint-config-airbnb
+ react-hooks:
+ - 4
+
+ defaults:
+ run:
+ working-directory: "packages/${{ matrix.package }}"
+
+ steps:
+ - uses: actions/checkout@v2
+ - uses: ljharb/actions/node/install@main
+ name: 'nvm install ${{ matrix.node-version }} && npm install'
+ with:
+ before_install: cd "packages/${{ matrix.package }}"
+ node-version: ${{ matrix.node-version }}
+ after_install: |
+ npm install --no-save "eslint@${{ matrix.eslint }}"
+ - run: node -pe "require('eslint/package.json').version"
+ name: 'eslint version'
+ - run: npm install --no-save "eslint-plugin-react-hooks@${{ matrix.react-hooks }}"
+ if: ${{ matrix.react-hooks > 0}}
+ - run: npm run travis
+ - uses: codecov/codecov-action@v2
+
+ prepublish-base:
+ name: 'prepublish tests (base config)'
+ runs-on: ubuntu-latest
+ strategy:
+ fail-fast: false
+ matrix:
+ eslint:
+ - 8
+ - 7
+ package:
+ - eslint-config-airbnb-base
+
+ defaults:
+ run:
+ working-directory: "packages/${{ matrix.package }}"
+
+ steps:
+ - uses: actions/checkout@v2
+ - uses: ljharb/actions/node/install@main
+ name: 'nvm install lts/* && npm install'
+ with:
+ before_install: cd "packages/${{ matrix.package }}"
+ node-version: lts/*
+ after_install: |
+ npm install --no-save "eslint@${{ matrix.eslint }}"
+ - run: node -pe "require('eslint/package.json').version"
+ name: 'eslint version'
+ - run: npm run pretravis
+ - run: npm run prepublishOnly
+ - run: npm run posttravis
+
+ prepublish-react:
+ name: 'prepublish tests (react config)'
+ runs-on: ubuntu-latest
+ strategy:
+ fail-fast: false
+ matrix:
+ eslint:
+ - 8
+ - 7
+ package:
+ - eslint-config-airbnb
+ react-hooks:
+ - 4
+
+ defaults:
+ run:
+ working-directory: "packages/${{ matrix.package }}"
+
+ steps:
+ - uses: actions/checkout@v2
+ - uses: ljharb/actions/node/install@main
+ name: 'nvm install lts/* && npm install'
+ with:
+ before_install: cd "packages/${{ matrix.package }}"
+ node-version: lts/*
+ after_install: |
+ npm install --no-save "eslint@${{ matrix.eslint }}"
+ - run: npm install --no-save "eslint-plugin-react-hooks@${{ matrix.react-hooks }}"
+ if: ${{ matrix.react-hooks > 0}}
+ - run: node -pe "require('eslint/package.json').version"
+ name: 'eslint version'
+ - run: npm run pretravis
+ - run: npm run prepublishOnly
+ - run: npm run posttravis
+
+ node:
+ name: 'node 10+'
+ needs: [base, prepublish-base, react, prepublish-react]
+ runs-on: ubuntu-latest
+ steps:
+ - run: 'echo tests completed'
diff --git a/.github/workflows/rebase.yml b/.github/workflows/rebase.yml
new file mode 100644
index 0000000000..027aed0797
--- /dev/null
+++ b/.github/workflows/rebase.yml
@@ -0,0 +1,15 @@
+name: Automatic Rebase
+
+on: [pull_request_target]
+
+jobs:
+ _:
+ name: "Automatic Rebase"
+
+ runs-on: ubuntu-latest
+
+ steps:
+ - uses: actions/checkout@v2
+ - uses: ljharb/rebase@master
+ env:
+ GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/require-allow-edits.yml b/.github/workflows/require-allow-edits.yml
new file mode 100644
index 0000000000..549d7b4823
--- /dev/null
+++ b/.github/workflows/require-allow-edits.yml
@@ -0,0 +1,12 @@
+name: Require “Allow Edits”
+
+on: [pull_request_target]
+
+jobs:
+ _:
+ name: "Require “Allow Edits”"
+
+ runs-on: ubuntu-latest
+
+ steps:
+ - uses: ljharb/require-allow-edits@main
diff --git a/.gitignore b/.gitignore
index 3c3629e647..ac10dfe528 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,7 @@
+# gitignore
+
node_modules
+
+# Only apps should have lockfiles
+yarn.lock
+package-lock.json
diff --git a/.npmrc b/.npmrc
new file mode 100644
index 0000000000..43c97e719a
--- /dev/null
+++ b/.npmrc
@@ -0,0 +1 @@
+package-lock=false
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 773761966a..0000000000
--- a/.travis.yml
+++ /dev/null
@@ -1,17 +0,0 @@
-language: node_js
-node_js:
- - "6"
- - "5"
- - "4"
-env:
- - 'TEST_DIR=packages/eslint-config-airbnb'
- - 'TEST_DIR=packages/eslint-config-airbnb-base'
-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'
-script:
- - 'npm run travis'
-sudo: false
-matrix:
- fast_finish: true
diff --git a/LICENSE.md b/LICENSE.md
new file mode 100644
index 0000000000..69d80c0252
--- /dev/null
+++ b/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.
diff --git a/README.md b/README.md
index 1ed011d564..9a325a355b 100644
--- a/README.md
+++ b/README.md
@@ -2,16 +2,21 @@
*A mostly reasonable approach to JavaScript*
+> **Note**: this guide assumes you are using [Babel](https://babeljs.io), and requires that you use [babel-preset-airbnb](https://npmjs.com/babel-preset-airbnb) or the equivalent. It also assumes you are installing shims/polyfills in your app, with [airbnb-browser-shims](https://npmjs.com/airbnb-browser-shims) or the equivalent.
+
[](https://www.npmjs.com/package/eslint-config-airbnb)
[](https://www.npmjs.com/package/eslint-config-airbnb-base)
-[](https://gitter.im/airbnb/javascript?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+[](https://gitter.im/airbnb/javascript?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+
+This guide is available in other languages too. See [Translation](#translation)
Other Style Guides
- - [ES5 (Deprecated)](https://github.com/airbnb/javascript/tree/es5-deprecated/es5)
- - [React](react/)
- - [CSS-in-JavaScript](css-in-javascript/)
- - [CSS & Sass](https://github.com/airbnb/css)
- - [Ruby](https://github.com/airbnb/ruby)
+
+ - [ES5 (Deprecated)](https://github.com/airbnb/javascript/tree/es5-deprecated/es5)
+ - [React](react/)
+ - [CSS-in-JavaScript](css-in-javascript/)
+ - [CSS & Sass](https://github.com/airbnb/css)
+ - [Ruby](https://github.com/airbnb/ruby)
## Table of Contents
@@ -31,6 +36,7 @@ Other Style Guides
1. [Hoisting](#hoisting)
1. [Comparison Operators & Equality](#comparison-operators--equality)
1. [Blocks](#blocks)
+ 1. [Control Statements](#control-statements)
1. [Comments](#comments)
1. [Whitespace](#whitespace)
1. [Commas](#commas)
@@ -42,6 +48,7 @@ Other Style Guides
1. [jQuery](#jquery)
1. [ECMAScript 5 Compatibility](#ecmascript-5-compatibility)
1. [ECMAScript 6+ (ES 2015+) Styles](#ecmascript-6-es-2015-styles)
+ 1. [Standard Library](#standard-library)
1. [Testing](#testing)
1. [Performance](#performance)
1. [Resources](#resources)
@@ -51,17 +58,22 @@ Other Style Guides
1. [Chat With Us About JavaScript](#chat-with-us-about-javascript)
1. [Contributors](#contributors)
1. [License](#license)
+ 1. [Amendments](#amendments)
## Types
- [1.1](#types--primitives) **Primitives**: When you access a primitive type you work directly on its value.
- + `string`
- + `number`
- + `boolean`
- + `null`
- + `undefined`
+ - `string`
+ - `number`
+ - `boolean`
+ - `null`
+ - `undefined`
+ - `symbol`
+ - `bigint`
+
+
```javascript
const foo = 1;
@@ -72,12 +84,16 @@ Other Style Guides
console.log(foo, bar); // => 1, 9
```
+ - Symbols and BigInts cannot be faithfully polyfilled, so they should not be used when targeting browsers/environments that don’t support them natively.
+
- [1.2](#types--complex) **Complex**: When you access a complex type you work on a reference to its value.
- + `object`
- + `array`
- + `function`
+ - `object`
+ - `array`
+ - `function`
+
+
```javascript
const foo = [1, 2];
@@ -93,9 +109,9 @@ Other Style Guides
## References
- - [2.1](#references--prefer-const) Use `const` for all of your references; avoid using `var`. eslint: [`prefer-const`](http://eslint.org/docs/rules/prefer-const.html), [`no-const-assign`](http://eslint.org/docs/rules/no-const-assign.html)
+ - [2.1](#references--prefer-const) Use `const` for all of your references; avoid using `var`. eslint: [`prefer-const`](https://eslint.org/docs/rules/prefer-const), [`no-const-assign`](https://eslint.org/docs/rules/no-const-assign)
- > Why? This ensures that you can't reassign your references, which can lead to bugs and difficult to comprehend code.
+ > Why? This ensures that you can’t reassign your references, which can lead to bugs and difficult to comprehend code.
```javascript
// bad
@@ -108,7 +124,7 @@ Other Style Guides
```
- - [2.2](#references--disallow-var) If you must reassign references, use `let` instead of `var`. eslint: [`no-var`](http://eslint.org/docs/rules/no-var.html) jscs: [`disallowVar`](http://jscs.info/rule/disallowVar)
+ - [2.2](#references--disallow-var) If you must reassign references, use `let` instead of `var`. eslint: [`no-var`](https://eslint.org/docs/rules/no-var)
> Why? `let` is block-scoped rather than function-scoped like `var`.
@@ -127,24 +143,28 @@ Other Style Guides
```
- - [2.3](#references--block-scope) Note that both `let` and `const` are block-scoped.
+ - [2.3](#references--block-scope) Note that both `let` and `const` are block-scoped, whereas `var` is function-scoped.
```javascript
// const and let only exist in the blocks they are defined in.
{
let a = 1;
const b = 1;
+ var c = 1;
}
console.log(a); // ReferenceError
console.log(b); // ReferenceError
+ console.log(c); // Prints 1
```
+ In the above code, you can see that referencing `a` and `b` will produce a ReferenceError, while `c` contains the number. This is because `a` and `b` are block scoped, while `c` is scoped to the containing function.
+
**[⬆ back to top](#table-of-contents)**
## Objects
- - [3.1](#objects--no-new) Use the literal syntax for object creation. eslint: [`no-new-object`](http://eslint.org/docs/rules/no-new-object.html)
+ - [3.1](#objects--no-new) Use the literal syntax for object creation. eslint: [`no-new-object`](https://eslint.org/docs/rules/no-new-object)
```javascript
// bad
@@ -181,7 +201,7 @@ Other Style Guides
```
- - [3.3](#es6-object-shorthand) Use object method shorthand. eslint: [`object-shorthand`](http://eslint.org/docs/rules/object-shorthand.html) jscs: [`requireEnhancedObjectLiterals`](http://jscs.info/rule/requireEnhancedObjectLiterals)
+ - [3.3](#es6-object-shorthand) Use object method shorthand. eslint: [`object-shorthand`](https://eslint.org/docs/rules/object-shorthand)
```javascript
// bad
@@ -204,9 +224,9 @@ Other Style Guides
```
- - [3.4](#es6-object-concise) Use property value shorthand. eslint: [`object-shorthand`](http://eslint.org/docs/rules/object-shorthand.html) jscs: [`requireEnhancedObjectLiterals`](http://jscs.info/rule/requireEnhancedObjectLiterals)
+ - [3.4](#es6-object-concise) Use property value shorthand. eslint: [`object-shorthand`](https://eslint.org/docs/rules/object-shorthand)
- > Why? It is shorter to write and descriptive.
+ > Why? It is shorter and descriptive.
```javascript
const lukeSkywalker = 'Luke Skywalker';
@@ -225,7 +245,7 @@ Other Style Guides
- [3.5](#objects--grouped-shorthand) Group your shorthand properties at the beginning of your object declaration.
- > Why? It's easier to tell which properties are using the shorthand.
+ > Why? It’s easier to tell which properties are using the shorthand.
```javascript
const anakinSkywalker = 'Anakin Skywalker';
@@ -253,72 +273,78 @@ Other Style Guides
```
- - [3.6](#objects--quoted-props) Only quote properties that are invalid identifiers. eslint: [`quote-props`](http://eslint.org/docs/rules/quote-props.html) jscs: [`disallowQuotedKeysInObjects`](http://jscs.info/rule/disallowQuotedKeysInObjects)
-
- > Why? In general we consider it subjectively easier to read. It improves syntax highlighting, and is also more easily optimized by many JS engines.
-
- ```javascript
- // bad
- const bad = {
- 'foo': 3,
- 'bar': 4,
- 'data-blah': 5,
- };
-
- // good
- const good = {
- foo: 3,
- bar: 4,
- 'data-blah': 5,
- };
- ```
+ - [3.6](#objects--quoted-props) Only quote properties that are invalid identifiers. eslint: [`quote-props`](https://eslint.org/docs/rules/quote-props)
+
+ > Why? In general we consider it subjectively easier to read. It improves syntax highlighting, and is also more easily optimized by many JS engines.
+
+ ```javascript
+ // bad
+ const bad = {
+ 'foo': 3,
+ 'bar': 4,
+ 'data-blah': 5,
+ };
+
+ // good
+ const good = {
+ foo: 3,
+ bar: 4,
+ 'data-blah': 5,
+ };
+ ```
- - [3.7](#objects--prototype-builtins) Do not call `Object.prototype` methods directly, such as `hasOwnProperty`, `propertyIsEnumerable`, and `isPrototypeOf`.
+ - [3.7](#objects--prototype-builtins) Do not call `Object.prototype` methods directly, such as `hasOwnProperty`, `propertyIsEnumerable`, and `isPrototypeOf`. eslint: [`no-prototype-builtins`](https://eslint.org/docs/rules/no-prototype-builtins)
- > Why? These methods may be shadowed by properties on the object in question - consider `{ hasOwnProperty: false }` - or, the object may be a null object (`Object.create(null)`).
+ > Why? These methods may be shadowed by properties on the object in question - consider `{ hasOwnProperty: false }` - or, the object may be a null object (`Object.create(null)`). In modern browsers that support ES2022, or with a polyfill such as , `Object.hasOwn` can also be used as an alternative to `Object.prototype.hasOwnProperty.call`.
- ```javascript
- // bad
- console.log(object.hasOwnProperty(key));
+ ```javascript
+ // bad
+ console.log(object.hasOwnProperty(key));
+
+ // good
+ console.log(Object.prototype.hasOwnProperty.call(object, key));
- // good
- console.log(Object.prototype.hasOwnProperty.call(object, key));
+ // better
+ const has = Object.prototype.hasOwnProperty; // cache the lookup once, in module scope.
+ console.log(has.call(object, key));
+
+ // best
+ console.log(Object.hasOwn(object, key)); // only supported in browsers that support ES2022
- // best
- const has = Object.prototype.hasOwnProperty; // cache the lookup once, in module scope.
- /* or */
- import has from 'has';
- …
- console.log(has.call(object, key));
- ```
+ /* or */
+ import has from 'has'; // https://www.npmjs.com/package/has
+ console.log(has(object, key));
+ /* or */
+ console.log(Object.hasOwn(object, key)); // https://www.npmjs.com/package/object.hasown
+ ```
- - [3.8](#objects--rest-spread) Prefer the object spread operator over [`Object.assign`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) to shallow-copy objects. Use the object rest operator to get a new object with certain properties omitted.
+ - [3.8](#objects--rest-spread) Prefer the object spread syntax over [`Object.assign`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/assign) to shallow-copy objects. Use the object rest parameter syntax to get a new object with certain properties omitted. eslint: [`prefer-object-spread`](https://eslint.org/docs/rules/prefer-object-spread)
- ```javascript
- // very bad
- const original = { a: 1, b: 2 };
- const copy = Object.assign(original, { c: 3 }); // this mutates `original` ಠ_ಠ
- delete copy.a; // so does this
+ ```javascript
+ // very bad
+ const original = { a: 1, b: 2 };
+ const copy = Object.assign(original, { c: 3 }); // this mutates `original` ಠ_ಠ
+ delete copy.a; // so does this
- // bad
- const original = { a: 1, b: 2 };
- const copy = Object.assign({}, original, { c: 3 }); // copy => { a: 1, b: 2, c: 3 }
+ // bad
+ const original = { a: 1, b: 2 };
+ const copy = Object.assign({}, original, { c: 3 }); // copy => { a: 1, b: 2, c: 3 }
- // good
- const original = { a: 1, b: 2 };
- const copy = { ...original, c: 3 }; // copy => { a: 1, b: 2, c: 3 }
+ // good
+ const original = { a: 1, b: 2 };
+ const copy = { ...original, c: 3 }; // copy => { a: 1, b: 2, c: 3 }
- const { a, ...noA } = copy; // noA => { b: 2, c: 3 }
- ```
+ const { a, ...noA } = copy; // noA => { b: 2, c: 3 }
+ ```
**[⬆ back to top](#table-of-contents)**
## Arrays
- - [4.1](#arrays--literals) Use the literal syntax for array creation. eslint: [`no-array-constructor`](http://eslint.org/docs/rules/no-array-constructor.html)
+ - [4.1](#arrays--literals) Use the literal syntax for array creation. eslint: [`no-array-constructor`](https://eslint.org/docs/rules/no-array-constructor)
```javascript
// bad
@@ -350,7 +376,7 @@ Other Style Guides
const itemsCopy = [];
let i;
- for (i = 0; i < len; i++) {
+ for (i = 0; i < len; i += 1) {
itemsCopy[i] = items[i];
}
@@ -358,16 +384,46 @@ Other Style Guides
const itemsCopy = [...items];
```
-
- - [4.4](#arrays--from) To convert an array-like object to an array, use [Array.from](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/from).
+
+
+ - [4.4](#arrays--from-iterable) To convert an iterable object to an array, use spreads `...` instead of [`Array.from`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/from)
```javascript
const foo = document.querySelectorAll('.foo');
+
+ // good
const nodes = Array.from(foo);
+
+ // best
+ const nodes = [...foo];
+ ```
+
+
+ - [4.5](#arrays--from-array-like) Use [`Array.from`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/from) for converting an array-like object to an array.
+
+ ```javascript
+ const arrLike = { 0: 'foo', 1: 'bar', 2: 'baz', length: 3 };
+
+ // bad
+ const arr = Array.prototype.slice.call(arrLike);
+
+ // good
+ const arr = Array.from(arrLike);
+ ```
+
+
+ - [4.6](#arrays--mapping) Use [`Array.from`](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/from) instead of spread `...` for mapping over iterables, because it avoids creating an intermediate array.
+
+ ```javascript
+ // bad
+ const baz = [...foo].map(bar);
+
+ // good
+ const baz = Array.from(foo, bar);
```
- - [4.5](#arrays--callback-return) Use return statements in array method callbacks. It's ok to omit the return if the function body consists of a single statement following [8.2](#8.2). eslint: [`array-callback-return`](http://eslint.org/docs/rules/array-callback-return)
+ - [4.7](#arrays--callback-return) Use return statements in array method callbacks. It’s ok to omit the return if the function body consists of a single statement returning an expression without side effects, following [8.2](#arrows--implicit-return). eslint: [`array-callback-return`](https://eslint.org/docs/rules/array-callback-return)
```javascript
// good
@@ -377,20 +433,16 @@ Other Style Guides
});
// good
- [1, 2, 3].map(x => x + 1);
+ [1, 2, 3].map((x) => x + 1);
- // bad
- const flat = {};
- [[0, 1], [2, 3], [4, 5]].reduce((memo, item, index) => {
- const flatten = memo.concat(item);
- flat[index] = flatten;
+ // bad - no returned value means `acc` becomes undefined after the first iteration
+ [[0, 1], [2, 3], [4, 5]].reduce((acc, item, index) => {
+ const flatten = acc.concat(item);
});
// good
- const flat = {};
- [[0, 1], [2, 3], [4, 5]].reduce((memo, item, index) => {
- const flatten = memo.concat(item);
- flat[index] = flatten;
+ [[0, 1], [2, 3], [4, 5]].reduce((acc, item, index) => {
+ const flatten = acc.concat(item);
return flatten;
});
@@ -415,14 +467,51 @@ Other Style Guides
});
```
+
+ - [4.8](#arrays--bracket-newline) Use line breaks after opening array brackets and before closing array brackets, if an array has multiple lines
+
+ ```javascript
+ // bad
+ const arr = [
+ [0, 1], [2, 3], [4, 5],
+ ];
+
+ const objectInArray = [{
+ id: 1,
+ }, {
+ id: 2,
+ }];
+
+ const numberInArray = [
+ 1, 2,
+ ];
+
+ // good
+ const arr = [[0, 1], [2, 3], [4, 5]];
+
+ const objectInArray = [
+ {
+ id: 1,
+ },
+ {
+ id: 2,
+ },
+ ];
+
+ const numberInArray = [
+ 1,
+ 2,
+ ];
+ ```
+
**[⬆ back to top](#table-of-contents)**
## Destructuring
- - [5.1](#destructuring--object) Use object destructuring when accessing and using multiple properties of an object. jscs: [`requireObjectDestructuring`](http://jscs.info/rule/requireObjectDestructuring)
+ - [5.1](#destructuring--object) Use object destructuring when accessing and using multiple properties of an object. eslint: [`prefer-destructuring`](https://eslint.org/docs/rules/prefer-destructuring)
- > Why? Destructuring saves you from creating temporary references for those properties.
+ > Why? Destructuring saves you from creating temporary references for those properties, and from repetitive access of the object. Repeating object access creates more repetitive code, requires more reading, and creates more opportunities for mistakes. Destructuring objects also provides a single site of definition of the object structure that is used in the block, rather than requiring reading the entire block to determine what is used.
```javascript
// bad
@@ -446,7 +535,7 @@ Other Style Guides
```
- - [5.2](#destructuring--array) Use array destructuring. jscs: [`requireArrayDestructuring`](http://jscs.info/rule/requireArrayDestructuring)
+ - [5.2](#destructuring--array) Use array destructuring. eslint: [`prefer-destructuring`](https://eslint.org/docs/rules/prefer-destructuring)
```javascript
const arr = [1, 2, 3, 4];
@@ -460,7 +549,7 @@ Other Style Guides
```
- - [5.3](#destructuring--object-over-array) Use object destructuring for multiple return values, not array destructuring. jscs: [`disallowArrayDestructuringReturn`](http://jscs.info/rule/disallowArrayDestructuringReturn)
+ - [5.3](#destructuring--object-over-array) Use object destructuring for multiple return values, not array destructuring.
> Why? You can add new properties over time or change the order of things without breaking call sites.
@@ -484,13 +573,12 @@ Other Style Guides
const { left, top } = processInput(input);
```
-
**[⬆ back to top](#table-of-contents)**
## Strings
- - [6.1](#strings--quotes) Use single quotes `''` for strings. eslint: [`quotes`](http://eslint.org/docs/rules/quotes.html) jscs: [`validateQuoteMarks`](http://jscs.info/rule/validateQuoteMarks)
+ - [6.1](#strings--quotes) Use single quotes `''` for strings. eslint: [`quotes`](https://eslint.org/docs/rules/quotes)
```javascript
// bad
@@ -525,7 +613,7 @@ Other Style Guides
```
- - [6.3](#es6-template-literals) When programmatically building up strings, use template strings instead of concatenation. eslint: [`prefer-template`](http://eslint.org/docs/rules/prefer-template.html) [`template-curly-spacing`](http://eslint.org/docs/rules/template-curly-spacing) jscs: [`requireTemplateStrings`](http://jscs.info/rule/requireTemplateStrings)
+ - [6.3](#es6-template-literals) When programmatically building up strings, use template strings instead of concatenation. eslint: [`prefer-template`](https://eslint.org/docs/rules/prefer-template) [`template-curly-spacing`](https://eslint.org/docs/rules/template-curly-spacing)
> Why? Template strings give you a readable, concise syntax with proper newlines and string interpolation features.
@@ -552,10 +640,10 @@ Other Style Guides
```
- - [6.4](#strings--eval) Never use `eval()` on a string, it opens too many vulnerabilities.
+ - [6.4](#strings--eval) Never use `eval()` on a string; it opens too many vulnerabilities. eslint: [`no-eval`](https://eslint.org/docs/rules/no-eval)
- - [6.5](#strings--escaping) Do not unnecessarily escape characters in strings. eslint: [`no-useless-escape`](http://eslint.org/docs/rules/no-useless-escape)
+ - [6.5](#strings--escaping) Do not unnecessarily escape characters in strings. eslint: [`no-useless-escape`](https://eslint.org/docs/rules/no-useless-escape)
> Why? Backslashes harm readability, thus they should only be present when necessary.
@@ -565,35 +653,38 @@ Other Style Guides
// good
const foo = '\'this\' is "quoted"';
- const foo = `'this' is "quoted"`;
+ const foo = `my name is '${name}'`;
```
**[⬆ back to top](#table-of-contents)**
-
## Functions
- - [7.1](#functions--declarations) Use named function expressions instead of function declarations. eslint: [`func-style`](http://eslint.org/docs/rules/func-style) jscs: [`requireFunctionDeclarations`](http://jscs.info/rule/requireFunctionDeclarations)
+ - [7.1](#functions--declarations) Use named function expressions instead of function declarations. eslint: [`func-style`](https://eslint.org/docs/rules/func-style), [`func-names`](https://eslint.org/docs/latest/rules/func-names)
- > Why? Function declarations are hoisted, which means that it’s easy - too easy - to reference the function before it is defined in the file. This harms readability and maintainability. If you find that a function’s definition is large or complex enough that it is interfering with understanding the rest of the file, then perhaps it’s time to extract it to its own module! Don’t forget to name the expression - anonymous functions can make it harder to locate the problem in an Error's call stack.
+ > Why? Function declarations are hoisted, which means that it’s easy - too easy - to reference the function before it is defined in the file. This harms readability and maintainability. If you find that a function’s definition is large or complex enough that it is interfering with understanding the rest of the file, then perhaps it’s time to extract it to its own module! Don’t forget to explicitly name the expression, regardless of whether or not the name is inferred from the containing variable (which is often the case in modern browsers or when using compilers such as Babel). This eliminates any assumptions made about the Error’s call stack. ([Discussion](https://github.com/airbnb/javascript/issues/794))
```javascript
- // bad
- const foo = function () {
- };
-
// bad
function foo() {
+ // ...
}
+ // bad
+ const foo = function () {
+ // ...
+ };
+
// good
- const foo = function bar() {
+ // lexical name distinguished from the variable-referenced invocation(s)
+ const short = function longUniqueMoreDescriptiveLexicalFoo() {
+ // ...
};
```
- - [7.2](#functions--iife) Wrap immediately invoked function expressions in parentheses. eslint: [`wrap-iife`](http://eslint.org/docs/rules/wrap-iife.html) jscs: [`requireParenthesesAroundIIFE`](http://jscs.info/rule/requireParenthesesAroundIIFE)
+ - [7.2](#functions--iife) Wrap immediately invoked function expressions in parentheses. eslint: [`wrap-iife`](https://eslint.org/docs/rules/wrap-iife)
> Why? An immediately invoked function expression is a single unit - wrapping both it, and its invocation parens, in parens, cleanly expresses this. Note that in a world with modules everywhere, you almost never need an IIFE.
@@ -605,10 +696,10 @@ Other Style Guides
```
- - [7.3](#functions--in-blocks) Never declare a function in a non-function block (if, while, etc). Assign the function to a variable instead. Browsers will allow you to do it, but they all interpret it differently, which is bad news bears. eslint: [`no-loop-func`](http://eslint.org/docs/rules/no-loop-func.html)
+ - [7.3](#functions--in-blocks) Never declare a function in a non-function block (`if`, `while`, etc). Assign the function to a variable instead. Browsers will allow you to do it, but they all interpret it differently, which is bad news bears. eslint: [`no-loop-func`](https://eslint.org/docs/rules/no-loop-func)
- - [7.4](#functions--note-on-blocks) **Note:** ECMA-262 defines a `block` as a list of statements. A function declaration is not a statement. [Read ECMA-262's note on this issue](http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf#page=97).
+ - [7.4](#functions--note-on-blocks) **Note:** ECMA-262 defines a `block` as a list of statements. A function declaration is not a statement.
```javascript
// bad
@@ -632,18 +723,18 @@ Other Style Guides
```javascript
// bad
- function nope(name, options, arguments) {
- // ...stuff...
+ function foo(name, options, arguments) {
+ // ...
}
// good
- function yup(name, options, args) {
- // ...stuff...
+ function foo(name, options, args) {
+ // ...
}
```
- - [7.6](#es6-rest) Never use `arguments`, opt to use rest syntax `...` instead. eslint: [`prefer-rest-params`](http://eslint.org/docs/rules/prefer-rest-params)
+ - [7.6](#es6-rest) Never use `arguments`, opt to use rest syntax `...` instead. eslint: [`prefer-rest-params`](https://eslint.org/docs/rules/prefer-rest-params)
> Why? `...` is explicit about which arguments you want pulled. Plus, rest arguments are a real Array, and not merely Array-like like `arguments`.
@@ -666,7 +757,7 @@ Other Style Guides
```javascript
// really bad
function handleThings(opts) {
- // No! We shouldn't mutate function arguments.
+ // No! We shouldn’t mutate function arguments.
// Double bad: if opts is falsy it'll be set to an object which may
// be what you want but it can introduce subtle bugs.
opts = opts || {};
@@ -693,7 +784,7 @@ Other Style Guides
> Why? They are confusing to reason about.
```javascript
- var b = 1;
+ let b = 1;
// bad
function count(a = b++) {
console.log(a);
@@ -705,7 +796,7 @@ Other Style Guides
```
- - [7.9](#functions--defaults-last) Always put default parameters last.
+ - [7.9](#functions--defaults-last) Always put default parameters last. eslint: [`default-param-last`](https://eslint.org/docs/rules/default-param-last)
```javascript
// bad
@@ -720,20 +811,20 @@ Other Style Guides
```
- - [7.10](#functions--constructor) Never use the Function constructor to create a new function. eslint: [`no-new-func`](http://eslint.org/docs/rules/no-new-func)
+ - [7.10](#functions--constructor) Never use the Function constructor to create a new function. eslint: [`no-new-func`](https://eslint.org/docs/rules/no-new-func)
- > Why? Creating a function in this way evaluates a string similarly to eval(), which opens vulnerabilities.
+ > Why? Creating a function in this way evaluates a string similarly to `eval()`, which opens vulnerabilities.
```javascript
// bad
- var add = new Function('a', 'b', 'return a + b');
+ const add = new Function('a', 'b', 'return a + b');
// still bad
- var subtract = Function('a', 'b', 'return a - b');
+ const subtract = Function('a', 'b', 'return a - b');
```
- - [7.11](#functions--signature-spacing) Spacing in a function signature. eslint: [`space-before-function-paren`](http://eslint.org/docs/rules/space-before-function-paren) [`space-before-blocks`](http://eslint.org/docs/rules/space-before-blocks)
+ - [7.11](#functions--signature-spacing) Spacing in a function signature. eslint: [`space-before-function-paren`](https://eslint.org/docs/rules/space-before-function-paren) [`space-before-blocks`](https://eslint.org/docs/rules/space-before-blocks)
> Why? Consistency is good, and you shouldn’t have to add or remove a space when adding or removing a name.
@@ -749,7 +840,7 @@ Other Style Guides
```
- - [7.12](#functions--mutate-params) Never mutate parameters. eslint: [`no-param-reassign`](http://eslint.org/docs/rules/no-param-reassign.html)
+ - [7.12](#functions--mutate-params) Never mutate parameters. eslint: [`no-param-reassign`](https://eslint.org/docs/rules/no-param-reassign)
> Why? Manipulating objects passed in as parameters can cause unwanted variable side effects in the original caller.
@@ -757,16 +848,16 @@ Other Style Guides
// bad
function f1(obj) {
obj.key = 1;
- };
+ }
// good
function f2(obj) {
const key = Object.prototype.hasOwnProperty.call(obj, 'key') ? obj.key : 1;
- };
+ }
```
- - [7.13](#functions--reassign-params) Never reassign parameters. eslint: [`no-param-reassign`](http://eslint.org/docs/rules/no-param-reassign.html)
+ - [7.13](#functions--reassign-params) Never reassign parameters. eslint: [`no-param-reassign`](https://eslint.org/docs/rules/no-param-reassign)
> Why? Reassigning parameters can lead to unexpected behavior, especially when accessing the `arguments` object. It can also cause optimization issues, especially in V8.
@@ -774,25 +865,29 @@ Other Style Guides
// bad
function f1(a) {
a = 1;
+ // ...
}
function f2(a) {
if (!a) { a = 1; }
+ // ...
}
// good
function f3(a) {
const b = a || 1;
+ // ...
}
function f4(a = 1) {
+ // ...
}
```
- - [7.14](#functions--spread-vs-apply) Prefer the use of the spread operator `...` to call variadic functions. eslint: [`prefer-spread`](http://eslint.org/docs/rules/prefer-spread)
+ - [7.14](#functions--spread-vs-apply) Prefer the use of the spread syntax `...` to call variadic functions. eslint: [`prefer-spread`](https://eslint.org/docs/rules/prefer-spread)
- > Why? It's cleaner, you don't need to supply a context, and you can not easily compose `new` with `apply`.
+ > Why? It’s cleaner, you don’t need to supply a context, and you can not easily compose `new` with `apply`.
```javascript
// bad
@@ -804,21 +899,21 @@ Other Style Guides
console.log(...x);
// bad
- new (Function.prototype.bind.apply(Date, [null, 2016, 08, 05]));
+ new (Function.prototype.bind.apply(Date, [null, 2016, 8, 5]));
// good
- new Date(...[2016, 08, 05]);
+ new Date(...[2016, 8, 5]);
```
- - [7.15](#functions--signature-invocation-indentation) Functions with multiline signatures, or invocations, should be indented just like every other multiline list in this guide: with each item on a line by itself, with a trailing comma on the last item.
+ - [7.15](#functions--signature-invocation-indentation) Functions with multiline signatures, or invocations, should be indented just like every other multiline list in this guide: with each item on a line by itself, with a trailing comma on the last item. eslint: [`function-paren-newline`](https://eslint.org/docs/rules/function-paren-newline)
```javascript
// bad
function foo(bar,
baz,
quux) {
- // body
+ // ...
}
// good
@@ -827,7 +922,7 @@ Other Style Guides
baz,
quux,
) {
- // body
+ // ...
}
// bad
@@ -848,11 +943,11 @@ Other Style Guides
## Arrow Functions
- - [8.1](#arrows--use-them) When you must use function expressions (as when passing an anonymous function), use arrow function notation. eslint: [`prefer-arrow-callback`](http://eslint.org/docs/rules/prefer-arrow-callback.html), [`arrow-spacing`](http://eslint.org/docs/rules/arrow-spacing.html) jscs: [`requireArrowFunctions`](http://jscs.info/rule/requireArrowFunctions)
+ - [8.1](#arrows--use-them) When you must use an anonymous function (as when passing an inline callback), use arrow function notation. eslint: [`prefer-arrow-callback`](https://eslint.org/docs/rules/prefer-arrow-callback), [`arrow-spacing`](https://eslint.org/docs/rules/arrow-spacing)
> Why? It creates a version of the function that executes in the context of `this`, which is usually what you want, and is a more concise syntax.
- > Why not? If you have a fairly complicated function, you might move that logic out into its own function declaration.
+ > Why not? If you have a fairly complicated function, you might move that logic out into its own named function expression.
```javascript
// bad
@@ -869,19 +964,19 @@ Other Style Guides
```
- - [8.2](#arrows--implicit-return) If the function body consists of a single expression, omit the braces and use the implicit return. Otherwise, keep the braces and use a `return` statement. eslint: [`arrow-parens`](http://eslint.org/docs/rules/arrow-parens.html), [`arrow-body-style`](http://eslint.org/docs/rules/arrow-body-style.html) jscs: [`disallowParenthesesAroundArrowParam`](http://jscs.info/rule/disallowParenthesesAroundArrowParam), [`requireShorthandArrowFunctions`](http://jscs.info/rule/requireShorthandArrowFunctions)
+ - [8.2](#arrows--implicit-return) If the function body consists of a single statement returning an [expression](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Expressions_and_Operators#Expressions) without side effects, omit the braces and use the implicit return. Otherwise, keep the braces and use a `return` statement. eslint: [`arrow-parens`](https://eslint.org/docs/rules/arrow-parens), [`arrow-body-style`](https://eslint.org/docs/rules/arrow-body-style)
> Why? Syntactic sugar. It reads well when multiple functions are chained together.
```javascript
// bad
- [1, 2, 3].map(number => {
+ [1, 2, 3].map((number) => {
const nextNumber = number + 1;
`A string containing the ${nextNumber}.`;
});
// good
- [1, 2, 3].map(number => `A string containing the ${number}.`);
+ [1, 2, 3].map((number) => `A string containing the ${number + 1}.`);
// good
[1, 2, 3].map((number) => {
@@ -891,8 +986,26 @@ Other Style Guides
// good
[1, 2, 3].map((number, index) => ({
- [index]: number
+ [index]: number,
}));
+
+ // No implicit return with side effects
+ function foo(callback) {
+ const val = callback();
+ if (val === true) {
+ // Do something if callback returns true
+ }
+ }
+
+ let bool = false;
+
+ // bad
+ foo(() => bool = true);
+
+ // good
+ foo(() => {
+ bool = true;
+ });
```
@@ -900,40 +1013,45 @@ Other Style Guides
> Why? It shows clearly where the function starts and ends.
- ```js
+ ```javascript
// bad
- ['get', 'post', 'put'].map(httpMethod => Object.prototype.hasOwnProperty.call(
+ ['get', 'post', 'put'].map((httpMethod) => Object.prototype.hasOwnProperty.call(
httpMagicObjectWithAVeryLongName,
- httpMethod
+ httpMethod,
)
);
// good
- ['get', 'post', 'put'].map(httpMethod => (
+ ['get', 'post', 'put'].map((httpMethod) => (
Object.prototype.hasOwnProperty.call(
httpMagicObjectWithAVeryLongName,
- httpMethod
+ httpMethod,
)
));
```
- - [8.4](#arrows--one-arg-parens) If your function takes a single argument and doesn’t use braces, omit the parentheses. Otherwise, always include parentheses around arguments. eslint: [`arrow-parens`](http://eslint.org/docs/rules/arrow-parens.html) jscs: [`disallowParenthesesAroundArrowParam`](http://jscs.info/rule/disallowParenthesesAroundArrowParam)
+ - [8.4](#arrows--one-arg-parens) Always include parentheses around arguments for clarity and consistency. eslint: [`arrow-parens`](https://eslint.org/docs/rules/arrow-parens)
- > Why? Less visual clutter.
+ > Why? Minimizes diff churn when adding or removing arguments.
- ```js
+ ```javascript
// bad
- [1, 2, 3].map((x) => x * x);
-
- // good
[1, 2, 3].map(x => x * x);
// good
+ [1, 2, 3].map((x) => x * x);
+
+ // bad
[1, 2, 3].map(number => (
`A long string with the ${number}. It’s so long that we don’t want it to take up space on the .map line!`
));
+ // good
+ [1, 2, 3].map((number) => (
+ `A long string with the ${number}. It’s so long that we don’t want it to take up space on the .map line!`
+ ));
+
// bad
[1, 2, 3].map(x => {
const y = x + 1;
@@ -948,27 +1066,45 @@ Other Style Guides
```
- - [8.5](#arrows--confusing) Avoid confusing arrow function syntax (`=>`) with comparison operators (`<=`, `>=`). eslint: [`no-confusing-arrow`](http://eslint.org/docs/rules/no-confusing-arrow)
+ - [8.5](#arrows--confusing) Avoid confusing arrow function syntax (`=>`) with comparison operators (`<=`, `>=`). eslint: [`no-confusing-arrow`](https://eslint.org/docs/rules/no-confusing-arrow)
- ```js
+ ```javascript
// bad
- const itemHeight = item => item.height > 256 ? item.largeSize : item.smallSize;
+ const itemHeight = (item) => item.height <= 256 ? item.largeSize : item.smallSize;
// bad
- const itemHeight = (item) => item.height > 256 ? item.largeSize : item.smallSize;
+ const itemHeight = (item) => item.height >= 256 ? item.largeSize : item.smallSize;
// good
- const itemHeight = item => (item.height > 256 ? item.largeSize : item.smallSize);
+ const itemHeight = (item) => (item.height <= 256 ? item.largeSize : item.smallSize);
// good
const itemHeight = (item) => {
const { height, largeSize, smallSize } = item;
- return height > 256 ? largeSize : smallSize;
+ return height <= 256 ? largeSize : smallSize;
};
```
-**[⬆ back to top](#table-of-contents)**
+
+ - [8.6](#whitespace--implicit-arrow-linebreak) Enforce the location of arrow function bodies with implicit returns. eslint: [`implicit-arrow-linebreak`](https://eslint.org/docs/rules/implicit-arrow-linebreak)
+
+ ```javascript
+ // bad
+ (foo) =>
+ bar;
+
+ (foo) =>
+ (bar);
+ // good
+ (foo) => bar;
+ (foo) => (bar);
+ (foo) => (
+ bar
+ )
+ ```
+
+**[⬆ back to top](#table-of-contents)**
## Classes & Constructors
@@ -988,7 +1124,6 @@ Other Style Guides
return value;
};
-
// good
class Queue {
constructor(contents = []) {
@@ -1015,13 +1150,13 @@ Other Style Guides
}
inherits(PeekableQueue, Queue);
PeekableQueue.prototype.peek = function () {
- return this._queue[0];
- }
+ return this.queue[0];
+ };
// good
class PeekableQueue extends Queue {
peek() {
- return this._queue[0];
+ return this.queue[0];
}
}
```
@@ -1063,9 +1198,8 @@ Other Style Guides
.setHeight(20);
```
-
- - [9.4](#constructors--tostring) It's okay to write a custom toString() method, just make sure it works successfully and causes no side effects.
+ - [9.4](#constructors--tostring) It’s okay to write a custom `toString()` method, just make sure it works successfully and causes no side effects.
```javascript
class Jedi {
@@ -1084,7 +1218,7 @@ Other Style Guides
```
- - [9.5](#constructors--no-useless) Classes have a default constructor if one is not specified. An empty constructor function or one that just delegates to a parent class is unnecessary. eslint: [`no-useless-constructor`](http://eslint.org/docs/rules/no-useless-constructor)
+ - [9.5](#constructors--no-useless) Classes have a default constructor if one is not specified. An empty constructor function or one that just delegates to a parent class is unnecessary. eslint: [`no-useless-constructor`](https://eslint.org/docs/rules/no-useless-constructor)
```javascript
// bad
@@ -1113,7 +1247,7 @@ Other Style Guides
```
- - [9.6](#classes--no-duplicate-members) Avoid duplicate class members. eslint: [`no-dupe-class-members`](http://eslint.org/docs/rules/no-dupe-class-members)
+ - [9.6](#classes--no-duplicate-members) Avoid duplicate class members. eslint: [`no-dupe-class-members`](https://eslint.org/docs/rules/no-dupe-class-members)
> Why? Duplicate class member declarations will silently prefer the last one - having duplicates is almost certainly a bug.
@@ -1135,16 +1269,47 @@ Other Style Guides
}
```
+
+ - [9.7](#classes--methods-use-this) Class methods should use `this` or be made into a static method unless an external library or framework requires using specific non-static methods. Being an instance method should indicate that it behaves differently based on properties of the receiver. eslint: [`class-methods-use-this`](https://eslint.org/docs/rules/class-methods-use-this)
-**[⬆ back to top](#table-of-contents)**
+ ```javascript
+ // bad
+ class Foo {
+ bar() {
+ console.log('bar');
+ }
+ }
+
+ // good - this is used
+ class Foo {
+ bar() {
+ console.log(this.bar);
+ }
+ }
+
+ // good - constructor is exempt
+ class Foo {
+ constructor() {
+ // ...
+ }
+ }
+
+ // good - static methods aren't expected to use this
+ class Foo {
+ static bar() {
+ console.log('bar');
+ }
+ }
+ ```
+**[⬆ back to top](#table-of-contents)**
## Modules
- [10.1](#modules--use-them) Always use modules (`import`/`export`) over a non-standard module system. You can always transpile to your preferred module system.
- > Why? Modules are the future, let's start using the future now.
+ > Why? Modules are the future, let’s start using the future now.
```javascript
// bad
@@ -1191,7 +1356,7 @@ Other Style Guides
- [10.4](#modules--no-duplicate-imports) Only import from a path in one place.
- eslint: [`no-duplicate-imports`](http://eslint.org/docs/rules/no-duplicate-imports)
+ eslint: [`no-duplicate-imports`](https://eslint.org/docs/rules/no-duplicate-imports)
> Why? Having multiple lines that import from the same path can make code harder to maintain.
```javascript
@@ -1212,22 +1377,23 @@ Other Style Guides
- [10.5](#modules--no-mutable-exports) Do not export mutable bindings.
- eslint: [`import/no-mutable-exports`](https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-mutable-exports.md)
+ eslint: [`import/no-mutable-exports`](https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-mutable-exports.md)
> Why? Mutation should be avoided in general, but in particular when exporting mutable bindings. While this technique may be needed for some special cases, in general, only constant references should be exported.
```javascript
// bad
let foo = 3;
- export { foo }
+ export { foo };
// good
const foo = 3;
- export { foo }
+ export { foo };
```
- [10.6](#modules--prefer-default-export) In modules with a single export, prefer default export over named export.
- eslint: [`import/prefer-default-export`](https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/prefer-default-export.md)
+ eslint: [`import/prefer-default-export`](https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/prefer-default-export.md)
+ > Why? To encourage more files that only ever export one thing, which is better for readability and maintainability.
```javascript
// bad
@@ -1239,7 +1405,7 @@ Other Style Guides
- [10.7](#modules--imports-first) Put all `import`s above non-import statements.
- eslint: [`import/imports-first`](https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/imports-first.md)
+ eslint: [`import/first`](https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/first.md)
> Why? Since `import`s are hoisted, keeping them all at the top prevents surprising behavior.
```javascript
@@ -1258,6 +1424,7 @@ Other Style Guides
- [10.8](#modules--multiline-imports-over-newlines) Multiline imports should be indented just like multiline array and object literals.
+ eslint: [`object-curly-newline`](https://eslint.org/docs/rules/object-curly-newline)
> Why? The curly braces follow the same indentation rules as every other curly brace block in the style guide, as do the trailing commas.
@@ -1277,7 +1444,7 @@ Other Style Guides
- [10.9](#modules--no-webpack-loader-syntax) Disallow Webpack loader syntax in module import statements.
- eslint: [`import/no-webpack-loader-syntax`](https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-webpack-loader-syntax.md)
+ eslint: [`import/no-webpack-loader-syntax`](https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-webpack-loader-syntax.md)
> Why? Since using Webpack syntax in the imports couples the code to a module bundler. Prefer using the loader syntax in `webpack.config.js`.
```javascript
@@ -1290,12 +1457,29 @@ Other Style Guides
import barCss from 'bar.css';
```
+
+ - [10.10](#modules--import-extensions) Do not include JavaScript filename extensions
+ eslint: [`import/extensions`](https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/extensions.md)
+ > Why? Including extensions inhibits refactoring, and inappropriately hardcodes implementation details of the module you're importing in every consumer.
+
+ ```javascript
+ // bad
+ import foo from './foo.js';
+ import bar from './bar.jsx';
+ import baz from './baz/index.jsx';
+
+ // good
+ import foo from './foo';
+ import bar from './bar';
+ import baz from './baz';
+ ```
+
**[⬆ back to top](#table-of-contents)**
## Iterators and Generators
- - [11.1](#iterators--nope) Don't use iterators. Prefer JavaScript's higher-order functions instead of loops like `for-in` or `for-of`. eslint: [`no-iterator`](http://eslint.org/docs/rules/no-iterator.html) [`no-restricted-syntax`](http://eslint.org/docs/rules/no-restricted-syntax)
+ - [11.1](#iterators--nope) Don’t use iterators. Prefer JavaScript’s higher-order functions instead of loops like `for-in` or `for-of`. eslint: [`no-iterator`](https://eslint.org/docs/rules/no-iterator) [`no-restricted-syntax`](https://eslint.org/docs/rules/no-restricted-syntax)
> Why? This enforces our immutable rule. Dealing with pure functions that return values is easier to reason about than side effects.
@@ -1309,75 +1493,107 @@ Other Style Guides
for (let num of numbers) {
sum += num;
}
-
sum === 15;
// good
let sum = 0;
- numbers.forEach(num => sum += num);
+ numbers.forEach((num) => {
+ sum += num;
+ });
sum === 15;
// best (use the functional force)
const sum = numbers.reduce((total, num) => total + num, 0);
sum === 15;
+
+ // bad
+ const increasedByOne = [];
+ for (let i = 0; i < numbers.length; i++) {
+ increasedByOne.push(numbers[i] + 1);
+ }
+
+ // good
+ const increasedByOne = [];
+ numbers.forEach((num) => {
+ increasedByOne.push(num + 1);
+ });
+
+ // best (keeping it functional)
+ const increasedByOne = numbers.map((num) => num + 1);
```
- - [11.2](#generators--nope) Don't use generators for now.
+ - [11.2](#generators--nope) Don’t use generators for now.
- > Why? They don't transpile well to ES5.
+ > Why? They don’t transpile well to ES5.
- - [11.3](#generators--spacing) If you must use generators, or if you disregard [our advice](#generators--nope), make sure their function signature is spaced properly. eslint: [`generator-star-spacing`](http://eslint.org/docs/rules/generator-star-spacing)
+ - [11.3](#generators--spacing) If you must use generators, or if you disregard [our advice](#generators--nope), make sure their function signature is spaced properly. eslint: [`generator-star-spacing`](https://eslint.org/docs/rules/generator-star-spacing)
> Why? `function` and `*` are part of the same conceptual keyword - `*` is not a modifier for `function`, `function*` is a unique construct, different from `function`.
- ```js
+ ```javascript
// bad
function * foo() {
+ // ...
}
+ // bad
const bar = function * () {
- }
+ // ...
+ };
+ // bad
const baz = function *() {
- }
+ // ...
+ };
+ // bad
const quux = function*() {
- }
+ // ...
+ };
+ // bad
function*foo() {
+ // ...
}
+ // bad
function *foo() {
+ // ...
}
// very bad
function
*
foo() {
+ // ...
}
+ // very bad
const wat = function
*
() {
- }
+ // ...
+ };
// good
function* foo() {
+ // ...
}
+ // good
const foo = function* () {
- }
+ // ...
+ };
```
**[⬆ back to top](#table-of-contents)**
-
## Properties
- - [12.1](#properties--dot) Use dot notation when accessing properties. eslint: [`dot-notation`](http://eslint.org/docs/rules/dot-notation.html) jscs: [`requireDotNotation`](http://jscs.info/rule/requireDotNotation)
+ - [12.1](#properties--dot) Use dot notation when accessing properties. eslint: [`dot-notation`](https://eslint.org/docs/rules/dot-notation)
```javascript
const luke = {
@@ -1408,13 +1624,23 @@ Other Style Guides
const isJedi = getProp('jedi');
```
-**[⬆ back to top](#table-of-contents)**
+
+ - [12.3](#es2016-properties--exponentiation-operator) Use exponentiation operator `**` when calculating exponentiations. eslint: [`prefer-exponentiation-operator`](https://eslint.org/docs/rules/prefer-exponentiation-operator).
+ ```javascript
+ // bad
+ const binary = Math.pow(2, 10);
+
+ // good
+ const binary = 2 ** 10;
+ ```
+
+**[⬆ back to top](#table-of-contents)**
## Variables
- - [13.1](#variables--const) Always use `const` to declare variables. Not doing so will result in global variables. We want to avoid polluting the global namespace. Captain Planet warned us of that. eslint: [`no-undef`](http://eslint.org/docs/rules/no-undef) [`prefer-const`](http://eslint.org/docs/rules/prefer-const)
+ - [13.1](#variables--const) Always use `const` or `let` to declare variables. Not doing so will result in global variables. We want to avoid polluting the global namespace. Captain Planet warned us of that. eslint: [`no-undef`](https://eslint.org/docs/rules/no-undef) [`prefer-const`](https://eslint.org/docs/rules/prefer-const)
```javascript
// bad
@@ -1425,9 +1651,9 @@ Other Style Guides
```
- - [13.2](#variables--one-const) Use one `const` declaration per variable. eslint: [`one-var`](http://eslint.org/docs/rules/one-var.html) jscs: [`disallowMultipleVarDecl`](http://jscs.info/rule/disallowMultipleVarDecl)
+ - [13.2](#variables--one-const) Use one `const` or `let` declaration per variable or assignment. eslint: [`one-var`](https://eslint.org/docs/rules/one-var)
- > Why? It's easier to add new variable declarations this way, and you never have to worry about swapping out a `;` for a `,` or introducing punctuation-only diffs. You can also step through each declaration with the debugger, instead of jumping through all of them at once.
+ > Why? It’s easier to add new variable declarations this way, and you never have to worry about swapping out a `;` for a `,` or introducing punctuation-only diffs. You can also step through each declaration with the debugger, instead of jumping through all of them at once.
```javascript
// bad
@@ -1450,7 +1676,7 @@ Other Style Guides
- [13.3](#variables--const-let-group) Group all your `const`s and then group all your `let`s.
- > Why? This is helpful when later on you might need to assign a variable depending on one of the previous assigned variables.
+ > Why? This is helpful when later on you might need to assign a variable depending on one of the previously assigned variables.
```javascript
// bad
@@ -1511,8 +1737,9 @@ Other Style Guides
return name;
}
```
+
- - [13.5](#variables--no-chain-assignment) Don't chain variable assignments.
+ - [13.5](#variables--no-chain-assignment) Don’t chain variable assignments. eslint: [`no-multi-assign`](https://eslint.org/docs/rules/no-multi-assign)
> Why? Chaining variable assignments creates implicit global variables.
@@ -1526,7 +1753,7 @@ Other Style Guides
let a = b = c = 1;
}());
- console.log(a); // undefined
+ console.log(a); // throws ReferenceError
console.log(b); // 1
console.log(c); // 1
@@ -1537,57 +1764,119 @@ Other Style Guides
let c = a;
}());
- console.log(a); // undefined
- console.log(b); // undefined
- console.log(c); // undefined
+ console.log(a); // throws ReferenceError
+ console.log(b); // throws ReferenceError
+ console.log(c); // throws ReferenceError
// the same applies for `const`
```
- - [13.6](#variables--unary-increment-decrement) Avoid using unary increments and decrements (++, --). eslint [`no-plusplus`](http://eslint.org/docs/rules/no-plusplus)
+ - [13.6](#variables--unary-increment-decrement) Avoid using unary increments and decrements (`++`, `--`). eslint [`no-plusplus`](https://eslint.org/docs/rules/no-plusplus)
- > Why? Per the eslint documentation, unary increment and decrement statements are subject to automatic semicolon insertion and can cause silent errors with incrementing or decrementing values within an application. It is also more expressive to mutate your values with statements like `num += 1` instead of `num ++`. Disallowing unary increment and decrement statements also prevents you from pre-incrementing/pre-decrementing values unintentionally which can also cause unexpected behavior in your programs.
+ > Why? Per the eslint documentation, unary increment and decrement statements are subject to automatic semicolon insertion and can cause silent errors with incrementing or decrementing values within an application. It is also more expressive to mutate your values with statements like `num += 1` instead of `num++` or `num ++`. Disallowing unary increment and decrement statements also prevents you from pre-incrementing/pre-decrementing values unintentionally which can also cause unexpected behavior in your programs.
```javascript
- // bad
+ // bad
- let array = [1, 2, 3];
- let num = 1;
- num ++;
- -- num;
+ const array = [1, 2, 3];
+ let num = 1;
+ num++;
+ --num;
- let sum = 0;
- let truthyCount = 0;
- for(let i = 0; i < array.length; i++){
- let value = array[i];
- sum += value;
- if (value) {
- truthyCount++;
- }
+ let sum = 0;
+ let truthyCount = 0;
+ for (let i = 0; i < array.length; i++) {
+ let value = array[i];
+ sum += value;
+ if (value) {
+ truthyCount++;
}
+ }
- // good
+ // good
- let array = [1, 2, 3];
- let num = 1;
- num += 1;
- num -= 1;
+ const array = [1, 2, 3];
+ let num = 1;
+ num += 1;
+ num -= 1;
- const sum = array.reduce((a, b) => a + b, 0);
- const truthyCount = array.filter(Boolean).length;
+ const sum = array.reduce((a, b) => a + b, 0);
+ const truthyCount = array.filter(Boolean).length;
```
-**[⬆ back to top](#table-of-contents)**
+
+ - [13.7](#variables--linebreak) Avoid linebreaks before or after `=` in an assignment. If your assignment violates [`max-len`](https://eslint.org/docs/rules/max-len), surround the value in parens. eslint [`operator-linebreak`](https://eslint.org/docs/rules/operator-linebreak).
+
+ > Why? Linebreaks surrounding `=` can obfuscate the value of an assignment.
+
+ ```javascript
+ // bad
+ const foo =
+ superLongLongLongLongLongLongLongLongFunctionName();
+
+ // bad
+ const foo
+ = 'superLongLongLongLongLongLongLongLongString';
+
+ // good
+ const foo = (
+ superLongLongLongLongLongLongLongLongFunctionName()
+ );
+
+ // good
+ const foo = 'superLongLongLongLongLongLongLongLongString';
+ ```
+
+
+ - [13.8](#variables--no-unused-vars) Disallow unused variables. eslint: [`no-unused-vars`](https://eslint.org/docs/rules/no-unused-vars)
+
+ > Why? Variables that are declared and not used anywhere in the code are most likely an error due to incomplete refactoring. Such variables take up space in the code and can lead to confusion by readers.
+
+ ```javascript
+ // bad
+
+ const some_unused_var = 42;
+
+ // Write-only variables are not considered as used.
+ let y = 10;
+ y = 5;
+
+ // A read for a modification of itself is not considered as used.
+ let z = 0;
+ z = z + 1;
+
+ // Unused function arguments.
+ function getX(x, y) {
+ return x;
+ }
+
+ // good
+
+ function getXPlusY(x, y) {
+ return x + y;
+ }
+ const x = 1;
+ const y = a + 2;
+
+ alert(getXPlusY(x, y));
+
+ // 'type' is ignored even if unused because it has a rest property sibling.
+ // This is a form of extracting an object that omits the specified keys.
+ const { type, ...coords } = data;
+ // 'coords' is now the 'data' object without its 'type' property.
+ ```
+
+**[⬆ back to top](#table-of-contents)**
## Hoisting
- - [14.1](#hoisting--about) `var` declarations get hoisted to the top of their scope, their assignment does not. `const` and `let` declarations are blessed with a new concept called [Temporal Dead Zones (TDZ)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let#Temporal_dead_zone_and_errors_with_let). It's important to know why [typeof is no longer safe](http://es-discourse.com/t/why-typeof-is-no-longer-safe/15).
+ - [14.1](#hoisting--about) `var` declarations get hoisted to the top of their closest enclosing function scope, their assignment does not. `const` and `let` declarations are blessed with a new concept called [Temporal Dead Zones (TDZ)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/let#temporal_dead_zone_tdz). It’s important to know why [typeof is no longer safe](https://web.archive.org/web/20200121061528/http://es-discourse.com/t/why-typeof-is-no-longer-safe/15).
```javascript
- // we know this wouldn't work (assuming there
+ // we know this wouldn’t work (assuming there
// is no notDefined global variable)
function example() {
console.log(notDefined); // => throws a ReferenceError
@@ -1634,8 +1923,8 @@ Other Style Guides
}
```
-
- - [14.3](#hoisting--named-expresions) Named function expressions hoist the variable name, not the function name or the function body.
+
+ - [14.3](#hoisting--named-expressions) Named function expressions hoist the variable name, not the function name or the function body.
```javascript
function example() {
@@ -1659,7 +1948,7 @@ Other Style Guides
var named = function named() {
console.log('named');
- }
+ };
}
```
@@ -1676,27 +1965,76 @@ Other Style Guides
}
```
- - For more information refer to [JavaScript Scoping & Hoisting](http://www.adequatelygood.com/2010/2/JavaScript-Scoping-and-Hoisting/) by [Ben Cherry](http://www.adequatelygood.com/).
+
+ - [14.5](#no-use-before-define) Variables, classes, and functions should be defined before they can be used. eslint: [`no-use-before-define`](https://eslint.org/docs/latest/rules/no-use-before-define)
-**[⬆ back to top](#table-of-contents)**
+ > Why? When variables, classes, or functions are declared after being used, it can harm readability since a reader won't know what a thing that's referenced is. It's much clearer for a reader to first encounter the source of a thing (whether imported from another module, or defined in the file) before encountering a use of the thing.
+ ```javascript
+ // bad
-## Comparison Operators & Equality
+ // Variable a is being used before it is being defined.
+ console.log(a); // this will be undefined, since while the declaration is hoisted, the initialization is not
+ var a = 10;
-
- - [15.1](#comparison--eqeqeq) Use `===` and `!==` over `==` and `!=`. eslint: [`eqeqeq`](http://eslint.org/docs/rules/eqeqeq.html)
+ // Function fun is being called before being defined.
+ fun();
+ function fun() {}
-
- - [15.2](#comparison--if) Conditional statements such as the `if` statement evaluate their expression using coercion with the `ToBoolean` abstract method and always follow these simple rules:
+ // Class A is being used before being defined.
+ new A(); // ReferenceError: Cannot access 'A' before initialization
+ class A {
+ }
- + **Objects** evaluate to **true**
- + **Undefined** evaluates to **false**
- + **Null** evaluates to **false**
- + **Booleans** evaluate to **the value of the boolean**
- + **Numbers** evaluate to **false** if **+0, -0, or NaN**, otherwise **true**
- + **Strings** evaluate to **false** if an empty string `''`, otherwise **true**
+ // `let` and `const` are hoisted, but they don't have a default initialization.
+ // The variables 'a' and 'b' are in a Temporal Dead Zone where JavaScript
+ // knows they exist (declaration is hoisted) but they are not accessible
+ // (as they are not yet initialized).
- ```javascript
+ console.log(a); // ReferenceError: Cannot access 'a' before initialization
+ console.log(b); // ReferenceError: Cannot access 'b' before initialization
+ let a = 10;
+ const b = 5;
+
+
+ // good
+
+ var a = 10;
+ console.log(a); // 10
+
+ function fun() {}
+ fun();
+
+ class A {
+ }
+ new A();
+
+ let a = 10;
+ const b = 5;
+ console.log(a); // 10
+ console.log(b); // 5
+ ```
+
+ - For more information refer to [JavaScript Scoping & Hoisting](https://www.adequatelygood.com/2010/2/JavaScript-Scoping-and-Hoisting/) by [Ben Cherry](https://www.adequatelygood.com/).
+
+**[⬆ back to top](#table-of-contents)**
+
+## Comparison Operators & Equality
+
+
+ - [15.1](#comparison--eqeqeq) Use `===` and `!==` over `==` and `!=`. eslint: [`eqeqeq`](https://eslint.org/docs/rules/eqeqeq)
+
+
+ - [15.2](#comparison--if) Conditional statements such as the `if` statement evaluate their expression using coercion with the `ToBoolean` abstract method and always follow these simple rules:
+
+ - **Objects** evaluate to **true**
+ - **Undefined** evaluates to **false**
+ - **Null** evaluates to **false**
+ - **Booleans** evaluate to **the value of the boolean**
+ - **Numbers** evaluate to **false** if **+0, -0, or NaN**, otherwise **true**
+ - **Strings** evaluate to **false** if an empty string `''`, otherwise **true**
+
+ ```javascript
if ([0] && []) {
// true
// an array (even an empty one) is an object, objects will evaluate to true
@@ -1709,44 +2047,42 @@ Other Style Guides
```javascript
// bad
if (isValid === true) {
- // ...stuff...
+ // ...
}
// good
if (isValid) {
- // ...stuff...
+ // ...
}
// bad
if (name) {
- // ...stuff...
+ // ...
}
// good
if (name !== '') {
- // ...stuff...
+ // ...
}
// bad
if (collection.length) {
- // ...stuff...
+ // ...
}
// good
if (collection.length > 0) {
- // ...stuff...
+ // ...
}
```
- - [15.4](#comparison--moreinfo) For more information see [Truth Equality and JavaScript](https://javascriptweblog.wordpress.com/2011/02/07/truth-equality-and-javascript/#more-2108) by Angus Croll.
+ - [15.4](#comparison--moreinfo) For more information see [Truth, Equality, and JavaScript](https://javascriptweblog.wordpress.com/2011/02/07/truth-equality-and-javascript/#more-2108) by Angus Croll.
- - [15.5](#comparison--switch-blocks) Use braces to create blocks in `case` and `default` clauses that contain lexical declarations (e.g. `let`, `const`, `function`, and `class`).
-
- > Why? Lexical declarations are visible in the entire `switch` block but only get initialized when assigned, which only happens when its `case` is reached. This causes problems when multiple `case` clauses attempt to define the same thing.
+ - [15.5](#comparison--switch-blocks) Use braces to create blocks in `case` and `default` clauses that contain lexical declarations (e.g. `let`, `const`, `function`, and `class`). eslint: [`no-case-declarations`](https://eslint.org/docs/rules/no-case-declarations)
- eslint rules: [`no-case-declarations`](http://eslint.org/docs/rules/no-case-declarations.html).
+ > Why? Lexical declarations are visible in the entire `switch` block but only get initialized when assigned, which only happens when its `case` is reached. This causes problems when multiple `case` clauses attempt to define the same thing.
```javascript
// bad
@@ -1758,7 +2094,9 @@ Other Style Guides
const y = 2;
break;
case 3:
- function f() {}
+ function f() {
+ // ...
+ }
break;
default:
class C {}
@@ -1775,7 +2113,9 @@ Other Style Guides
break;
}
case 3: {
- function f() {}
+ function f() {
+ // ...
+ }
break;
}
case 4:
@@ -1788,9 +2128,7 @@ Other Style Guides
```
- - [15.6](#comparison--nested-ternaries) Ternaries should not be nested and generally be single line expressions.
-
- eslint rules: [`no-nested-ternary`](http://eslint.org/docs/rules/no-nested-ternary.html).
+ - [15.6](#comparison--nested-ternaries) Ternaries should not be nested and generally be single line expressions. eslint: [`no-nested-ternary`](https://eslint.org/docs/rules/no-nested-ternary)
```javascript
// bad
@@ -1798,43 +2136,105 @@ Other Style Guides
? "bar"
: value1 > value2 ? "baz" : null;
- // better
+ // split into 2 separated ternary expressions
const maybeNull = value1 > value2 ? 'baz' : null;
+ // better
const foo = maybe1 > maybe2
? 'bar'
: maybeNull;
// best
- const maybeNull = value1 > value2 ? 'baz' : null;
-
const foo = maybe1 > maybe2 ? 'bar' : maybeNull;
```
- - [15.7](#comparison--unneeded-ternary) Avoid unneeded ternary statements.
-
- eslint rules: [`no-unneeded-ternary`](http://eslint.org/docs/rules/no-unneeded-ternary.html).
+ - [15.7](#comparison--unneeded-ternary) Avoid unneeded ternary statements. eslint: [`no-unneeded-ternary`](https://eslint.org/docs/rules/no-unneeded-ternary)
```javascript
// bad
const foo = a ? a : b;
const bar = c ? true : false;
const baz = c ? false : true;
+ const quux = a != null ? a : b;
// good
const foo = a || b;
const bar = !!c;
const baz = !c;
+ const quux = a ?? b;
```
-**[⬆ back to top](#table-of-contents)**
+
+ - [15.8](#comparison--no-mixed-operators) When mixing operators, enclose them in parentheses. The only exception is the standard arithmetic operators: `+`, `-`, and `**` since their precedence is broadly understood. We recommend enclosing `/` and `*` in parentheses because their precedence can be ambiguous when they are mixed.
+ eslint: [`no-mixed-operators`](https://eslint.org/docs/rules/no-mixed-operators)
+ > Why? This improves readability and clarifies the developer’s intention.
+
+ ```javascript
+ // bad
+ const foo = a && b < 0 || c > 0 || d + 1 === 0;
+
+ // bad
+ const bar = a ** b - 5 % d;
+
+ // bad
+ // one may be confused into thinking (a || b) && c
+ if (a || b && c) {
+ return d;
+ }
+
+ // bad
+ const bar = a + b / c * d;
+
+ // good
+ const foo = (a && b < 0) || c > 0 || (d + 1 === 0);
+
+ // good
+ const bar = a ** b - (5 % d);
+
+ // good
+ if (a || (b && c)) {
+ return d;
+ }
+
+ // good
+ const bar = a + (b / c) * d;
+ ```
+
+
+ - [15.9](#nullish-coalescing-operator) The nullish coalescing operator (`??`) is a logical operator that returns its right-hand side operand when its left-hand side operand is `null` or `undefined`. Otherwise, it returns the left-hand side operand.
+
+ > Why? It provides precision by distinguishing null/undefined from other falsy values, enhancing code clarity and predictability.
+
+ ```javascript
+ // bad
+ const value = 0 ?? 'default';
+ // returns 0, not 'default'
+
+ // bad
+ const value = '' ?? 'default';
+ // returns '', not 'default'
+
+ // good
+ const value = null ?? 'default';
+ // returns 'default'
+
+ // good
+ const user = {
+ name: 'John',
+ age: null
+ };
+ const age = user.age ?? 18;
+ // returns 18
+ ```
+
+**[⬆ back to top](#table-of-contents)**
## Blocks
- - [16.1](#blocks--braces) Use braces with all multi-line blocks.
+ - [16.1](#blocks--braces) Use braces with all multiline blocks. eslint: [`nonblock-statement-body-position`](https://eslint.org/docs/rules/nonblock-statement-body-position)
```javascript
// bad
@@ -1859,7 +2259,7 @@ Other Style Guides
```
- - [16.2](#blocks--cuddled-elses) If you're using multi-line blocks with `if` and `else`, put `else` on the same line as your `if` block's closing brace. eslint: [`brace-style`](http://eslint.org/docs/rules/brace-style.html) jscs: [`disallowNewlineBeforeBlockStatements`](http://jscs.info/rule/disallowNewlineBeforeBlockStatements)
+ - [16.2](#blocks--cuddled-elses) If you’re using multiline blocks with `if` and `else`, put `else` on the same line as your `if` block’s closing brace. eslint: [`brace-style`](https://eslint.org/docs/rules/brace-style)
```javascript
// bad
@@ -1880,14 +2280,148 @@ Other Style Guides
}
```
+
+ - [16.3](#blocks--no-else-return) If an `if` block always executes a `return` statement, the subsequent `else` block is unnecessary. A `return` in an `else if` block following an `if` block that contains a `return` can be separated into multiple `if` blocks. eslint: [`no-else-return`](https://eslint.org/docs/rules/no-else-return)
+
+ ```javascript
+ // bad
+ function foo() {
+ if (x) {
+ return x;
+ } else {
+ return y;
+ }
+ }
+
+ // bad
+ function cats() {
+ if (x) {
+ return x;
+ } else if (y) {
+ return y;
+ }
+ }
+
+ // bad
+ function dogs() {
+ if (x) {
+ return x;
+ } else {
+ if (y) {
+ return y;
+ }
+ }
+ }
+
+ // good
+ function foo() {
+ if (x) {
+ return x;
+ }
+
+ return y;
+ }
+
+ // good
+ function cats() {
+ if (x) {
+ return x;
+ }
+
+ if (y) {
+ return y;
+ }
+ }
+
+ // good
+ function dogs(x) {
+ if (x) {
+ if (z) {
+ return y;
+ }
+ } else {
+ return z;
+ }
+ }
+ ```
**[⬆ back to top](#table-of-contents)**
+## Control Statements
+
+
+ - [17.1](#control-statements) In case your control statement (`if`, `while` etc.) gets too long or exceeds the maximum line length, each (grouped) condition could be put into a new line. The logical operator should begin the line.
+
+ > Why? Requiring operators at the beginning of the line keeps the operators aligned and follows a pattern similar to method chaining. This also improves readability by making it easier to visually follow complex logic.
+
+ ```javascript
+ // bad
+ if ((foo === 123 || bar === 'abc') && doesItLookGoodWhenItBecomesThatLong() && isThisReallyHappening()) {
+ thing1();
+ }
+
+ // bad
+ if (foo === 123 &&
+ bar === 'abc') {
+ thing1();
+ }
+
+ // bad
+ if (foo === 123
+ && bar === 'abc') {
+ thing1();
+ }
+
+ // bad
+ if (
+ foo === 123 &&
+ bar === 'abc'
+ ) {
+ thing1();
+ }
+
+ // good
+ if (
+ foo === 123
+ && bar === 'abc'
+ ) {
+ thing1();
+ }
+
+ // good
+ if (
+ (foo === 123 || bar === 'abc')
+ && doesItLookGoodWhenItBecomesThatLong()
+ && isThisReallyHappening()
+ ) {
+ thing1();
+ }
+
+ // good
+ if (foo === 123 && bar === 'abc') {
+ thing1();
+ }
+ ```
+
+
+ - [17.2](#control-statements--value-selection) Don't use selection operators in place of control statements.
+
+ ```javascript
+ // bad
+ !isRunning && startRunning();
+
+ // good
+ if (!isRunning) {
+ startRunning();
+ }
+ ```
+
+**[⬆ back to top](#table-of-contents)**
## Comments
- - [17.1](#comments--multiline) Use `/** ... */` for multi-line comments.
+ - [18.1](#comments--multiline) Use `/** ... */` for multiline comments.
```javascript
// bad
@@ -1898,7 +2432,7 @@ Other Style Guides
// @return {Element} element
function make(tag) {
- // ...stuff...
+ // ...
return element;
}
@@ -1910,14 +2444,14 @@ Other Style Guides
*/
function make(tag) {
- // ...stuff...
+ // ...
return element;
}
```
- - [17.2](#comments--singleline) Use `//` for single line comments. Place single line comments on a newline above the subject of the comment. Put an empty line before the comment unless it's on the first line of a block.
+ - [18.2](#comments--singleline) Use `//` for single line comments. Place single line comments on a newline above the subject of the comment. Put an empty line before the comment unless it’s on the first line of a block.
```javascript
// bad
@@ -1931,7 +2465,7 @@ Other Style Guides
function getType() {
console.log('fetching type...');
// set the default type to 'no type'
- const type = this._type || 'no type';
+ const type = this.type || 'no type';
return type;
}
@@ -1941,7 +2475,7 @@ Other Style Guides
console.log('fetching type...');
// set the default type to 'no type'
- const type = this._type || 'no type';
+ const type = this.type || 'no type';
return type;
}
@@ -1949,13 +2483,14 @@ Other Style Guides
// also good
function getType() {
// set the default type to 'no type'
- const type = this._type || 'no type';
+ const type = this.type || 'no type';
return type;
}
```
- - [17.3](#comments--spaces) Start all comments with a space to make it easier to read. eslint: [`spaced-comment`](http://eslint.org/docs/rules/spaced-comment)
+
+ - [18.3](#comments--spaces) Start all comments with a space to make it easier to read. eslint: [`spaced-comment`](https://eslint.org/docs/rules/spaced-comment)
```javascript
// bad
@@ -1973,7 +2508,7 @@ Other Style Guides
*/
function make(tag) {
- // ...stuff...
+ // ...
return element;
}
@@ -1985,31 +2520,31 @@ Other Style Guides
*/
function make(tag) {
- // ...stuff...
+ // ...
return element;
}
```
- - [17.4](#comments--actionitems) Prefixing your comments with `FIXME` or `TODO` helps other developers quickly understand if you're pointing out a problem that needs to be revisited, or if you're suggesting a solution to the problem that needs to be implemented. These are different than regular comments because they are actionable. The actions are `FIXME: -- need to figure this out` or `TODO: -- need to implement`.
+ - [18.4](#comments--actionitems) Prefixing your comments with `FIXME` or `TODO` helps other developers quickly understand if you’re pointing out a problem that needs to be revisited, or if you’re suggesting a solution to the problem that needs to be implemented. These are different than regular comments because they are actionable. The actions are `FIXME: -- need to figure this out` or `TODO: -- need to implement`.
- - [17.5](#comments--fixme) Use `// FIXME:` to annotate problems.
+ - [18.5](#comments--fixme) Use `// FIXME:` to annotate problems.
```javascript
class Calculator extends Abacus {
constructor() {
super();
- // FIXME: shouldn't use a global here
+ // FIXME: shouldn’t use a global here
total = 0;
}
}
```
- - [17.6](#comments--todo) Use `// TODO:` to annotate solutions to problems.
+ - [18.6](#comments--todo) Use `// TODO:` to annotate solutions to problems.
```javascript
class Calculator extends Abacus {
@@ -2024,31 +2559,30 @@ Other Style Guides
**[⬆ back to top](#table-of-contents)**
-
## Whitespace
- - [18.1](#whitespace--spaces) Use soft tabs set to 2 spaces. eslint: [`indent`](http://eslint.org/docs/rules/indent.html) jscs: [`validateIndentation`](http://jscs.info/rule/validateIndentation)
+ - [19.1](#whitespace--spaces) Use soft tabs (space character) set to 2 spaces. eslint: [`indent`](https://eslint.org/docs/rules/indent)
```javascript
// bad
function foo() {
- ∙∙∙∙const name;
+ ∙∙∙∙let name;
}
// bad
function bar() {
- ∙const name;
+ ∙let name;
}
// good
function baz() {
- ∙∙const name;
+ ∙∙let name;
}
```
- - [18.2](#whitespace--before-blocks) Place 1 space before the leading brace. eslint: [`space-before-blocks`](http://eslint.org/docs/rules/space-before-blocks.html) jscs: [`requireSpaceBeforeBlockStatements`](http://jscs.info/rule/requireSpaceBeforeBlockStatements)
+ - [19.2](#whitespace--before-blocks) Place 1 space before the leading brace. eslint: [`space-before-blocks`](https://eslint.org/docs/rules/space-before-blocks)
```javascript
// bad
@@ -2075,7 +2609,7 @@ Other Style Guides
```
- - [18.3](#whitespace--around-keywords) Place 1 space before the opening parenthesis in control statements (`if`, `while` etc.). Place no space between the argument list and the function name in function calls and declarations. eslint: [`keyword-spacing`](http://eslint.org/docs/rules/keyword-spacing.html) jscs: [`requireSpaceAfterKeywords`](http://jscs.info/rule/requireSpaceAfterKeywords)
+ - [19.3](#whitespace--around-keywords) Place 1 space before the opening parenthesis in control statements (`if`, `while` etc.). Place no space between the argument list and the function name in function calls and declarations. eslint: [`keyword-spacing`](https://eslint.org/docs/rules/keyword-spacing)
```javascript
// bad
@@ -2100,7 +2634,7 @@ Other Style Guides
```
- - [18.4](#whitespace--infix-ops) Set off operators with spaces. eslint: [`space-infix-ops`](http://eslint.org/docs/rules/space-infix-ops.html) jscs: [`requireSpaceBeforeBinaryOperators`](http://jscs.info/rule/requireSpaceBeforeBinaryOperators), [`requireSpaceAfterBinaryOperators`](http://jscs.info/rule/requireSpaceAfterBinaryOperators)
+ - [19.4](#whitespace--infix-ops) Set off operators with spaces. eslint: [`space-infix-ops`](https://eslint.org/docs/rules/space-infix-ops)
```javascript
// bad
@@ -2111,33 +2645,33 @@ Other Style Guides
```
- - [18.5](#whitespace--newline-at-end) End files with a single newline character. eslint: [`eol-last`](https://github.com/eslint/eslint/blob/master/docs/rules/eol-last.md)
+ - [19.5](#whitespace--newline-at-end) End files with a single newline character. eslint: [`eol-last`](https://eslint.org/docs/rules/eol-last)
```javascript
// bad
- (function (global) {
- // ...stuff...
- })(this);
+ import { es6 } from './AirbnbStyleGuide';
+ // ...
+ export default es6;
```
```javascript
// bad
- (function (global) {
- // ...stuff...
- })(this);↵
+ import { es6 } from './AirbnbStyleGuide';
+ // ...
+ export default es6;↵
↵
```
```javascript
// good
- (function (global) {
- // ...stuff...
- })(this);↵
+ import { es6 } from './AirbnbStyleGuide';
+ // ...
+ export default es6;↵
```
- - [18.6](#whitespace--chains) Use indentation when making long method chains (more than 2 method chains). Use a leading dot, which
- emphasizes that the line is a method call, not a new statement. eslint: [`newline-per-chained-call`](http://eslint.org/docs/rules/newline-per-chained-call) [`no-whitespace-before-property`](http://eslint.org/docs/rules/no-whitespace-before-property)
+ - [19.6](#whitespace--chains) Use indentation when making long method chains (more than 2 method chains). Use a leading dot, which
+ emphasizes that the line is a method call, not a new statement. eslint: [`newline-per-chained-call`](https://eslint.org/docs/rules/newline-per-chained-call) [`no-whitespace-before-property`](https://eslint.org/docs/rules/no-whitespace-before-property)
```javascript
// bad
@@ -2162,7 +2696,7 @@ Other Style Guides
// bad
const leds = stage.selectAll('.led').data(data).enter().append('svg:svg').classed('led', true)
.attr('width', (radius + margin) * 2).append('svg:g')
- .attr('transform', 'translate(' + (radius + margin) + ',' + (radius + margin) + ')')
+ .attr('transform', `translate(${radius + margin}, ${radius + margin})`)
.call(tron.led);
// good
@@ -2172,15 +2706,19 @@ Other Style Guides
.classed('led', true)
.attr('width', (radius + margin) * 2)
.append('svg:g')
- .attr('transform', 'translate(' + (radius + margin) + ',' + (radius + margin) + ')')
+ .attr('transform', `translate(${radius + margin}, ${radius + margin})`)
.call(tron.led);
// good
const leds = stage.selectAll('.led').data(data);
+ const svg = leds.enter().append('svg:svg');
+ svg.classed('led', true).attr('width', (radius + margin) * 2);
+ const g = svg.append('svg:g');
+ g.attr('transform', `translate(${radius + margin}, ${radius + margin})`).call(tron.led);
```
- - [18.7](#whitespace--after-blocks) Leave a blank line after blocks and before the next statement. jscs: [`requirePaddingNewLinesAfterBlocks`](http://jscs.info/rule/requirePaddingNewLinesAfterBlocks)
+ - [19.7](#whitespace--after-blocks) Leave a blank line after blocks and before the next statement.
```javascript
// bad
@@ -2238,7 +2776,7 @@ Other Style Guides
```
- - [18.8](#whitespace--padded-blocks) Do not pad your blocks with blank lines. eslint: [`padded-blocks`](http://eslint.org/docs/rules/padded-blocks.html) jscs: [`disallowPaddingNewlinesInBlocks`](http://jscs.info/rule/disallowPaddingNewlinesInBlocks)
+ - [19.8](#whitespace--padded-blocks) Do not pad your blocks with blank lines. eslint: [`padded-blocks`](https://eslint.org/docs/rules/padded-blocks)
```javascript
// bad
@@ -2248,15 +2786,23 @@ Other Style Guides
}
- // also bad
+ // bad
if (baz) {
- console.log(qux);
+ console.log(quux);
} else {
console.log(foo);
}
+ // bad
+ class Foo {
+
+ constructor(bar) {
+ this.bar = bar;
+ }
+ }
+
// good
function bar() {
console.log(foo);
@@ -2264,14 +2810,68 @@ Other Style Guides
// good
if (baz) {
- console.log(qux);
+ console.log(quux);
} else {
console.log(foo);
}
```
+
+ - [19.9](#whitespace--no-multiple-blanks) Do not use multiple blank lines to pad your code. eslint: [`no-multiple-empty-lines`](https://eslint.org/docs/rules/no-multiple-empty-lines)
+
+
+ ```javascript
+ // bad
+ class Person {
+ constructor(fullName, email, birthday) {
+ this.fullName = fullName;
+
+
+ this.email = email;
+
+
+ this.setAge(birthday);
+ }
+
+
+ setAge(birthday) {
+ const today = new Date();
+
+
+ const age = this.getAge(today, birthday);
+
+
+ this.age = age;
+ }
+
+
+ getAge(today, birthday) {
+ // ..
+ }
+ }
+
+ // good
+ class Person {
+ constructor(fullName, email, birthday) {
+ this.fullName = fullName;
+ this.email = email;
+ this.setAge(birthday);
+ }
+
+ setAge(birthday) {
+ const today = new Date();
+ const age = getAge(today, birthday);
+ this.age = age;
+ }
+
+ getAge(today, birthday) {
+ // ..
+ }
+ }
+ ```
+
- - [18.9](#whitespace--in-parens) Do not add spaces inside parentheses. eslint: [`space-in-parens`](http://eslint.org/docs/rules/space-in-parens.html) jscs: [`disallowSpacesInsideParentheses`](http://jscs.info/rule/disallowSpacesInsideParentheses)
+ - [19.10](#whitespace--in-parens) Do not add spaces inside parentheses. eslint: [`space-in-parens`](https://eslint.org/docs/rules/space-in-parens)
```javascript
// bad
@@ -2296,7 +2896,7 @@ Other Style Guides
```
- - [18.10](#whitespace--in-brackets) Do not add spaces inside brackets. eslint: [`array-bracket-spacing`](http://eslint.org/docs/rules/array-bracket-spacing.html) jscs: [`disallowSpacesInsideArrayBrackets`](http://jscs.info/rule/disallowSpacesInsideArrayBrackets)
+ - [19.11](#whitespace--in-brackets) Do not add spaces inside brackets. eslint: [`array-bracket-spacing`](https://eslint.org/docs/rules/array-bracket-spacing)
```javascript
// bad
@@ -2309,7 +2909,7 @@ Other Style Guides
```
- - [18.11](#whitespace--in-braces) Add spaces inside curly braces. eslint: [`object-curly-spacing`](http://eslint.org/docs/rules/object-curly-spacing.html) jscs: [`requireSpacesInsideObjectBrackets`](http://jscs.info/rule/requireSpacesInsideObjectBrackets)
+ - [19.12](#whitespace--in-braces) Add spaces inside curly braces. eslint: [`object-curly-spacing`](https://eslint.org/docs/rules/object-curly-spacing)
```javascript
// bad
@@ -2320,7 +2920,7 @@ Other Style Guides
```
- - [18.12](#whitespace--max-len) Avoid having lines of code that are longer than 100 characters (including whitespace). Note: per [above](#strings--line-length), long strings are exempt from this rule, and should not be broken up. eslint: [`max-len`](http://eslint.org/docs/rules/max-len.html) jscs: [`maximumLineLength`](http://jscs.info/rule/maximumLineLength)
+ - [19.13](#whitespace--max-len) Avoid having lines of code that are longer than 100 characters (including whitespace). Note: per [above](#strings--line-length), long strings are exempt from this rule, and should not be broken up. eslint: [`max-len`](https://eslint.org/docs/rules/max-len)
> Why? This ensures readability and maintainability.
@@ -2339,6 +2939,14 @@ Other Style Guides
&& jsonData.foo.bar.baz.quux
&& jsonData.foo.bar.baz.quux.xyzzy;
+ // better
+ const foo = jsonData
+ ?.foo
+ ?.bar
+ ?.baz
+ ?.quux
+ ?.xyzzy;
+
// good
$.ajax({
method: 'POST',
@@ -2349,12 +2957,112 @@ Other Style Guides
.fail(() => console.log('You have failed this city.'));
```
+
+ - [19.14](#whitespace--block-spacing) Require consistent spacing inside an open block token and the next token on the same line. This rule also enforces consistent spacing inside a close block token and previous token on the same line. eslint: [`block-spacing`](https://eslint.org/docs/rules/block-spacing)
+
+ ```javascript
+ // bad
+ function foo() {return true;}
+ if (foo) { bar = 0;}
+
+ // good
+ function foo() { return true; }
+ if (foo) { bar = 0; }
+ ```
+
+
+ - [19.15](#whitespace--comma-spacing) Avoid spaces before commas and require a space after commas. eslint: [`comma-spacing`](https://eslint.org/docs/rules/comma-spacing)
+
+ ```javascript
+ // bad
+ const foo = 1,bar = 2;
+ const arr = [1 , 2];
+
+ // good
+ const foo = 1, bar = 2;
+ const arr = [1, 2];
+ ```
+
+
+ - [19.16](#whitespace--computed-property-spacing) Enforce spacing inside of computed property brackets. eslint: [`computed-property-spacing`](https://eslint.org/docs/rules/computed-property-spacing)
+
+ ```javascript
+ // bad
+ obj[foo ]
+ obj[ 'foo']
+ const x = {[ b ]: a}
+ obj[foo[ bar ]]
+
+ // good
+ obj[foo]
+ obj['foo']
+ const x = { [b]: a }
+ obj[foo[bar]]
+ ```
+
+
+ - [19.17](#whitespace--func-call-spacing) Avoid spaces between functions and their invocations. eslint: [`func-call-spacing`](https://eslint.org/docs/rules/func-call-spacing)
+
+ ```javascript
+ // bad
+ func ();
+
+ func
+ ();
+
+ // good
+ func();
+ ```
+
+
+ - [19.18](#whitespace--key-spacing) Enforce spacing between keys and values in object literal properties. eslint: [`key-spacing`](https://eslint.org/docs/rules/key-spacing)
+
+ ```javascript
+ // bad
+ const obj = { foo : 42 };
+ const obj2 = { foo:42 };
+
+ // good
+ const obj = { foo: 42 };
+ ```
+
+
+ - [19.19](#whitespace--no-trailing-spaces) Avoid trailing spaces at the end of lines. eslint: [`no-trailing-spaces`](https://eslint.org/docs/rules/no-trailing-spaces)
+
+
+ - [19.20](#whitespace--no-multiple-empty-lines) Avoid multiple empty lines, only allow one newline at the end of files, and avoid a newline at the beginning of files. eslint: [`no-multiple-empty-lines`](https://eslint.org/docs/rules/no-multiple-empty-lines)
+
+
+ ```javascript
+ // bad - multiple empty lines
+ const x = 1;
+
+
+ const y = 2;
+
+ // bad - 2+ newlines at end of file
+ const x = 1;
+ const y = 2;
+
+
+ // bad - 1+ newline(s) at beginning of file
+
+ const x = 1;
+ const y = 2;
+
+ // good
+ const x = 1;
+ const y = 2;
+
+ ```
+
+
**[⬆ back to top](#table-of-contents)**
## Commas
-
- - [19.1](#commas--leading-trailing) Leading commas: **Nope.** eslint: [`comma-style`](http://eslint.org/docs/rules/comma-style.html) jscs: [`requireCommaBeforeLineBreak`](http://jscs.info/rule/requireCommaBeforeLineBreak)
+
+ - [20.1](#commas--leading-trailing) Leading commas: **Nope.** eslint: [`comma-style`](https://eslint.org/docs/rules/comma-style)
```javascript
// bad
@@ -2389,11 +3097,11 @@ Other Style Guides
```
- - [19.2](#commas--dangling) Additional trailing comma: **Yup.** eslint: [`comma-dangle`](http://eslint.org/docs/rules/comma-dangle.html) jscs: [`requireTrailingComma`](http://jscs.info/rule/requireTrailingComma)
+ - [20.2](#commas--dangling) Additional trailing comma: **Yup.** eslint: [`comma-dangle`](https://eslint.org/docs/rules/comma-dangle)
- > Why? This leads to cleaner git diffs. Also, transpilers like Babel will remove the additional trailing comma in the transpiled code which means you don't have to worry about the [trailing comma problem](https://github.com/airbnb/javascript/blob/es5-deprecated/es5/README.md#commas) in legacy browsers.
+ > Why? This leads to cleaner git diffs. Also, transpilers like Babel will remove the additional trailing comma in the transpiled code which means you don’t have to worry about the [trailing comma problem](https://github.com/airbnb/javascript/blob/es5-deprecated/es5/README.md#commas) in legacy browsers.
- ```javascript
+ ```diff
// bad - git diff without trailing comma
const hero = {
firstName: 'Florence',
@@ -2408,7 +3116,9 @@ Other Style Guides
lastName: 'Nightingale',
+ inventorOf: ['coxcomb chart', 'modern nursing'],
};
+ ```
+ ```javascript
// bad
const hero = {
firstName: 'Dana',
@@ -2479,65 +3189,89 @@ Other Style Guides
lastName,
inventorOf,
...heroArgs
- )
+ );
```
**[⬆ back to top](#table-of-contents)**
-
## Semicolons
- - [20.1](#20.1) **Yup.** eslint: [`semi`](http://eslint.org/docs/rules/semi.html) jscs: [`requireSemicolons`](http://jscs.info/rule/requireSemicolons)
+ - [21.1](#semicolons--required) **Yup.** eslint: [`semi`](https://eslint.org/docs/rules/semi)
+
+ > Why? When JavaScript encounters a line break without a semicolon, it uses a set of rules called [Automatic Semicolon Insertion](https://tc39.github.io/ecma262/#sec-automatic-semicolon-insertion) to determine whether it should regard that line break as the end of a statement, and (as the name implies) place a semicolon into your code before the line break if it thinks so. ASI contains a few eccentric behaviors, though, and your code will break if JavaScript misinterprets your line break. These rules will become more complicated as new features become a part of JavaScript. Explicitly terminating your statements and configuring your linter to catch missing semicolons will help prevent you from encountering issues.
```javascript
- // bad
- (function () {
- const name = 'Skywalker'
- return name
- })()
+ // bad - raises exception
+ const luke = {}
+ const leia = {}
+ [luke, leia].forEach((jedi) => jedi.father = 'vader')
+
+ // bad - raises exception
+ const reaction = "No! That’s impossible!"
+ (async function meanwhileOnTheFalcon() {
+ // handle `leia`, `lando`, `chewie`, `r2`, `c3p0`
+ // ...
+ }())
+
+ // bad - returns `undefined` instead of the value on the next line - always happens when `return` is on a line by itself because of ASI!
+ function foo() {
+ return
+ 'search your feelings, you know it to be foo'
+ }
// good
- (function () {
- const name = 'Skywalker';
- return name;
- }());
+ const luke = {};
+ const leia = {};
+ [luke, leia].forEach((jedi) => {
+ jedi.father = 'vader';
+ });
- // good, but legacy (guards against the function becoming an argument when two files with IIFEs are concatenated)
- ;(() => {
- const name = 'Skywalker';
- return name;
+ // good
+ const reaction = 'No! That’s impossible!';
+ (async function meanwhileOnTheFalcon() {
+ // handle `leia`, `lando`, `chewie`, `r2`, `c3p0`
+ // ...
}());
+
+ // good
+ function foo() {
+ return 'search your feelings, you know it to be foo';
+ }
```
- [Read more](https://stackoverflow.com/questions/7365172/semicolon-before-self-invoking-function/7365214%237365214).
+ [Read more](https://stackoverflow.com/questions/7365172/semicolon-before-self-invoking-function/7365214#7365214).
**[⬆ back to top](#table-of-contents)**
-
## Type Casting & Coercion
- - [21.1](#coercion--explicit) Perform type coercion at the beginning of the statement.
+ - [22.1](#coercion--explicit) Perform type coercion at the beginning of the statement.
- - [21.2](#coercion--strings) Strings:
+ - [22.2](#coercion--strings) Strings: eslint: [`no-new-wrappers`](https://eslint.org/docs/rules/no-new-wrappers)
```javascript
// => this.reviewScore = 9;
+ // bad
+ const totalScore = new String(this.reviewScore); // typeof totalScore is "object" not "string"
+
// bad
const totalScore = this.reviewScore + ''; // invokes this.reviewScore.valueOf()
// bad
- const totalScore = this.reviewScore.toString(); // isn't guaranteed to return a string
+ const totalScore = this.reviewScore.toString(); // isn’t guaranteed to return a string
// good
const totalScore = String(this.reviewScore);
```
- - [21.3](#coercion--numbers) Numbers: Use `Number` for type casting and `parseInt` always with a radix for parsing strings. eslint: [`radix`](http://eslint.org/docs/rules/radix)
+ - [22.3](#coercion--numbers) Numbers: Use `Number` for type casting and `parseInt` always with a radix for parsing strings. eslint: [`radix`](https://eslint.org/docs/rules/radix) [`no-new-wrappers`](https://eslint.org/docs/rules/no-new-wrappers)
+
+ > Why? The `parseInt` function produces an integer value dictated by interpretation of the contents of the string argument according to the specified radix. Leading whitespace in string is ignored. If radix is `undefined` or `0`, it is assumed to be `10` except when the number begins with the character pairs `0x` or `0X`, in which case a radix of 16 is assumed. This differs from ECMAScript 3, which merely discouraged (but allowed) octal interpretation. Many implementations have not adopted this behavior as of 2013. And, because older browsers must be supported, always specify a radix.
```javascript
const inputValue = '4';
@@ -2562,7 +3296,7 @@ Other Style Guides
```
- - [21.4](#coercion--comment-deviations) If for whatever reason you are doing something wild and `parseInt` is your bottleneck and need to use Bitshift for [performance reasons](https://jsperf.com/coercion-vs-casting/3), leave a comment explaining why and what you're doing.
+ - [22.4](#coercion--comment-deviations) If for whatever reason you are doing something wild and `parseInt` is your bottleneck and need to use Bitshift for [performance reasons](https://web.archive.org/web/20200414205431/https://jsperf.com/coercion-vs-casting/3), leave a comment explaining why and what you’re doing.
```javascript
// good
@@ -2575,16 +3309,16 @@ Other Style Guides
```
- - [21.5](#coercion--bitwise) **Note:** Be careful when using bitshift operations. Numbers are represented as [64-bit values](https://es5.github.io/#x4.3.19), but bitshift operations always return a 32-bit integer ([source](https://es5.github.io/#x11.7)). Bitshift can lead to unexpected behavior for integer values larger than 32 bits. [Discussion](https://github.com/airbnb/javascript/issues/109). Largest signed 32-bit Int is 2,147,483,647:
+ - [22.5](#coercion--bitwise) **Note:** Be careful when using bitshift operations. Numbers are represented as [64-bit values](https://es5.github.io/#x4.3.19), but bitshift operations always return a 32-bit integer ([source](https://es5.github.io/#x11.7)). Bitshift can lead to unexpected behavior for integer values larger than 32 bits. [Discussion](https://github.com/airbnb/javascript/issues/109). Largest signed 32-bit Int is 2,147,483,647:
```javascript
- 2147483647 >> 0 //=> 2147483647
- 2147483648 >> 0 //=> -2147483648
- 2147483649 >> 0 //=> -2147483647
+ 2147483647 >> 0; // => 2147483647
+ 2147483648 >> 0; // => -2147483648
+ 2147483649 >> 0; // => -2147483647
```
- - [21.6](#coercion--booleans) Booleans:
+ - [22.6](#coercion--booleans) Booleans: eslint: [`no-new-wrappers`](https://eslint.org/docs/rules/no-new-wrappers)
```javascript
const age = 0;
@@ -2601,26 +3335,25 @@ Other Style Guides
**[⬆ back to top](#table-of-contents)**
-
## Naming Conventions
- - [22.1](#naming--descriptive) Avoid single letter names. Be descriptive with your naming. eslint: [`id-length`](http://eslint.org/docs/rules/id-length)
+ - [23.1](#naming--descriptive) Avoid single letter names. Be descriptive with your naming. eslint: [`id-length`](https://eslint.org/docs/rules/id-length)
```javascript
// bad
function q() {
- // ...stuff...
+ // ...
}
// good
function query() {
- // ..stuff..
+ // ...
}
```
- - [22.2](#naming--camelCase) Use camelCase when naming objects, functions, and instances. eslint: [`camelcase`](http://eslint.org/docs/rules/camelcase.html) jscs: [`requireCamelCaseOrUpperCaseIdentifiers`](http://jscs.info/rule/requireCamelCaseOrUpperCaseIdentifiers)
+ - [23.2](#naming--camelCase) Use camelCase when naming objects, functions, and instances. eslint: [`camelcase`](https://eslint.org/docs/rules/camelcase)
```javascript
// bad
@@ -2634,7 +3367,7 @@ Other Style Guides
```
- - [22.3](#naming--PascalCase) Use PascalCase only when naming constructors or classes. eslint: [`new-cap`](http://eslint.org/docs/rules/new-cap.html) jscs: [`requireCapitalizedConstructors`](http://jscs.info/rule/requireCapitalizedConstructors)
+ - [23.3](#naming--PascalCase) Use PascalCase only when naming constructors or classes. eslint: [`new-cap`](https://eslint.org/docs/rules/new-cap)
```javascript
// bad
@@ -2659,9 +3392,9 @@ Other Style Guides
```
- - [22.4](#naming--leading-underscore) Do not use trailing or leading underscores. eslint: [`no-underscore-dangle`](http://eslint.org/docs/rules/no-underscore-dangle.html) jscs: [`disallowDanglingUnderscores`](http://jscs.info/rule/disallowDanglingUnderscores)
+ - [23.4](#naming--leading-underscore) Do not use trailing or leading underscores. eslint: [`no-underscore-dangle`](https://eslint.org/docs/rules/no-underscore-dangle)
- > Why? JavaScript does not have the concept of privacy in terms of properties or methods. Although a leading underscore is a common convention to mean “private”, in fact, these properties are fully public, and as such, are part of your public API contract. This convention might lead developers to wrongly think that a change won't count as breaking, or that tests aren't needed. tl;dr: if you want something to be “private”, it must not be observably present.
+ > Why? JavaScript does not have the concept of privacy in terms of properties or methods. Although a leading underscore is a common convention to mean “private”, in fact, these properties are fully public, and as such, are part of your public API contract. This convention might lead developers to wrongly think that a change won’t count as breaking, or that tests aren’t needed. tl;dr: if you want something to be “private”, it must not be observably present.
```javascript
// bad
@@ -2671,10 +3404,15 @@ Other Style Guides
// good
this.firstName = 'Panda';
+
+ // good, in environments where WeakMaps are available
+ // see https://compat-table.github.io/compat-table/es6/#test-WeakMap
+ const firstNames = new WeakMap();
+ firstNames.set(this, 'Panda');
```
- - [22.5](#naming--self-this) Don't save references to `this`. Use arrow functions or [Function#bind](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind). jscs: [`disallowNodeTypes`](http://jscs.info/rule/disallowNodeTypes)
+ - [23.5](#naming--self-this) Don’t save references to `this`. Use arrow functions or [Function#bind](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind).
```javascript
// bad
@@ -2702,7 +3440,7 @@ Other Style Guides
```
- - [22.6](#naming--filename-matches-export) A base filename should exactly match the name of its default export.
+ - [23.6](#naming--filename-matches-export) A base filename should exactly match the name of its default export.
```javascript
// file 1 contents
@@ -2738,38 +3476,111 @@ Other Style Guides
```
- - [22.7](#naming--camelCase-default-export) Use camelCase when you export-default a function. Your filename should be identical to your function's name.
+ - [23.7](#naming--camelCase-default-export) Use camelCase when you export-default a function. Your filename should be identical to your function’s name.
```javascript
function makeStyleGuide() {
+ // ...
}
export default makeStyleGuide;
```
- - [22.8](#naming--PascalCase-singleton) Use PascalCase when you export a constructor / class / singleton / function library / bare object.
+ - [23.8](#naming--PascalCase-singleton) Use PascalCase when you export a constructor / class / singleton / function library / bare object.
```javascript
const AirbnbStyleGuide = {
es6: {
- }
+ },
};
export default AirbnbStyleGuide;
```
+
+ - [23.9](#naming--Acronyms-and-Initialisms) Acronyms and initialisms should always be all uppercased, or all lowercased.
-**[⬆ back to top](#table-of-contents)**
+ > Why? Names are for readability, not to appease a computer algorithm.
+
+ ```javascript
+ // bad
+ import SmsContainer from './containers/SmsContainer';
+
+ // bad
+ const HttpRequests = [
+ // ...
+ ];
+
+ // good
+ import SMSContainer from './containers/SMSContainer';
+
+ // good
+ const HTTPRequests = [
+ // ...
+ ];
+
+ // also good
+ const httpRequests = [
+ // ...
+ ];
+ // best
+ import TextMessageContainer from './containers/TextMessageContainer';
+
+ // best
+ const requests = [
+ // ...
+ ];
+ ```
+
+
+ - [23.10](#naming--uppercase) You may optionally uppercase a constant only if it (1) is exported, (2) is a `const` (it can not be reassigned), and (3) the programmer can trust it (and its nested properties) to never change.
+
+ > Why? This is an additional tool to assist in situations where the programmer would be unsure if a variable might ever change. UPPERCASE_VARIABLES are letting the programmer know that they can trust the variable (and its properties) not to change.
+ - What about all `const` variables? - This is unnecessary, so uppercasing should not be used for constants within a file. It should be used for exported constants however.
+ - What about exported objects? - Uppercase at the top level of export (e.g. `EXPORTED_OBJECT.key`) and maintain that all nested properties do not change.
+
+ ```javascript
+ // bad
+ const PRIVATE_VARIABLE = 'should not be unnecessarily uppercased within a file';
+
+ // bad
+ export const THING_TO_BE_CHANGED = 'should obviously not be uppercased';
+
+ // bad
+ export let REASSIGNABLE_VARIABLE = 'do not use let with uppercase variables';
+
+ // ---
+
+ // allowed but does not supply semantic value
+ export const apiKey = 'SOMEKEY';
+
+ // better in most cases
+ export const API_KEY = 'SOMEKEY';
+
+ // ---
+
+ // bad - unnecessarily uppercases key while adding no semantic value
+ export const MAPPING = {
+ KEY: 'value'
+ };
+
+ // good
+ export const MAPPING = {
+ key: 'value',
+ };
+ ```
+
+**[⬆ back to top](#table-of-contents)**
## Accessors
- - [23.1](#accessors--not-required) Accessor functions for properties are not required.
+ - [24.1](#accessors--not-required) Accessor functions for properties are not required.
- - [23.2](#accessors--no-getters-setters) Do not use JavaScript getters/setters as they cause unexpected side effects and are harder to test, maintain, and reason about. Instead, if you do make accessor functions, use getVal() and setVal('hello').
+ - [24.2](#accessors--no-getters-setters) Do not use JavaScript getters/setters as they cause unexpected side effects and are harder to test, maintain, and reason about. Instead, if you do make accessor functions, use `getVal()` and `setVal('hello')`.
```javascript
// bad
@@ -2796,7 +3607,7 @@ Other Style Guides
```
- - [23.3](#accessors--boolean-prefix) If the property/method is a `boolean`, use `isVal()` or `hasVal()`.
+ - [24.3](#accessors--boolean-prefix) If the property/method is a `boolean`, use `isVal()` or `hasVal()`.
```javascript
// bad
@@ -2811,7 +3622,7 @@ Other Style Guides
```
- - [23.4](#accessors--consistent) It's okay to create get() and set() functions, but be consistent.
+ - [24.4](#accessors--consistent) It’s okay to create `get()` and `set()` functions, but be consistent.
```javascript
class Jedi {
@@ -2832,20 +3643,19 @@ Other Style Guides
**[⬆ back to top](#table-of-contents)**
-
## Events
- - [24.1](#events--hash) When attaching data payloads to events (whether DOM events or something more proprietary like Backbone events), pass a hash instead of a raw value. This allows a subsequent contributor to add more data to the event payload without finding and updating every handler for the event. For example, instead of:
+ - [25.1](#events--hash) When attaching data payloads to events (whether DOM events or something more proprietary like Backbone events), pass an object literal (also known as a "hash") instead of a raw value. This allows a subsequent contributor to add more data to the event payload without finding and updating every handler for the event. For example, instead of:
```javascript
// bad
$(this).trigger('listingUpdated', listing.id);
- ...
+ // ...
- $(this).on('listingUpdated', (e, listingId) => {
- // do something with listingId
+ $(this).on('listingUpdated', (e, listingID) => {
+ // do something with listingID
});
```
@@ -2853,22 +3663,21 @@ Other Style Guides
```javascript
// good
- $(this).trigger('listingUpdated', { listingId: listing.id });
+ $(this).trigger('listingUpdated', { listingID: listing.id });
- ...
+ // ...
$(this).on('listingUpdated', (e, data) => {
- // do something with data.listingId
+ // do something with data.listingID
});
```
**[⬆ back to top](#table-of-contents)**
-
## jQuery
- - [25.1](#jquery--dollar-prefix) Prefix jQuery object variables with a `$`. jscs: [`requireDollarBeforejQueryAssignment`](http://jscs.info/rule/requireDollarBeforejQueryAssignment)
+ - [26.1](#jquery--dollar-prefix) Prefix jQuery object variables with a `$`.
```javascript
// bad
@@ -2882,17 +3691,17 @@ Other Style Guides
```
- - [25.2](#jquery--cache) Cache jQuery lookups.
+ - [26.2](#jquery--cache) Cache jQuery lookups.
```javascript
// bad
function setSidebar() {
$('.sidebar').hide();
- // ...stuff...
+ // ...
$('.sidebar').css({
- 'background-color': 'pink'
+ 'background-color': 'pink',
});
}
@@ -2901,19 +3710,19 @@ Other Style Guides
const $sidebar = $('.sidebar');
$sidebar.hide();
- // ...stuff...
+ // ...
$sidebar.css({
- 'background-color': 'pink'
+ 'background-color': 'pink',
});
}
```
- - [25.3](#jquery--queries) For DOM queries use Cascading `$('.sidebar ul')` or parent > child `$('.sidebar > ul')`. [jsPerf](http://jsperf.com/jquery-find-vs-context-sel/16)
+ - [26.3](#jquery--queries) For DOM queries use Cascading `$('.sidebar ul')` or parent > child `$('.sidebar > ul')`. [jsPerf](https://web.archive.org/web/20200414183810/https://jsperf.com/jquery-find-vs-context-sel/16)
- - [25.4](#jquery--find) Use `find` with scoped jQuery object queries.
+ - [26.4](#jquery--find) Use `find` with scoped jQuery object queries.
```javascript
// bad
@@ -2934,11 +3743,10 @@ Other Style Guides
**[⬆ back to top](#table-of-contents)**
-
## ECMAScript 5 Compatibility
- - [26.1](#es5-compat--kangax) Refer to [Kangax](https://twitter.com/kangax/)'s ES5 [compatibility table](https://kangax.github.io/es5-compat-table/).
+ - [27.1](#es5-compat--kangax) Refer to [Kangax](https://twitter.com/kangax/)’s ES5 [compatibility table](https://compat-table.github.io/compat-table/es5/).
**[⬆ back to top](#table-of-contents)**
@@ -2946,7 +3754,7 @@ Other Style Guides
## ECMAScript 6+ (ES 2015+) Styles
- - [27.1](#es6-styles) This is a collection of links to the various ES6 features.
+ - [28.1](#es6-styles) This is a collection of links to the various ES6+ features.
1. [Arrow Functions](#arrow-functions)
1. [Classes](#classes--constructors)
@@ -2959,20 +3767,61 @@ Other Style Guides
1. [Rest](#es6-rest)
1. [Array Spreads](#es6-array-spreads)
1. [Let and Const](#references)
+1. [Exponentiation Operator](#es2016-properties--exponentiation-operator)
1. [Iterators and Generators](#iterators-and-generators)
1. [Modules](#modules)
- - [27.2](#tc39-proposals) Do not use [TC39 proposals](https://github.com/tc39/proposals) that have not reached stage 3.
+ - [28.2](#tc39-proposals) Do not use [TC39 proposals](https://github.com/tc39/proposals) that have not reached stage 3.
> Why? [They are not finalized](https://tc39.github.io/process-document/), and they are subject to change or to be withdrawn entirely. We want to use JavaScript, and proposals are not JavaScript yet.
**[⬆ back to top](#table-of-contents)**
+## Standard Library
+
+ The [Standard Library](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects)
+ contains utilities that are functionally broken but remain for legacy reasons.
+
+
+ - [29.1](#standard-library--isnan) Use `Number.isNaN` instead of global `isNaN`.
+ eslint: [`no-restricted-globals`](https://eslint.org/docs/rules/no-restricted-globals)
+
+ > Why? The global `isNaN` coerces non-numbers to numbers, returning true for anything that coerces to NaN.
+ > If this behavior is desired, make it explicit.
+
+ ```javascript
+ // bad
+ isNaN('1.2'); // false
+ isNaN('1.2.3'); // true
+
+ // good
+ Number.isNaN('1.2.3'); // false
+ Number.isNaN(Number('1.2.3')); // true
+ ```
+
+
+ - [29.2](#standard-library--isfinite) Use `Number.isFinite` instead of global `isFinite`.
+ eslint: [`no-restricted-globals`](https://eslint.org/docs/rules/no-restricted-globals)
+
+ > Why? The global `isFinite` coerces non-numbers to numbers, returning true for anything that coerces to a finite number.
+ > If this behavior is desired, make it explicit.
+
+ ```javascript
+ // bad
+ isFinite('2e3'); // true
+
+ // good
+ Number.isFinite('2e3'); // false
+ Number.isFinite(parseInt('2e3', 10)); // true
+ ```
+
+**[⬆ back to top](#table-of-contents)**
+
## Testing
- - [28.1](#testing--yup) **Yup.**
+ - [30.1](#testing--yup) **Yup.**
```javascript
function foo() {
@@ -2981,70 +3830,71 @@ Other Style Guides
```
- - [28.2](#testing--for-real) **No, but seriously**:
- - Whichever testing framework you use, you should be writing tests!
- - Strive to write many small pure functions, and minimize where mutations occur.
- - Be cautious about stubs and mocks - they can make your tests more brittle.
- - We primarily use [`mocha`](https://www.npmjs.com/package/mocha) at Airbnb. [`tape`](https://www.npmjs.com/package/tape) is also used occasionally for small, separate modules.
- - 100% test coverage is a good goal to strive for, even if it's not always practical to reach it.
- - Whenever you fix a bug, _write a regression test_. A bug fixed without a regression test is almost certainly going to break again in the future.
+ - [30.2](#testing--for-real) **No, but seriously**:
+ - Whichever testing framework you use, you should be writing tests!
+ - Strive to write many small pure functions, and minimize where mutations occur.
+ - Be cautious about stubs and mocks - they can make your tests more brittle.
+ - We primarily use [`mocha`](https://www.npmjs.com/package/mocha) and [`jest`](https://www.npmjs.com/package/jest) at Airbnb. [`tape`](https://www.npmjs.com/package/tape) is also used occasionally for small, separate modules.
+ - 100% test coverage is a good goal to strive for, even if it’s not always practical to reach it.
+ - Whenever you fix a bug, *write a regression test*. A bug fixed without a regression test is almost certainly going to break again in the future.
**[⬆ back to top](#table-of-contents)**
-
## Performance
- [On Layout & Web Performance](https://www.kellegous.com/j/2013/01/26/layout-performance/)
- - [String vs Array Concat](https://jsperf.com/string-vs-array-concat/2)
- - [Try/Catch Cost In a Loop](https://jsperf.com/try-catch-in-loop-cost)
- - [Bang Function](https://jsperf.com/bang-function)
- - [jQuery Find vs Context, Selector](https://jsperf.com/jquery-find-vs-context-sel/13)
- - [innerHTML vs textContent for script text](https://jsperf.com/innerhtml-vs-textcontent-for-script-text)
- - [Long String Concatenation](https://jsperf.com/ya-string-concat)
- - [Are Javascript functions like `map()`, `reduce()`, and `filter()` optimized for traversing arrays?](https://www.quora.com/JavaScript-programming-language-Are-Javascript-functions-like-map-reduce-and-filter-already-optimized-for-traversing-array/answer/Quildreen-Motta)
+ - [String vs Array Concat](https://web.archive.org/web/20200414200857/https://jsperf.com/string-vs-array-concat/2)
+ - [Try/Catch Cost In a Loop](https://web.archive.org/web/20200414190827/https://jsperf.com/try-catch-in-loop-cost/12)
+ - [Bang Function](https://web.archive.org/web/20200414205426/https://jsperf.com/bang-function)
+ - [jQuery Find vs Context, Selector](https://web.archive.org/web/20200414200850/https://jsperf.com/jquery-find-vs-context-sel/164)
+ - [innerHTML vs textContent for script text](https://web.archive.org/web/20200414205428/https://jsperf.com/innerhtml-vs-textcontent-for-script-text)
+ - [Long String Concatenation](https://web.archive.org/web/20200414203914/https://jsperf.com/ya-string-concat/38)
+ - [Are JavaScript functions like `map()`, `reduce()`, and `filter()` optimized for traversing arrays?](https://www.quora.com/JavaScript-programming-language-Are-Javascript-functions-like-map-reduce-and-filter-already-optimized-for-traversing-array/answer/Quildreen-Motta)
- Loading...
**[⬆ back to top](#table-of-contents)**
-
## Resources
-**Learning ES6**
+**Learning ES6+**
- - [Draft ECMA 2015 (ES6) Spec](https://people.mozilla.org/~jorendorff/es6-draft.html)
- - [ExploringJS](http://exploringjs.com/)
- - [ES6 Compatibility Table](https://kangax.github.io/compat-table/es6/)
- - [Comprehensive Overview of ES6 Features](http://es6-features.org/)
+ - [Latest ECMA spec](https://tc39.github.io/ecma262/)
+ - [ExploringJS](https://exploringjs.com/)
+ - [ES6 Compatibility Table](https://compat-table.github.io/compat-table/es6/)
+ - [Comprehensive Overview of ES6 Features](https://web.archive.org/web/20240404212626/http://es6-features.org/)
+ - [JavaScript Roadmap](https://roadmap.sh/javascript)
**Read This**
- - [Standard ECMA-262](http://www.ecma-international.org/ecma-262/6.0/index.html)
+ - [Standard ECMA-262](https://www.ecma-international.org/ecma-262/6.0/index.html)
**Tools**
- Code Style Linters
- + [ESlint](http://eslint.org/) - [Airbnb Style .eslintrc](https://github.com/airbnb/javascript/blob/master/linters/.eslintrc)
- + [JSHint](http://jshint.com/) - [Airbnb Style .jshintrc](https://github.com/airbnb/javascript/blob/master/linters/.jshintrc)
- + [JSCS](https://github.com/jscs-dev/node-jscs) - [Airbnb Style Preset](https://github.com/jscs-dev/node-jscs/blob/master/presets/airbnb.json)
+ - [ESlint](https://eslint.org/) - [Airbnb Style .eslintrc](https://github.com/airbnb/javascript/blob/master/linters/.eslintrc)
+ - [JSHint](https://jshint.com/) - [Airbnb Style .jshintrc](https://github.com/airbnb/javascript/blob/master/linters/.jshintrc)
+ - Neutrino Preset - [@neutrinojs/airbnb](https://neutrinojs.org/packages/airbnb/)
**Other Style Guides**
- - [Google JavaScript Style Guide](https://google.github.io/styleguide/javascriptguide.xml)
+ - [Google JavaScript Style Guide](https://google.github.io/styleguide/jsguide.html)
+ - [Google JavaScript Style Guide (Old)](https://google.github.io/styleguide/javascriptguide.xml)
- [jQuery Core Style Guidelines](https://contribute.jquery.org/style-guide/js/)
- [Principles of Writing Consistent, Idiomatic JavaScript](https://github.com/rwaldron/idiomatic.js)
+ - [StandardJS](https://standardjs.com)
**Other Styles**
- [Naming this in nested functions](https://gist.github.com/cjohansen/4135065) - Christian Johansen
- [Conditional Callbacks](https://github.com/airbnb/javascript/issues/52) - Ross Allen
- [Popular JavaScript Coding Conventions on GitHub](http://sideeffect.kr/popularconvention/#javascript) - JeongHoon Byun
- - [Multiple var statements in JavaScript, not superfluous](http://benalman.com/news/2012/05/multiple-var-statements-javascript/) - Ben Alman
+ - [Multiple var statements in JavaScript, not superfluous](https://benalman.com/news/2012/05/multiple-var-statements-javascript/) - Ben Alman
**Further Reading**
- [Understanding JavaScript Closures](https://javascriptweblog.wordpress.com/2010/10/25/understanding-javascript-closures/) - Angus Croll
- - [Basic JavaScript for the impatient programmer](http://www.2ality.com/2013/06/basic-javascript.html) - Dr. Axel Rauschmayer
- - [You Might Not Need jQuery](http://youmightnotneedjquery.com/) - Zack Bloom & Adam Schwartz
+ - [Basic JavaScript for the impatient programmer](https://www.2ality.com/2013/06/basic-javascript.html) - Dr. Axel Rauschmayer
+ - [You Might Not Need jQuery](https://youmightnotneedjquery.com/) - Zack Bloom & Adam Schwartz
- [ES6 Features](https://github.com/lukehoban/es6features) - Luke Hoban
- [Frontend Guidelines](https://github.com/bendc/frontend-guidelines) - Benjamin De Cock
@@ -3052,7 +3902,7 @@ Other Style Guides
- [JavaScript: The Good Parts](https://www.amazon.com/JavaScript-Good-Parts-Douglas-Crockford/dp/0596517742) - Douglas Crockford
- [JavaScript Patterns](https://www.amazon.com/JavaScript-Patterns-Stoyan-Stefanov/dp/0596806752) - Stoyan Stefanov
- - [Pro JavaScript Design Patterns](https://www.amazon.com/JavaScript-Design-Patterns-Recipes-Problem-Solution/dp/159059908X) - Ross Harmes and Dustin Diaz
+ - [Pro JavaScript Design Patterns](https://www.amazon.com/JavaScript-Design-Patterns-Recipes-Problem-Solution/dp/159059908X) - Ross Harmes and Dustin Diaz
- [High Performance Web Sites: Essential Knowledge for Front-End Engineers](https://www.amazon.com/High-Performance-Web-Sites-Essential/dp/0596529309) - Steve Souders
- [Maintainable JavaScript](https://www.amazon.com/Maintainable-JavaScript-Nicholas-C-Zakas/dp/1449327680) - Nicholas C. Zakas
- [JavaScript Web Applications](https://www.amazon.com/JavaScript-Web-Applications-Alex-MacCaw/dp/144930351X) - Alex MacCaw
@@ -3061,112 +3911,121 @@ Other Style Guides
- [Secrets of the JavaScript Ninja](https://www.amazon.com/Secrets-JavaScript-Ninja-John-Resig/dp/193398869X) - John Resig and Bear Bibeault
- [Human JavaScript](http://humanjavascript.com/) - Henrik Joreteg
- [Superhero.js](http://superherojs.com/) - Kim Joar Bekkelund, Mads Mobæk, & Olav Bjorkoy
- - [JSBooks](http://jsbooks.revolunet.com/) - Julien Bouquillon
+ - [JSBooks](https://jsbooks.revolunet.com/) - Julien Bouquillon
- [Third Party JavaScript](https://www.manning.com/books/third-party-javascript) - Ben Vinegar and Anton Kovalyov
- - [Effective JavaScript: 68 Specific Ways to Harness the Power of JavaScript](http://amzn.com/0321812182) - David Herman
- - [Eloquent JavaScript](http://eloquentjavascript.net/) - Marijn Haverbeke
- - [You Don't Know JS: ES6 & Beyond](http://shop.oreilly.com/product/0636920033769.do) - Kyle Simpson
+ - [Effective JavaScript: 68 Specific Ways to Harness the Power of JavaScript](https://amzn.com/dp/0321812182) - David Herman
+ - [Eloquent JavaScript](https://eloquentjavascript.net/) - Marijn Haverbeke
+ - [You Don’t Know JS: ES6 & Beyond](https://shop.oreilly.com/product/0636920033769.do) - Kyle Simpson
**Blogs**
- - [JavaScript Weekly](http://javascriptweekly.com/)
+ - [JavaScript Weekly](https://javascriptweekly.com/)
- [JavaScript, JavaScript...](https://javascriptweblog.wordpress.com/)
- [Bocoup Weblog](https://bocoup.com/weblog)
- - [Adequately Good](http://www.adequatelygood.com/)
+ - [Adequately Good](https://www.adequatelygood.com/)
- [NCZOnline](https://www.nczonline.net/)
- [Perfection Kills](http://perfectionkills.com/)
- - [Ben Alman](http://benalman.com/)
+ - [Ben Alman](https://benalman.com/)
- [Dmitry Baranovskiy](http://dmitry.baranovskiy.com/)
- - [Dustin Diaz](http://dustindiaz.com/)
- - [nettuts](http://code.tutsplus.com/?s=javascript)
+ - [nettuts](https://code.tutsplus.com/?s=javascript)
**Podcasts**
- [JavaScript Air](https://javascriptair.com/)
- [JavaScript Jabber](https://devchat.tv/js-jabber/)
-
**[⬆ back to top](#table-of-contents)**
## In the Wild
This is a list of organizations that are using this style guide. Send us a pull request and we'll add you to the list.
+ - **123erfasst**: [123erfasst/javascript](https://github.com/123erfasst/javascript)
- **4Catalyzer**: [4Catalyzer/javascript](https://github.com/4Catalyzer/javascript)
- **Aan Zee**: [AanZee/javascript](https://github.com/AanZee/javascript)
- - **Adult Swim**: [adult-swim/javascript](https://github.com/adult-swim/javascript)
- **Airbnb**: [airbnb/javascript](https://github.com/airbnb/javascript)
+ - **AloPeyk**: [AloPeyk](https://github.com/AloPeyk)
+ - **AltSchool**: [AltSchool/javascript](https://github.com/AltSchool/javascript)
- **Apartmint**: [apartmint/javascript](https://github.com/apartmint/javascript)
- **Ascribe**: [ascribe/javascript](https://github.com/ascribe/javascript)
- - **Avalara**: [avalara/javascript](https://github.com/avalara/javascript)
- **Avant**: [avantcredit/javascript](https://github.com/avantcredit/javascript)
+ - **Axept**: [axept/javascript](https://github.com/axept/javascript)
- **Billabong**: [billabong/javascript](https://github.com/billabong/javascript)
- - **Bisk**: [bisk/javascript](https://github.com/Bisk/javascript/)
- - **Blendle**: [blendle/javascript](https://github.com/blendle/javascript)
+ - **Bisk**: [bisk](https://github.com/Bisk/)
- **Brainshark**: [brainshark/javascript](https://github.com/brainshark/javascript)
+ - **CaseNine**: [CaseNine/javascript](https://github.com/CaseNine/javascript)
+ - **Cerner**: [Cerner](https://github.com/cerner/)
- **Chartboost**: [ChartBoost/javascript-style-guide](https://github.com/ChartBoost/javascript-style-guide)
+ - **Coeur d'Alene Tribe**: [www.cdatribe-nsn.gov](https://www.cdatribe-nsn.gov)
- **ComparaOnline**: [comparaonline/javascript](https://github.com/comparaonline/javascript-style-guide)
- **Compass Learning**: [compasslearning/javascript-style-guide](https://github.com/compasslearning/javascript-style-guide)
- **DailyMotion**: [dailymotion/javascript](https://github.com/dailymotion/javascript)
- **DoSomething**: [DoSomething/eslint-config](https://github.com/DoSomething/eslint-config)
- **Digitpaint** [digitpaint/javascript](https://github.com/digitpaint/javascript)
+ - **Drupal**: [www.drupal.org](https://git.drupalcode.org/project/drupal/blob/8.6.x/core/.eslintrc.json)
- **Ecosia**: [ecosia/javascript](https://github.com/ecosia/javascript)
- - **Evernote**: [evernote/javascript-style-guide](https://github.com/evernote/javascript-style-guide)
- **Evolution Gaming**: [evolution-gaming/javascript](https://github.com/evolution-gaming/javascript)
- **EvozonJs**: [evozonjs/javascript](https://github.com/evozonjs/javascript)
- **ExactTarget**: [ExactTarget/javascript](https://github.com/ExactTarget/javascript)
- - **Expensify** [Expensify/Style-Guide](https://github.com/Expensify/Style-Guide/blob/master/javascript.md)
- **Flexberry**: [Flexberry/javascript-style-guide](https://github.com/Flexberry/javascript-style-guide)
- - **Gawker Media**: [gawkermedia/javascript](https://github.com/gawkermedia/javascript)
+ - **Gawker Media**: [gawkermedia](https://github.com/gawkermedia/)
- **General Electric**: [GeneralElectric/javascript](https://github.com/GeneralElectric/javascript)
+ - **Generation Tux**: [GenerationTux/javascript](https://github.com/generationtux/styleguide)
- **GoodData**: [gooddata/gdc-js-style](https://github.com/gooddata/gdc-js-style)
+ - **GreenChef**: [greenchef/javascript](https://github.com/greenchef/javascript)
- **Grooveshark**: [grooveshark/javascript](https://github.com/grooveshark/javascript)
+ - **Grupo-Abraxas**: [Grupo-Abraxas/javascript](https://github.com/Grupo-Abraxas/javascript)
+ - **Happeo**: [happeo/javascript](https://github.com/happeo/javascript)
- **How About We**: [howaboutwe/javascript](https://github.com/howaboutwe/javascript-style-guide)
- - **Huballin**: [huballin/javascript](https://github.com/huballin/javascript)
- **HubSpot**: [HubSpot/javascript](https://github.com/HubSpot/javascript)
- **Hyper**: [hyperoslo/javascript-playbook](https://github.com/hyperoslo/javascript-playbook/blob/master/style.md)
- - **InfoJobs**: [InfoJobs/JavaScript-Style-Guide](https://github.com/InfoJobs/JavaScript-Style-Guide)
- - **Intent Media**: [intentmedia/javascript](https://github.com/intentmedia/javascript)
+ - **ILIAS**: [ILIAS](https://github.com/ILIAS-eLearning/ILIAS)
+ - **InterCity Group**: [intercitygroup/javascript-style-guide](https://github.com/intercitygroup/javascript-style-guide)
- **Jam3**: [Jam3/Javascript-Code-Conventions](https://github.com/Jam3/Javascript-Code-Conventions)
- - **JeopardyBot**: [kesne/jeopardy-bot](https://github.com/kesne/jeopardy-bot/blob/master/STYLEGUIDE.md)
- **JSSolutions**: [JSSolutions/javascript](https://github.com/JSSolutions/javascript)
- - **KickorStick**: [kickorstick/javascript](https://github.com/kickorstick/javascript)
+ - **Kaplan Komputing**: [kaplankomputing/javascript](https://github.com/kaplankomputing/javascript)
+ - **KickorStick**: [kickorstick](https://github.com/kickorstick/)
- **Kinetica Solutions**: [kinetica/javascript](https://github.com/kinetica/Javascript-style-guide)
+ - **LEINWAND**: [LEINWAND/javascript](https://github.com/LEINWAND/javascript)
- **Lonely Planet**: [lonelyplanet/javascript](https://github.com/lonelyplanet/javascript)
- **M2GEN**: [M2GEN/javascript](https://github.com/M2GEN/javascript)
- **Mighty Spring**: [mightyspring/javascript](https://github.com/mightyspring/javascript)
- **MinnPost**: [MinnPost/javascript](https://github.com/MinnPost/javascript)
- **MitocGroup**: [MitocGroup/javascript](https://github.com/MitocGroup/javascript)
- - **ModCloth**: [modcloth/javascript](https://github.com/modcloth/javascript)
- - **Money Advice Service**: [moneyadviceservice/javascript](https://github.com/moneyadviceservice/javascript)
- - **Muber**: [muber/javascript](https://github.com/muber/javascript)
- - **National Geographic**: [natgeo/javascript](https://github.com/natgeo/javascript)
- - **National Park Service**: [nationalparkservice/javascript](https://github.com/nationalparkservice/javascript)
- - **Nimbl3**: [nimbl3/javascript](https://github.com/nimbl3/javascript)
+ - **Muber**: [muber](https://github.com/muber/)
+ - **National Geographic Society**: [natgeosociety](https://github.com/natgeosociety/)
+ - **NullDev**: [NullDevCo/JavaScript-Styleguide](https://github.com/NullDevCo/JavaScript-Styleguide)
+ - **Nulogy**: [nulogy/javascript](https://github.com/nulogy/javascript)
+ - **Orange Hill Development**: [orangehill/javascript](https://github.com/orangehill/javascript)
- **Orion Health**: [orionhealth/javascript](https://github.com/orionhealth/javascript)
- - **OutBoxSoft**: [OutBoxSoft/javascript](https://github.com/OutBoxSoft/javascript)
- **Peerby**: [Peerby/javascript](https://github.com/Peerby/javascript)
- - **Razorfish**: [razorfish/javascript-style-guide](https://github.com/razorfish/javascript-style-guide)
- - **reddit**: [reddit/styleguide/javascript](https://github.com/reddit/styleguide/tree/master/javascript)
- - **React**: [/facebook/react/blob/master/CONTRIBUTING.md#style-guide](https://github.com/facebook/react/blob/master/CONTRIBUTING.md#style-guide)
- - **REI**: [reidev/js-style-guide](https://github.com/rei/code-style-guides/blob/master/docs/javascript.md)
+ - **Pier 1**: [Pier1/javascript](https://github.com/pier1/javascript)
+ - **Qotto**: [Qotto/javascript-style-guide](https://github.com/Qotto/javascript-style-guide)
+ - **React**: [reactjs.org/docs/how-to-contribute.html#style-guide](https://reactjs.org/docs/how-to-contribute.html#style-guide)
- **Ripple**: [ripple/javascript-style-guide](https://github.com/ripple/javascript-style-guide)
- - **SeekingAlpha**: [seekingalpha/javascript-style-guide](https://github.com/seekingalpha/javascript-style-guide)
+ - **Sainsbury’s Supermarkets**: [jsainsburyplc](https://github.com/jsainsburyplc)
- **Shutterfly**: [shutterfly/javascript](https://github.com/shutterfly/javascript)
- - **Springload**: [springload/javascript](https://github.com/springload/javascript)
+ - **Sourcetoad**: [sourcetoad/javascript](https://github.com/sourcetoad/javascript)
+ - **Springload**: [springload](https://github.com/springload/)
- **StratoDem Analytics**: [stratodem/javascript](https://github.com/stratodem/javascript)
- **SteelKiwi Development**: [steelkiwi/javascript](https://github.com/steelkiwi/javascript)
- **StudentSphere**: [studentsphere/javascript](https://github.com/studentsphere/guide-javascript)
+ - **SwoopApp**: [swoopapp/javascript](https://github.com/swoopapp/javascript)
- **SysGarage**: [sysgarage/javascript-style-guide](https://github.com/sysgarage/javascript-style-guide)
- **Syzygy Warsaw**: [syzygypl/javascript](https://github.com/syzygypl/javascript)
- **Target**: [target/javascript](https://github.com/target/javascript)
+ - **Terra**: [terra](https://github.com/cerner?utf8=%E2%9C%93&q=terra&type=&language=)
- **TheLadders**: [TheLadders/javascript](https://github.com/TheLadders/javascript)
- **The Nerdery**: [thenerdery/javascript-standards](https://github.com/thenerdery/javascript-standards)
+ - **Tomify**: [tomprats](https://github.com/tomprats)
+ - **Traitify**: [traitify/eslint-config-traitify](https://github.com/traitify/eslint-config-traitify)
- **T4R Technology**: [T4R-Technology/javascript](https://github.com/T4R-Technology/javascript)
+ - **UrbanSim**: [urbansim](https://github.com/urbansim/)
- **VoxFeed**: [VoxFeed/javascript-style-guide](https://github.com/VoxFeed/javascript-style-guide)
- **WeBox Studio**: [weboxstudio/javascript](https://github.com/weboxstudio/javascript)
- **Weggo**: [Weggo/javascript](https://github.com/Weggo/javascript)
- **Zillow**: [zillow/javascript](https://github.com/zillow/javascript)
+ - **Zit Software**: [zit-software/javascript](https://github.com/zit-software/javascript)
- **ZocDoc**: [ZocDoc/javascript](https://github.com/ZocDoc/javascript)
**[⬆ back to top](#table-of-contents)**
@@ -3178,18 +4037,19 @@ Other Style Guides
-  **Brazilian Portuguese**: [armoucar/javascript-style-guide](https://github.com/armoucar/javascript-style-guide)
-  **Bulgarian**: [borislavvv/javascript](https://github.com/borislavvv/javascript)
-  **Catalan**: [fpmweb/javascript-style-guide](https://github.com/fpmweb/javascript-style-guide)
- -  **Chinese (Simplified)**: [sivan/javascript-style-guide](https://github.com/sivan/javascript-style-guide)
+ -  **Chinese (Simplified)**: [lin-123/javascript](https://github.com/lin-123/javascript)
-  **Chinese (Traditional)**: [jigsawye/javascript](https://github.com/jigsawye/javascript)
-  **French**: [nmussy/javascript-style-guide](https://github.com/nmussy/javascript-style-guide)
-  **German**: [timofurrer/javascript-style-guide](https://github.com/timofurrer/javascript-style-guide)
-  **Italian**: [sinkswim/javascript-style-guide](https://github.com/sinkswim/javascript-style-guide)
-  **Japanese**: [mitsuruog/javascript-style-guide](https://github.com/mitsuruog/javascript-style-guide)
- -  **Korean**: [tipjs/javascript-style-guide](https://github.com/tipjs/javascript-style-guide)
- -  **Polish**: [mjurczyk/javascript](https://github.com/mjurczyk/javascript)
- -  **Russian**: [uprock/javascript](https://github.com/uprock/javascript)
+ -  **Korean**: [ParkSB/javascript-style-guide](https://github.com/ParkSB/javascript-style-guide)
+ -  **Russian**: [leonidlebedev/javascript-airbnb](https://github.com/leonidlebedev/javascript-airbnb)
-  **Spanish**: [paolocarrasco/javascript-style-guide](https://github.com/paolocarrasco/javascript-style-guide)
-  **Thai**: [lvarayut/javascript-style-guide](https://github.com/lvarayut/javascript-style-guide)
- -  **Vietnam**: [giangpii/javascript-style-guide](https://github.com/giangpii/javascript-style-guide)
+ -  **Turkish**: [eraycetinay/javascript](https://github.com/eraycetinay/javascript)
+ -  **Ukrainian**: [ivanzusko/javascript](https://github.com/ivanzusko/javascript)
+ -  **Vietnam**: [dangkyokhoang/javascript-style-guide](https://github.com/dangkyokhoang/javascript-style-guide)
## The JavaScript Style Guide Guide
@@ -3203,12 +4063,11 @@ Other Style Guides
- [View Contributors](https://github.com/airbnb/javascript/graphs/contributors)
-
## License
(The MIT License)
-Copyright (c) 2014-2016 Airbnb
+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
@@ -3233,6 +4092,6 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
## Amendments
-We encourage you to fork this guide and change the rules to fit your team's style guide. Below, you may list some amendments to the style guide. This allows you to periodically update your style guide without having to deal with merge conflicts.
+We encourage you to fork this guide and change the rules to fit your team’s style guide. Below, you may list some amendments to the style guide. This allows you to periodically update your style guide without having to deal with merge conflicts.
# };
diff --git a/css-in-javascript/README.md b/css-in-javascript/README.md
index 59c1c7bcbd..2e6ab68a1b 100644
--- a/css-in-javascript/README.md
+++ b/css-in-javascript/README.md
@@ -1,6 +1,6 @@
# Airbnb CSS-in-JavaScript Style Guide
-*A mostly reasonable approach to CSS-in-JavaScript
+*A mostly reasonable approach to CSS-in-JavaScript*
## Table of Contents
@@ -14,7 +14,7 @@
- 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.
+ > Why? We access these keys as properties on the `styles` object in the component, so it is most convenient to use camelCase.
```js
// bad
@@ -34,7 +34,7 @@
- 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.
+ > Why? Similar to [BEM](https://getbem.com/introduction/), 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
@@ -64,7 +64,7 @@
- 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.
+ > 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
@@ -92,7 +92,7 @@
- Use a separate selector for sets of fallback styles.
- > Why? Keeping fallback styles contained in a separate object clarifies their purpose, which improves readability.
+ > Why? Keeping fallback styles contained in a separate object clarifies their purpose, which improves readability.
```js
// bad
@@ -133,7 +133,7 @@
- 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.
+ > 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
@@ -155,7 +155,7 @@
- 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.
+ > 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
@@ -176,7 +176,6 @@
export default withStyles(() => styles)(MyComponent);
-
// good
function MyComponent({ styles }) {
return (
@@ -198,7 +197,7 @@
- Leave a blank line between adjacent blocks at the same indentation level.
- > Why? The whitespace improves readability and reduces the likelihood of merge conflicts.
+ > Why? The whitespace improves readability and reduces the likelihood of merge conflicts.
```js
// bad
@@ -234,7 +233,7 @@
- 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.
+ > Why? Generating themed stylesheets can be expensive, so they are best for discrete sets of styles.
```jsx
// bad
@@ -373,7 +372,7 @@
- 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.
+ > 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
@@ -430,4 +429,4 @@
---
-CSS puns adapted from [Saijo George](http://saijogeorge.com/css-puns/).
+CSS puns adapted from [Saijo George](https://saijogeorge.com/css-puns/).
diff --git a/linters/.markdownlint.json b/linters/.markdownlint.json
new file mode 100644
index 0000000000..951337dbc5
--- /dev/null
+++ b/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 preceding 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 preceding 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
+}
diff --git a/linters/SublimeLinter/SublimeLinter.sublime-settings b/linters/SublimeLinter/SublimeLinter.sublime-settings
index 259dbaff6a..7ce44c9821 100644
--- a/linters/SublimeLinter/SublimeLinter.sublime-settings
+++ b/linters/SublimeLinter/SublimeLinter.sublime-settings
@@ -9,7 +9,7 @@
*
* @version 0.3.0
* @see https://github.com/SublimeLinter/SublimeLinter
- * @see http://www.jshint.com/docs/
+ * @see https://www.jshint.com/docs/
*/
{
"jshint_options":
diff --git a/package.json b/package.json
index a977f26b3d..a78bc250d4 100644
--- a/package.json
+++ b/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": "^0.29.0",
+ "markdownlint-cli": "^0.35.0"
+ }
}
diff --git a/packages/eslint-config-airbnb-base/.editorconfig b/packages/eslint-config-airbnb-base/.editorconfig
new file mode 120000
index 0000000000..1b3ce07def
--- /dev/null
+++ b/packages/eslint-config-airbnb-base/.editorconfig
@@ -0,0 +1 @@
+../../.editorconfig
\ No newline at end of file
diff --git a/packages/eslint-config-airbnb-base/.eslintrc b/packages/eslint-config-airbnb-base/.eslintrc
index 224149fda6..7606a50a46 100644
--- a/packages/eslint-config-airbnb-base/.eslintrc
+++ b/packages/eslint-config-airbnb-base/.eslintrc
@@ -3,6 +3,8 @@
"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,
+
+ "max-len": 0,
},
}
diff --git a/packages/eslint-config-airbnb-base/.npmrc b/packages/eslint-config-airbnb-base/.npmrc
new file mode 120000
index 0000000000..cba44bb384
--- /dev/null
+++ b/packages/eslint-config-airbnb-base/.npmrc
@@ -0,0 +1 @@
+../../.npmrc
\ No newline at end of file
diff --git a/packages/eslint-config-airbnb-base/CHANGELOG.md b/packages/eslint-config-airbnb-base/CHANGELOG.md
index 17f218bd65..51522a3f4e 100644
--- a/packages/eslint-config-airbnb-base/CHANGELOG.md
+++ b/packages/eslint-config-airbnb-base/CHANGELOG.md
@@ -1,3 +1,236 @@
+15.0.0 / 2021-11-08
+==================
+ - [breaking] drop eslint < 7, add eslint 8 (#2495)
+ - [breaking] add `exports`
+ - [patch] Improve `function-paren-newline` with `multiline-arguments` option (#2471)
+ - [patch] update default value for complexity (#2420)
+ - [patch] add disabled `no-unsafe-optional-chaining` rule
+ - [patch] arthmetic -> arithmetic (#2341)
+ - [patch] fix spelling of "than" (#2333)
+ - [patch] add `no-nonoctal-decimal-escape` rule
+ - [patch] `import/no-extraneous-dependencies`: Add .eslintrc.js to devDeps (#2329)
+ - [guide] Spread operator => Spread syntax (#2423)
+ - [guide] add references for eslint rules (#2419)
+ - [Docs] HTTP => HTTPS (#2489)
+ - [readme] some updates
+ - [meta] use `prepublishOnly` script for npm 7+
+ - [deps] update `eslint-plugin-import`, `eslint-plugin-react`, `object.entries`
+ - [dev deps] update `@babel/runtime`, `tape`
+
+14.2.1 / 2020-11-06
+==================
+ - [base] `no-restricted-globals`: add better messages (#2320)
+ - [base] add new core eslint rules, set to off
+ - [deps] update `confusing-browser-globals`, `object.assign`
+ - [deps] update `eslint-plugin-import`, use valid `import/no-cycle` `maxDepth` option (#2250, #2249)
+ - [dev deps] update `@babel/runtime`, `eslint-find-rules`, `eslint-plugin-import`
+
+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)
diff --git a/packages/eslint-config-airbnb-base/LICENSE.md b/packages/eslint-config-airbnb-base/LICENSE.md
new file mode 100644
index 0000000000..69d80c0252
--- /dev/null
+++ b/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.
diff --git a/packages/eslint-config-airbnb-base/README.md b/packages/eslint-config-airbnb-base/README.md
index d293a8ad90..6ddc34dac1 100644
--- a/packages/eslint-config-airbnb-base/README.md
+++ b/packages/eslint-config-airbnb-base/README.md
@@ -1,8 +1,12 @@
-# eslint-config-airbnb-base
+# eslint-config-airbnb-base [![Version Badge][npm-version-svg]][package-url]
-[](http://badge.fury.io/js/eslint-config-airbnb-base)
+[][package-url]
-This package provides Airbnb's base JS .eslintrc as an extensible shared config.
+[![github actions][actions-image]][actions-url]
+[![License][license-image]][license-url]
+[![Downloads][downloads-image]][downloads-url]
+
+This package provides Airbnb's base JS .eslintrc (without React plugins) as an extensible shared config.
## Usage
@@ -12,7 +16,24 @@ 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 @` for each listed peer dependency.
+
+
+ If using **npm < 5**, Linux/OSX users can run
+
```sh
(
export PKG=eslint-config-airbnb-base;
@@ -26,13 +47,32 @@ Our default export contains all of our ESLint rules, including ECMAScript 6+. It
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;
@@ -43,12 +83,16 @@ Lints ES5 and below. Requires `eslint` and `eslint-plugin-import`.
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/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
@@ -57,3 +101,12 @@ Consider adding test cases if you're making complicated rules changes, like anyt
You can run tests with `npm test`.
You can make sure this module lints with itself using `npm run lint`.
+
+[package-url]: https://npmjs.org/package/eslint-config-airbnb-base
+[npm-version-svg]: https://versionbadg.es/airbnb/javascript.svg
+[license-image]: https://img.shields.io/npm/l/eslint-config-airbnb-base.svg
+[license-url]: LICENSE.md
+[downloads-image]: https://img.shields.io/npm/dm/eslint-config-airbnb-base.svg
+[downloads-url]: https://npm-stat.com/charts.html?package=eslint-config-airbnb-base
+[actions-image]: https://img.shields.io/endpoint?url=https://github-actions-badge-u3jn4tfpocch.runkit.sh/airbnb/javascript
+[actions-url]: https://github.com/airbnb/javascript/actions
diff --git a/packages/eslint-config-airbnb-base/index.js b/packages/eslint-config-airbnb-base/index.js
index 4de657b075..825456b8a4 100644
--- a/packages/eslint-config-airbnb-base/index.js
+++ b/packages/eslint-config-airbnb-base/index.js
@@ -7,15 +7,11 @@ module.exports = {
'./rules/variables',
'./rules/es6',
'./rules/imports',
+ './rules/strict',
].map(require.resolve),
parserOptions: {
- ecmaVersion: 2017,
+ ecmaVersion: 2018,
sourceType: 'module',
- ecmaFeatures: {
- experimentalObjectRestSpread: true,
- },
- },
- rules: {
- strict: 'error',
},
+ rules: {},
};
diff --git a/packages/eslint-config-airbnb-base/legacy.js b/packages/eslint-config-airbnb-base/legacy.js
index 3de97acd21..e5c9089c75 100644
--- a/packages/eslint-config-airbnb-base/legacy.js
+++ b/packages/eslint-config-airbnb-base/legacy.js
@@ -13,10 +13,22 @@ module.exports = {
mocha: false,
jasmine: false
},
- ecmaFeatures: {},
- globals: {},
rules: {
'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'],
}
};
diff --git a/packages/eslint-config-airbnb-base/package.json b/packages/eslint-config-airbnb-base/package.json
index 783eaa5c85..8f039d4d7c 100644
--- a/packages/eslint-config-airbnb-base/package.json
+++ b/packages/eslint-config-airbnb-base/package.json
@@ -1,15 +1,34 @@
{
"name": "eslint-config-airbnb-base",
- "version": "9.0.0",
+ "version": "15.0.0",
"description": "Airbnb's base JS ESLint config, following our styleguide",
"main": "index.js",
+ "exports": {
+ ".": "./index.js",
+ "./legacy": "./legacy.js",
+ "./whitespace": "./whitespace.js",
+ "./rules/best-practices": "./rules/best-practices.js",
+ "./rules/es6": "./rules/es6.js",
+ "./rules/node": "./rules/node.js",
+ "./rules/style": "./rules/style.js",
+ "./rules/errors": "./rules/errors.js",
+ "./rules/imports": "./rules/imports.js",
+ "./rules/strict": "./rules/strict.js",
+ "./rules/variables": "./rules/variables.js",
+ "./package.json": "./package.json"
+ },
"scripts": {
- "lint": "eslint .",
+ "prelint": "eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git')",
+ "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) && safe-publish-latest",
+ "prepublishOnly": "eslint-find-rules --unused && npm test && safe-publish-latest",
+ "prepublish": "not-in-publish || npm run prepublishOnly",
"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 +40,11 @@
"config",
"airbnb",
"javascript",
- "styleguide"
+ "styleguide",
+ "es2015",
+ "es2016",
+ "es2017",
+ "es2018"
],
"author": "Jake Teton-Landis (https://twitter.com/@jitl)",
"contributors": [
@@ -45,20 +68,25 @@
},
"homepage": "https://github.com/airbnb/javascript",
"devDependencies": {
- "babel-preset-airbnb": "^2.1.1",
- "babel-tape-runner": "^2.0.1",
- "eslint": "^3.9.0",
- "eslint-find-rules": "^1.14.3",
- "eslint-plugin-import": "^2.0.1",
- "in-publish": "^2.0.0",
- "safe-publish-latest": "^1.1.1",
- "tape": "^4.6.2"
+ "@babel/runtime": "^7.25.6",
+ "babel-preset-airbnb": "^4.5.0",
+ "babel-tape-runner": "^3.0.0",
+ "eclint": "^2.8.1",
+ "eslint": "^7.32.0 || ^8.2.0",
+ "eslint-find-rules": "^4.1.0",
+ "eslint-plugin-import": "^2.30.0",
+ "in-publish": "^2.0.1",
+ "safe-publish-latest": "^2.0.0",
+ "tape": "^5.9.0"
},
"peerDependencies": {
- "eslint": "^3.9.0",
- "eslint-plugin-import": "^2.0.1"
+ "eslint": "^7.32.0 || ^8.2.0",
+ "eslint-plugin-import": "^2.30.0"
},
"engines": {
- "node": ">= 4"
+ "node": "^10.12.0 || >=12.0.0"
+ },
+ "dependencies": {
+ "confusing-browser-globals": "^1.0.11"
}
}
diff --git a/packages/eslint-config-airbnb-base/rules/best-practices.js b/packages/eslint-config-airbnb-base/rules/best-practices.js
index b7e3f60630..09c247451a 100644
--- a/packages/eslint-config-airbnb-base/rules/best-practices.js
+++ b/packages/eslint-config-airbnb-base/rules/best-practices.js
@@ -1,66 +1,97 @@
module.exports = {
rules: {
// enforces getter/setter pairs in objects
+ // https://eslint.org/docs/rules/accessor-pairs
'accessor-pairs': 'off',
// enforces return statements in callbacks of array's methods
- // http://eslint.org/docs/rules/array-callback-return
- 'array-callback-return': 'error',
+ // https://eslint.org/docs/rules/array-callback-return
+ 'array-callback-return': ['error', { allowImplicit: true }],
// treat var statements as if they were block scoped
+ // https://eslint.org/docs/rules/block-scoped-var
'block-scoped-var': 'error',
// specify the maximum cyclomatic complexity allowed in a program
- complexity: ['off', 11],
+ // https://eslint.org/docs/rules/complexity
+ complexity: ['off', 20],
// enforce that class methods use "this"
- // http://eslint.org/docs/rules/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
+ // https://eslint.org/docs/rules/consistent-return
'consistent-return': 'error',
// specify curly brace conventions for all control statements
- curly: ['error', 'multi-line'],
+ // https://eslint.org/docs/rules/curly
+ curly: ['error', 'multi-line'], // multiline
// require default case in switch statements
+ // https://eslint.org/docs/rules/default-case
'default-case': ['error', { commentPattern: '^no default$' }],
+ // Enforce default clauses in switch statements to be last
+ // https://eslint.org/docs/rules/default-case-last
+ 'default-case-last': 'error',
+
+ // https://eslint.org/docs/rules/default-param-last
+ 'default-param-last': 'error',
+
// encourages use of dot notation whenever possible
+ // https://eslint.org/docs/rules/dot-notation
'dot-notation': ['error', { allowKeywords: true }],
// enforces consistent newlines before or after dots
- // http://eslint.org/docs/rules/dot-location
+ // https://eslint.org/docs/rules/dot-location
'dot-location': ['error', 'property'],
// require the use of === and !==
- // http://eslint.org/docs/rules/eqeqeq
- eqeqeq: ['error', '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
+ 'grouped-accessor-pairs': 'error',
// make sure for-in loops have an if statement
+ // https://eslint.org/docs/rules/guard-for-in
'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
+ // https://eslint.org/docs/rules/no-alert
+ // TODO: enable, semver-major
'no-alert': 'warn',
// disallow use of arguments.caller or arguments.callee
+ // https://eslint.org/docs/rules/no-caller
'no-caller': 'error',
// disallow lexical declarations in case/default clauses
- // http://eslint.org/docs/rules/no-case-declarations.html
+ // https://eslint.org/docs/rules/no-case-declarations
'no-case-declarations': 'error',
+ // Disallow returning value in constructor
+ // https://eslint.org/docs/rules/no-constructor-return
+ 'no-constructor-return': 'error',
+
// disallow division operators explicitly at beginning of regular expression
- // http://eslint.org/docs/rules/no-div-regex
+ // https://eslint.org/docs/rules/no-div-regex
'no-div-regex': 'off',
// disallow else after a return in an if
- 'no-else-return': 'error',
+ // 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
+ // https://eslint.org/docs/rules/no-empty-function
'no-empty-function': ['error', {
allow: [
'arrowFunctions',
@@ -70,39 +101,52 @@ module.exports = {
}],
// disallow empty destructuring patterns
- // http://eslint.org/docs/rules/no-empty-pattern
+ // https://eslint.org/docs/rules/no-empty-pattern
'no-empty-pattern': 'error',
+ // Disallow empty static blocks
+ // https://eslint.org/docs/latest/rules/no-empty-static-block
+ // TODO: semver-major, enable
+ 'no-empty-static-block': 'off',
+
// disallow comparisons to null without a type-checking operator
+ // https://eslint.org/docs/rules/no-eq-null
'no-eq-null': 'off',
// disallow use of eval()
+ // https://eslint.org/docs/rules/no-eval
'no-eval': 'error',
// disallow adding to native types
+ // https://eslint.org/docs/rules/no-extend-native
'no-extend-native': 'error',
// disallow unnecessary function binding
+ // https://eslint.org/docs/rules/no-extra-bind
'no-extra-bind': 'error',
// disallow Unnecessary Labels
- // http://eslint.org/docs/rules/no-extra-label
+ // https://eslint.org/docs/rules/no-extra-label
'no-extra-label': 'error',
// disallow fallthrough of case statements
+ // https://eslint.org/docs/rules/no-fallthrough
'no-fallthrough': 'error',
// disallow the use of leading or trailing decimal points in numeric literals
+ // https://eslint.org/docs/rules/no-floating-decimal
'no-floating-decimal': 'error',
// disallow reassignments of native objects or read-only globals
- // http://eslint.org/docs/rules/no-global-assign
+ // https://eslint.org/docs/rules/no-global-assign
'no-global-assign': ['error', { exceptions: [] }],
+
// deprecated in favor of no-global-assign
+ // https://eslint.org/docs/rules/no-native-reassign
'no-native-reassign': 'off',
// disallow implicit type conversions
- // http://eslint.org/docs/rules/no-implicit-coercion
+ // https://eslint.org/docs/rules/no-implicit-coercion
'no-implicit-coercion': ['off', {
boolean: false,
number: true,
@@ -111,29 +155,35 @@ module.exports = {
}],
// disallow var and named functions in global scope
- // http://eslint.org/docs/rules/no-implicit-globals
+ // https://eslint.org/docs/rules/no-implicit-globals
'no-implicit-globals': 'off',
// disallow use of eval()-like methods
+ // https://eslint.org/docs/rules/no-implied-eval
'no-implied-eval': 'error',
// disallow this keywords outside of classes or class-like objects
+ // https://eslint.org/docs/rules/no-invalid-this
'no-invalid-this': 'off',
// disallow usage of __iterator__ property
+ // https://eslint.org/docs/rules/no-iterator
'no-iterator': 'error',
- // disallow use of labels for anything other then loops and switches
+ // disallow use of labels for anything other than loops and switches
+ // https://eslint.org/docs/rules/no-labels
'no-labels': ['error', { allowLoop: false, allowSwitch: false }],
// disallow unnecessary nested blocks
+ // https://eslint.org/docs/rules/no-lone-blocks
'no-lone-blocks': 'error',
// disallow creation of functions within loops
+ // https://eslint.org/docs/rules/no-loop-func
'no-loop-func': 'error',
// disallow magic numbers
- // http://eslint.org/docs/rules/no-magic-numbers
+ // https://eslint.org/docs/rules/no-magic-numbers
'no-magic-numbers': ['off', {
ignore: [],
ignoreArrayIndexes: true,
@@ -142,121 +192,233 @@ module.exports = {
}],
// disallow use of multiple spaces
- 'no-multi-spaces': 'error',
+ // https://eslint.org/docs/rules/no-multi-spaces
+ 'no-multi-spaces': ['error', {
+ ignoreEOLComments: false,
+ }],
// disallow use of multiline strings
+ // https://eslint.org/docs/rules/no-multi-str
'no-multi-str': 'error',
// disallow use of new operator when not part of the assignment or comparison
+ // https://eslint.org/docs/rules/no-new
'no-new': 'error',
// disallow use of new operator for Function object
+ // https://eslint.org/docs/rules/no-new-func
'no-new-func': 'error',
// disallows creating new instances of String, Number, and Boolean
+ // https://eslint.org/docs/rules/no-new-wrappers
'no-new-wrappers': 'error',
+ // Disallow \8 and \9 escape sequences in string literals
+ // https://eslint.org/docs/rules/no-nonoctal-decimal-escape
+ 'no-nonoctal-decimal-escape': 'error',
+
+ // Disallow calls to the Object constructor without an argument
+ // https://eslint.org/docs/latest/rules/no-object-constructor
+ // TODO: enable, semver-major
+ 'no-object-constructor': 'off',
+
// disallow use of (old style) octal literals
+ // https://eslint.org/docs/rules/no-octal
'no-octal': 'error',
// disallow use of octal escape sequences in string literals, such as
// var foo = 'Copyright \251';
+ // https://eslint.org/docs/rules/no-octal-escape
'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': ['error', { 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
+ // https://eslint.org/docs/rules/no-proto
'no-proto': 'error',
- // disallow declaring the same variable more then once
+ // disallow declaring the same variable more than once
+ // https://eslint.org/docs/rules/no-redeclare
'no-redeclare': 'error',
// disallow certain object properties
- // http://eslint.org/docs/rules/no-restricted-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': 'error',
+ // https://eslint.org/docs/rules/no-return-assign
+ 'no-return-assign': ['error', 'always'],
+
+ // disallow redundant `return await`
+ // https://eslint.org/docs/rules/no-return-await
+ 'no-return-await': 'error',
// disallow use of `javascript:` urls.
+ // https://eslint.org/docs/rules/no-script-url
'no-script-url': 'error',
// disallow self assignment
- // http://eslint.org/docs/rules/no-self-assign
- 'no-self-assign': 'error',
+ // https://eslint.org/docs/rules/no-self-assign
+ 'no-self-assign': ['error', {
+ props: true,
+ }],
// disallow comparisons where both sides are exactly the same
+ // https://eslint.org/docs/rules/no-self-compare
'no-self-compare': 'error',
// disallow use of comma operator
+ // https://eslint.org/docs/rules/no-sequences
'no-sequences': 'error',
// restrict what can be thrown as an exception
+ // https://eslint.org/docs/rules/no-throw-literal
'no-throw-literal': 'error',
// disallow unmodified conditions of loops
- // http://eslint.org/docs/rules/no-unmodified-loop-condition
+ // https://eslint.org/docs/rules/no-unmodified-loop-condition
'no-unmodified-loop-condition': 'off',
// disallow usage of expressions in statement position
+ // https://eslint.org/docs/rules/no-unused-expressions
'no-unused-expressions': ['error', {
allowShortCircuit: false,
allowTernary: false,
+ allowTaggedTemplates: false,
}],
// disallow unused labels
- // http://eslint.org/docs/rules/no-unused-labels
+ // https://eslint.org/docs/rules/no-unused-labels
'no-unused-labels': 'error',
// disallow unnecessary .call() and .apply()
+ // https://eslint.org/docs/rules/no-useless-call
'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
+ // https://eslint.org/docs/rules/no-useless-concat
'no-useless-concat': 'error',
// disallow unnecessary string escaping
- // http://eslint.org/docs/rules/no-useless-escape
+ // https://eslint.org/docs/rules/no-useless-escape
'no-useless-escape': 'error',
// disallow redundant return; keywords
- // http://eslint.org/docs/rules/no-useless-return
+ // https://eslint.org/docs/rules/no-useless-return
'no-useless-return': 'error',
// disallow use of void operator
- // http://eslint.org/docs/rules/no-void
+ // https://eslint.org/docs/rules/no-void
'no-void': 'error',
// disallow usage of configurable warning terms in comments: e.g. todo
+ // https://eslint.org/docs/rules/no-warning-comments
'no-warning-comments': ['off', { terms: ['todo', 'fixme', 'xxx'], location: 'start' }],
// disallow use of the with statement
+ // https://eslint.org/docs/rules/no-with
'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',
+
+ // Prefer Object.hasOwn() over Object.prototype.hasOwnProperty.call()
+ // https://eslint.org/docs/rules/prefer-object-has-own
+ // TODO: semver-major: enable thus rule, once eslint v8.5.0 is required
+ 'prefer-object-has-own': 'off',
+
+ // https://eslint.org/docs/rules/prefer-regex-literals
+ 'prefer-regex-literals': ['error', {
+ disallowRedundantWrapping: true,
+ }],
+
// require use of the second argument for parseInt()
+ // https://eslint.org/docs/rules/radix
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
+ // https://eslint.org/docs/rules/vars-on-top
'vars-on-top': 'error',
// require immediate function invocation to be wrapped in parentheses
- // http://eslint.org/docs/rules/wrap-iife.html
+ // https://eslint.org/docs/rules/wrap-iife.html
'wrap-iife': ['error', 'outside', { functionPrototypeMethods: false }],
// require or disallow Yoda conditions
+ // https://eslint.org/docs/rules/yoda
yoda: 'error'
}
};
diff --git a/packages/eslint-config-airbnb-base/rules/errors.js b/packages/eslint-config-airbnb-base/rules/errors.js
index 1849e8db4d..a3dda4e510 100644
--- a/packages/eslint-config-airbnb-base/rules/errors.js
+++ b/packages/eslint-config-airbnb-base/rules/errors.js
@@ -1,13 +1,24 @@
module.exports = {
rules: {
- // 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 “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': ['error', 'always'],
@@ -15,6 +26,11 @@ module.exports = {
// disallow use of console
'no-console': 'warn',
+ // Disallows expressions where the operation doesn't affect the value
+ // https://eslint.org/docs/rules/no-constant-binary-expression
+ // TODO: semver-major, enable
+ 'no-constant-binary-expression': 'off',
+
// disallow use of constant expressions in conditions
'no-constant-condition': 'warn',
@@ -27,6 +43,10 @@ module.exports = {
// disallow duplicate arguments in functions
'no-dupe-args': 'error',
+ // Disallow duplicate conditions in if-else-if chains
+ // https://eslint.org/docs/rules/no-dupe-else-if
+ 'no-dupe-else-if': 'error',
+
// disallow duplicate keys when creating object literals
'no-dupe-keys': 'error',
@@ -43,15 +63,17 @@ module.exports = {
'no-ex-assign': 'error',
// disallow double-negation boolean casts in a boolean context
- // http://eslint.org/docs/rules/no-extra-boolean-cast
+ // 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
+ // 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
@@ -60,6 +82,9 @@ module.exports = {
// disallow overwriting functions written as function declarations
'no-func-assign': 'error',
+ // https://eslint.org/docs/rules/no-import-assign
+ 'no-import-assign': 'error',
+
// disallow function or variable declarations in nested blocks
'no-inner-declarations': 'error',
@@ -69,50 +94,96 @@ module.exports = {
// disallow irregular whitespace outside of strings and comments
'no-irregular-whitespace': 'error',
+ // Disallow Number Literals That Lose Precision
+ // https://eslint.org/docs/rules/no-loss-of-precision
+ 'no-loss-of-precision': 'error',
+
+ // 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': 'error',
+ // Disallow new operators with global non-constructor functions
+ // https://eslint.org/docs/latest/rules/no-new-native-nonconstructor
+ // TODO: semver-major, enable
+ 'no-new-native-nonconstructor': 'off',
+
+ // Disallow returning values from Promise executor functions
+ // https://eslint.org/docs/rules/no-promise-executor-return
+ 'no-promise-executor-return': 'error',
+
// disallow use of Object.prototypes builtins directly
- // http://eslint.org/docs/rules/no-prototype-builtins
+ // https://eslint.org/docs/rules/no-prototype-builtins
'no-prototype-builtins': 'error',
// disallow multiple spaces in a regular expression literal
'no-regex-spaces': 'error',
+ // Disallow returning values from setters
+ // https://eslint.org/docs/rules/no-setter-return
+ 'no-setter-return': 'error',
+
// disallow sparse arrays
'no-sparse-arrays': 'error',
// Disallow template literal placeholder syntax in regular strings
- // http://eslint.org/docs/rules/no-template-curly-in-string
+ // 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
+ // 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': 'error',
+ // Disallow loops with a body that allows only one iteration
+ // https://eslint.org/docs/rules/no-unreachable-loop
+ 'no-unreachable-loop': ['error', {
+ ignore: [], // WhileStatement, DoWhileStatement, ForStatement, ForInStatement, ForOfStatement
+ }],
+
// disallow return/throw/break/continue inside finally blocks
- // http://eslint.org/docs/rules/no-unsafe-finally
+ // https://eslint.org/docs/rules/no-unsafe-finally
'no-unsafe-finally': 'error',
// disallow negating the left operand of relational operators
- // http://eslint.org/docs/rules/no-unsafe-negation
+ // https://eslint.org/docs/rules/no-unsafe-negation
'no-unsafe-negation': 'error',
+
+ // disallow use of optional chaining in contexts where the undefined value is not allowed
+ // https://eslint.org/docs/rules/no-unsafe-optional-chaining
+ 'no-unsafe-optional-chaining': ['error', { disallowArithmeticOperators: true }],
+
+ // Disallow Unused Private Class Members
+ // https://eslint.org/docs/rules/no-unused-private-class-members
+ // TODO: enable once eslint 7 is dropped (which is semver-major)
+ 'no-unused-private-class-members': 'off',
+
+ // Disallow useless backreferences in regular expressions
+ // https://eslint.org/docs/rules/no-useless-backreference
+ 'no-useless-backreference': 'error',
+
// 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': 'error',
// ensure JSDoc comments are valid
- // http://eslint.org/docs/rules/valid-jsdoc
+ // https://eslint.org/docs/rules/valid-jsdoc
'valid-jsdoc': 'off',
// ensure that the results of typeof are compared against a valid string
- // http://eslint.org/docs/rules/valid-typeof
+ // https://eslint.org/docs/rules/valid-typeof
'valid-typeof': ['error', { requireStringLiterals: true }],
}
};
diff --git a/packages/eslint-config-airbnb-base/rules/es6.js b/packages/eslint-config-airbnb-base/rules/es6.js
index 063ee2cfa5..5e59cbebf4 100644
--- a/packages/eslint-config-airbnb-base/rules/es6.js
+++ b/packages/eslint-config-airbnb-base/rules/es6.js
@@ -13,35 +13,33 @@ module.exports = {
rules: {
// enforces no braces where they can be omitted
- // http://eslint.org/docs/rules/arrow-body-style
+ // 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
- // http://eslint.org/docs/rules/arrow-parens
- 'arrow-parens': ['error', 'as-needed', {
- requireForBlockBody: true,
- }],
+ // 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
+ // https://eslint.org/docs/rules/arrow-spacing
'arrow-spacing': ['error', { before: true, after: true }],
// verify super() callings in constructors
'constructor-super': 'error',
// enforce the spacing around the * in generator functions
- // http://eslint.org/docs/rules/generator-star-spacing
+ // 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
+ // 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
+ // https://eslint.org/docs/rules/no-confusing-arrow
'no-confusing-arrow': ['error', {
allowParens: true,
}],
@@ -50,35 +48,48 @@ module.exports = {
'no-const-assign': 'error',
// disallow duplicate class members
- // http://eslint.org/docs/rules/no-dupe-class-members
+ // 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': 'error',
+ // https://eslint.org/docs/rules/no-duplicate-imports
+ // replaced by https://github.com/import-js/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
+ // 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
+ 'no-restricted-exports': ['error', {
+ restrictedNamedExports: [
+ 'default', // use `export default` to provide a default export
+ 'then', // this will cause tons of confusion when your module is dynamically `import()`ed, and will break in most node ESM versions
+ ],
+ }],
+
// disallow specific imports
- // http://eslint.org/docs/rules/no-restricted-imports
- 'no-restricted-imports': 'off',
+ // 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
+ // 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
+ // 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
+ // 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
+ // https://eslint.org/docs/rules/no-useless-rename
'no-useless-rename': ['error', {
ignoreDestructuring: false,
ignoreImport: false,
@@ -89,7 +100,7 @@ module.exports = {
'no-var': 'error',
// require method and property shorthand syntax for object literals
- // http://eslint.org/docs/rules/object-shorthand
+ // https://eslint.org/docs/rules/object-shorthand
'object-shorthand': ['error', 'always', {
ignoreConstructors: false,
avoidQuotes: true,
@@ -107,53 +118,68 @@ module.exports = {
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
- // http://eslint.org/docs/rules/prefer-numeric-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?
+ // https://eslint.org/docs/rules/prefer-reflect
'prefer-reflect': 'off',
// use rest parameters instead of arguments
- // http://eslint.org/docs/rules/prefer-rest-params
+ // 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
+ // suggest using the spread syntax instead of .apply()
+ // 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
+ // 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
+ // https://eslint.org/docs/rules/require-yield
'require-yield': 'error',
// enforce spacing between object rest-spread
- // http://eslint.org/docs/rules/rest-spread-spacing
+ // https://eslint.org/docs/rules/rest-spread-spacing
'rest-spread-spacing': ['error', 'never'],
// import sorting
- // http://eslint.org/docs/rules/sort-imports
+ // 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
- // http://eslint.org/docs/rules/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
+ // 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
+ // https://eslint.org/docs/rules/yield-star-spacing
'yield-star-spacing': ['error', 'after']
}
};
diff --git a/packages/eslint-config-airbnb-base/rules/imports.js b/packages/eslint-config-airbnb-base/rules/imports.js
index a8f4269cbd..d36e4908fa 100644
--- a/packages/eslint-config-airbnb-base/rules/imports.js
+++ b/packages/eslint-config-airbnb-base/rules/imports.js
@@ -13,11 +13,12 @@ module.exports = {
settings: {
'import/resolver': {
node: {
- extensions: ['.js', '.json']
+ extensions: ['.mjs', '.js', '.json']
}
},
'import/extensions': [
'.js',
+ '.mjs',
'.jsx',
],
'import/core-modules': [
@@ -32,143 +33,251 @@ module.exports = {
// Static analysis:
// ensure imports point to files/modules that can be resolved
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-unresolved.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-unresolved.md
'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': 'off',
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/named.md#when-not-to-use-it
+ '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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/default.md#when-not-to-use-it
'import/default': 'off',
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/namespace.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/namespace.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/export.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-named-as-default.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-named-as-default-member.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-deprecated.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-extraneous-dependencies.md
+ // paths are treated both as absolute paths, and relative to process.cwd()
'import/no-extraneous-dependencies': ['error', {
- devDependencies: false,
+ 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
+ '**/.eslintrc.js' // eslint config
+ ],
optionalDependencies: false,
}],
// Forbid mutable exports
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-mutable-exports.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-mutable-exports.md
'import/no-mutable-exports': 'error',
// Module systems:
// disallow require()
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-commonjs.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-commonjs.md
'import/no-commonjs': 'off',
// disallow AMD require/define
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-amd.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-amd.md
'import/no-amd': 'error',
// No Node.js builtin modules
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-nodejs-modules.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-nodejs-modules.md
// TODO: enable?
'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', 'absolute-first'],
+ // https://github.com/import-js/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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/imports-first.md
// 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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-duplicates.md
'import/no-duplicates': 'error',
// disallow namespace imports
// TODO: enable?
- // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-namespace.md
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-namespace.md
'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
- 'import/extensions': ['error', 'always', {
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/extensions.md
+ 'import/extensions': ['error', 'ignorePackages', {
js: 'never',
+ mjs: 'never',
jsx: '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': ['off', {
- groups: ['builtin', 'external', 'internal', 'parent', 'sibling', 'index'],
- 'newlines-between': 'never',
- }],
+ // ensure absolute imports are above relative imports and that unassigned imports are ignored
+ // https://github.com/import-js/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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/newline-after-import.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/prefer-default-export.md
'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
+ // https://github.com/import-js/eslint-plugin-import/blob/master/docs/rules/no-restricted-paths.md
'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
+ // https://github.com/import-js/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
+ // https://github.com/import-js/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
+ // https://github.com/import-js/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
+ // https://github.com/import-js/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
+ // https://github.com/import-js/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
+ // https://github.com/import-js/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
+ // https://github.com/import-js/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/import-js/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/import-js/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/import-js/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/import-js/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/import-js/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/import-js/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/import-js/eslint-plugin-import/blob/44a038c06487964394b1e15b64f3bd34e5d40cde/docs/rules/no-self-import.md
+ 'import/no-self-import': 'error',
+
+ // Forbid cyclical dependencies between modules
+ // https://github.com/import-js/eslint-plugin-import/blob/d81f48a2506182738409805f5272eff4d77c9348/docs/rules/no-cycle.md
+ 'import/no-cycle': ['error', { maxDepth: '∞' }],
+
+ // Ensures that there are no useless path segments
+ // https://github.com/import-js/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/import-js/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/import-js/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/import-js/eslint-plugin-import/blob/f63dd261809de6883b13b6b5b960e6d7f42a7813/docs/rules/no-unused-modules.md
+ // TODO: enable once it supports CJS
+ 'import/no-unused-modules': ['off', {
+ ignoreExports: [],
+ missingExports: true,
+ unusedExports: true,
+ }],
+
+ // Reports the use of import declarations with CommonJS exports in any module except for the main module.
+ // https://github.com/import-js/eslint-plugin-import/blob/1012eb951767279ce3b540a4ec4f29236104bb5b/docs/rules/no-import-module-exports.md
+ 'import/no-import-module-exports': ['error', {
+ exceptions: [],
+ }],
+
+ // Use this rule to prevent importing packages through relative paths.
+ // https://github.com/import-js/eslint-plugin-import/blob/1012eb951767279ce3b540a4ec4f29236104bb5b/docs/rules/no-relative-packages.md
+ 'import/no-relative-packages': 'error',
+
+ // enforce a consistent style for type specifiers (inline or top-level)
+ // https://github.com/import-js/eslint-plugin-import/blob/d5fc8b670dc8e6903dbb7b0894452f60c03089f5/docs/rules/consistent-type-specifier-style.md
+ // TODO, semver-major: enable (just in case)
+ 'import/consistent-type-specifier-style': ['off', 'prefer-inline'],
+
+ // Reports the use of empty named import blocks.
+ // https://github.com/import-js/eslint-plugin-import/blob/d5fc8b670dc8e6903dbb7b0894452f60c03089f5/docs/rules/no-empty-named-blocks.md
+ // TODO, semver-minor: enable
+ 'import/no-empty-named-blocks': 'off',
},
};
diff --git a/packages/eslint-config-airbnb-base/rules/node.js b/packages/eslint-config-airbnb-base/rules/node.js
index e4a71a6a5a..b178d7f909 100644
--- a/packages/eslint-config-airbnb-base/rules/node.js
+++ b/packages/eslint-config-airbnb-base/rules/node.js
@@ -8,12 +8,16 @@ module.exports = {
'callback-return': 'off',
// require all requires be top-level
- // http://eslint.org/docs/rules/global-require
+ // https://eslint.org/docs/rules/global-require
'global-require': 'error',
// enforces error handling in callbacks (node environment)
'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': ['off', false],
@@ -21,7 +25,7 @@ module.exports = {
'no-new-require': 'error',
// disallow string concatenation with __dirname and __filename
- // http://eslint.org/docs/rules/no-path-concat
+ // https://eslint.org/docs/rules/no-path-concat
'no-path-concat': 'error',
// disallow use of process.env
diff --git a/packages/eslint-config-airbnb-base/rules/style.js b/packages/eslint-config-airbnb-base/rules/style.js
index c9e7c0f7a9..2e7f6fed44 100644
--- a/packages/eslint-config-airbnb-base/rules/style.js
+++ b/packages/eslint-config-airbnb-base/rules/style.js
@@ -1,23 +1,71 @@
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': ['error', 'never'],
// enforce spacing inside single-line blocks
- // http://eslint.org/docs/rules/block-spacing
+ // https://eslint.org/docs/rules/block-spacing
'block-spacing': ['error', 'always'],
// enforce one true brace style
'brace-style': ['error', '1tbs', { allowSingleLine: true }],
// require camel case names
- camelcase: ['error', { 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': ['error', { before: false, after: true }],
// enforce one true comma style
- 'comma-style': ['error', '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': ['error', 'never'],
@@ -28,29 +76,37 @@ module.exports = {
// enforce newline at the end of file, with no multiple empty lines
'eol-last': ['error', 'always'],
+ // https://eslint.org/docs/rules/function-call-argument-newline
+ 'function-call-argument-newline': ['error', 'consistent'],
+
// enforce spacing between functions and their invocations
- // http://eslint.org/docs/rules/func-call-spacing
+ // 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
- // http://eslint.org/docs/rules/func-name-matching
+ // https://eslint.org/docs/rules/func-name-matching
'func-name-matching': ['off', 'always', {
- includeCommonJSModuleExports: false
+ includeCommonJSModuleExports: false,
+ considerPropertyDescriptor: true,
}],
// require function expressions to have a name
- // http://eslint.org/docs/rules/func-names
+ // https://eslint.org/docs/rules/func-names
'func-names': 'warn',
// enforces use of function declarations or expressions
- // http://eslint.org/docs/rules/func-style
+ // https://eslint.org/docs/rules/func-style
// TODO: enable
'func-style': ['off', 'expression'],
- // Blacklist certain identifiers to prevent them being used
- // http://eslint.org/docs/rules/id-blacklist
- 'id-blacklist': 'off',
+ // require line breaks inside function parentheses if there are line breaks between parameters
+ // https://eslint.org/docs/rules/function-paren-newline
+ 'function-paren-newline': ['error', 'multiline-arguments'],
+
+ // disallow specified identifiers
+ // https://eslint.org/docs/rules/id-denylist
+ 'id-denylist': 'off',
// this option enforces minimum and maximum identifier lengths
// (variable names, property names etc.)
@@ -59,16 +115,17 @@ module.exports = {
// require identifiers to match the provided regular expression
'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
+ // https://eslint.org/docs/rules/indent
indent: ['error', 2, {
SwitchCase: 1,
VariableDeclarator: 1,
outerIIFEBody: 1,
// MemberExpression: null,
- // CallExpression: {
- // parameters: null,
- // },
FunctionDeclaration: {
parameters: 1,
body: 1
@@ -76,11 +133,21 @@ module.exports = {
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
+ // https://eslint.org/docs/rules/jsx-quotes
'jsx-quotes': ['off', 'prefer-double'],
// enforces spacing between keys and values in object literal properties
@@ -98,7 +165,7 @@ module.exports = {
}],
// enforce position of line comments
- // http://eslint.org/docs/rules/line-comment-position
+ // https://eslint.org/docs/rules/line-comment-position
// TODO: enable?
'line-comment-position': ['off', {
position: 'above',
@@ -107,24 +174,35 @@ module.exports = {
}],
// disallow mixed 'LF' and 'CRLF' as linebreaks
- // http://eslint.org/docs/rules/linebreak-style
+ // 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': 'off',
// require or disallow newlines around directives
- // http://eslint.org/docs/rules/lines-around-directive
+ // https://eslint.org/docs/rules/lines-around-directive
'lines-around-directive': ['error', {
before: 'always',
after: 'always',
}],
+ // Require or disallow logical assignment logical operator shorthand
+ // https://eslint.org/docs/latest/rules/logical-assignment-operators
+ // TODO, semver-major: enable
+ 'logical-assignment-operators': ['off', 'always', {
+ enforceForIfStatements: true,
+ }],
+
// specify the maximum depth that blocks can be nested
'max-depth': ['off', 4],
// specify the maximum length of a line in your program
- // http://eslint.org/docs/rules/max-len
+ // https://eslint.org/docs/rules/max-len
'max-len': ['error', 100, 2, {
ignoreUrls: true,
ignoreComments: false,
@@ -134,13 +212,22 @@ module.exports = {
}],
// specify the max number of lines in a file
- // http://eslint.org/docs/rules/max-lines
+ // 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': 'off',
@@ -151,11 +238,15 @@ module.exports = {
'max-statements': ['off', 10],
// restrict the number of statements per line
- // http://eslint.org/docs/rules/max-statements-per-line
+ // 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
+ // https://eslint.org/docs/rules/multiline-ternary
// TODO: enable?
'multiline-ternary': ['off', 'never'],
@@ -168,47 +259,53 @@ module.exports = {
}],
// disallow the omission of parentheses when invoking a constructor with no arguments
- // http://eslint.org/docs/rules/new-parens
+ // https://eslint.org/docs/rules/new-parens
'new-parens': 'error',
// allow/disallow an empty newline after var statement
'newline-after-var': 'off',
- // http://eslint.org/docs/rules/newline-before-return
+ // 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
+ // 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': 'error',
// disallow use of bitwise operators
- // http://eslint.org/docs/rules/no-bitwise
+ // https://eslint.org/docs/rules/no-bitwise
'no-bitwise': 'error',
// disallow use of the continue statement
- // http://eslint.org/docs/rules/no-continue
+ // https://eslint.org/docs/rules/no-continue
'no-continue': 'error',
// disallow comments inline after code
'no-inline-comments': 'off',
// disallow if as the only statement in an else block
- // http://eslint.org/docs/rules/no-lonely-if
+ // 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
+ // https://eslint.org/docs/rules/no-mixed-operators
'no-mixed-operators': ['error', {
+ // the list of arithmetic groups disallows mixing `%` and `**`
+ // with other arithmetic operators.
groups: [
- ['+', '-', '*', '/', '%', '**'],
- ['&', '|', '^', '~', '<<', '>>', '>>>'],
- ['==', '!=', '===', '!==', '>', '>=', '<', '<='],
+ ['%', '**'],
+ ['%', '+'],
+ ['%', '-'],
+ ['%', '*'],
+ ['%', '/'],
+ ['/', '*'],
+ ['&', '|', '<<', '>>', '>>>'],
+ ['==', '!=', '===', '!=='],
['&&', '||'],
- ['in', 'instanceof']
],
allowSamePrecedence: false
}],
@@ -216,11 +313,16 @@ module.exports = {
// disallow mixed spaces and tabs for indentation
'no-mixed-spaces-and-tabs': 'error',
- // disallow multiple empty lines and only one newline at the end
- 'no-multiple-empty-lines': ['error', { 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
+ // https://eslint.org/docs/rules/no-negated-condition
'no-negated-condition': 'off',
// disallow nested ternary expressions
@@ -230,21 +332,34 @@ module.exports = {
'no-new-object': 'error',
// disallow use of unary operators, ++ and --
- // http://eslint.org/docs/rules/no-plusplus
+ // 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': [
'error',
- 'ForInStatement',
- 'ForOfStatement',
- 'LabeledStatement',
- 'WithStatement',
+ {
+ 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': 'error',
+ // deprecated in favor of func-call-spacing
+ 'no-spaced-func': 'off',
// disallow tab characters entirely
'no-tabs': 'error',
@@ -253,63 +368,96 @@ module.exports = {
'no-ternary': 'off',
// disallow trailing whitespace at the end of lines
- 'no-trailing-spaces': 'error',
+ 'no-trailing-spaces': ['error', {
+ skipBlankLines: false,
+ ignoreComments: false,
+ }],
// disallow dangling underscores in identifiers
- 'no-underscore-dangle': ['error', { 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
+ // 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
+ // 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': ['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': ['off', {
- 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
+ // https://eslint.org/docs/rules/object-property-newline
'object-property-newline': ['error', {
- allowMultiplePropertiesPerLine: true,
+ allowAllPropertiesOnSameLine: true,
}],
// allow just one var statement per function
'one-var': ['error', 'never'],
// require a newline around variable declaration
- // http://eslint.org/docs/rules/one-var-declaration-per-line
+ // 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
+ // https://eslint.org/docs/rules/operator-assignment
'operator-assignment': ['error', 'always'],
- // enforce operators to be placed before or after line breaks
- 'operator-linebreak': 'off',
+ // Requires operator at the beginning of the line in multiline statements
+ // https://eslint.org/docs/rules/operator-linebreak
+ 'operator-linebreak': ['error', 'before', { overrides: { '=': 'none' } }],
+
+ // 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
+ 'prefer-exponentiation-operator': 'error',
- // enforce padding within blocks
- 'padded-blocks': ['error', 'never'],
+ // 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
+ // 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: ['error', 'single', { avoidEscape: true }],
// do not require jsdoc
- // http://eslint.org/docs/rules/require-jsdoc
+ // https://eslint.org/docs/rules/require-jsdoc
'require-jsdoc': 'off',
// require or disallow use of semicolons instead of ASI
@@ -318,6 +466,10 @@ module.exports = {
// enforce spacing before and after semicolons
'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 }],
@@ -328,7 +480,7 @@ module.exports = {
'space-before-blocks': 'error',
// require or disallow space before function opening parenthesis
- // http://eslint.org/docs/rules/space-before-function-paren
+ // https://eslint.org/docs/rules/space-before-function-paren
'space-before-function-paren': ['error', {
anonymous: 'always',
named: 'never',
@@ -342,7 +494,7 @@ module.exports = {
'space-infix-ops': 'error',
// Require or disallow spaces before/after unary operators
- // http://eslint.org/docs/rules/space-unary-ops
+ // https://eslint.org/docs/rules/space-unary-ops
'space-unary-ops': ['error', {
words: true,
nonwords: false,
@@ -351,22 +503,29 @@ module.exports = {
}],
// require or disallow a space immediately following the // or /* in a comment
- // http://eslint.org/docs/rules/spaced-comment
- // TODO: semver-major: set balanced to "false"
+ // https://eslint.org/docs/rules/spaced-comment
'spaced-comment': ['error', 'always', {
line: {
exceptions: ['-', '+'],
- markers: ['=', '!'], // space here to support sprockets directives
+ markers: ['=', '!', '/'], // space here to support sprockets directives, slash for TS /// comments
},
block: {
exceptions: ['-', '+'],
- markers: ['=', '!'], // space here to support sprockets directives
- balanced: false,
+ 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
+ // https://eslint.org/docs/rules/unicode-bom
'unicode-bom': ['error', 'never'],
// require regex literals to be wrapped in parentheses
diff --git a/packages/eslint-config-airbnb-base/rules/variables.js b/packages/eslint-config-airbnb-base/rules/variables.js
index 8af041c082..7d61989e6a 100644
--- a/packages/eslint-config-airbnb-base/rules/variables.js
+++ b/packages/eslint-config-airbnb-base/rules/variables.js
@@ -1,3 +1,5 @@
+const confusingBrowserGlobals = require('confusing-browser-globals');
+
module.exports = {
rules: {
// enforce or disallow variable initializations at definition
@@ -10,11 +12,26 @@ module.exports = {
'no-delete-var': 'error',
// disallow labels that share a name with a variable
- // http://eslint.org/docs/rules/no-label-var
+ // https://eslint.org/docs/rules/no-label-var
'no-label-var': 'error',
// disallow specific globals
- 'no-restricted-globals': 'off',
+ 'no-restricted-globals': [
+ 'error',
+ {
+ name: 'isFinite',
+ message:
+ 'Use Number.isFinite instead https://github.com/airbnb/javascript#standard-library--isfinite',
+ },
+ {
+ name: 'isNaN',
+ message:
+ 'Use Number.isNaN instead https://github.com/airbnb/javascript#standard-library--isnan',
+ },
+ ].concat(confusingBrowserGlobals.map((g) => ({
+ name: g,
+ message: `Use window.${g} instead. https://github.com/facebook/create-react-app/blob/HEAD/packages/confusing-browser-globals/README.md`,
+ }))),
// disallow declaration of variables already declared in the outer scope
'no-shadow': 'error',
@@ -29,14 +46,14 @@ module.exports = {
'no-undef-init': 'error',
// disallow use of undefined variable
- // http://eslint.org/docs/rules/no-undefined
+ // https://eslint.org/docs/rules/no-undefined
// TODO: enable?
'no-undefined': 'off',
// disallow declaration of variables that are not used in the code
- 'no-unused-vars': ['error', { 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': 'error'
+ 'no-use-before-define': ['error', { functions: true, classes: true, variables: true }],
}
};
diff --git a/packages/eslint-config-airbnb-base/test/.eslintrc b/packages/eslint-config-airbnb-base/test/.eslintrc
index 02ab3c48bb..5808be6186 100644
--- a/packages/eslint-config-airbnb-base/test/.eslintrc
+++ b/packages/eslint-config-airbnb-base/test/.eslintrc
@@ -4,8 +4,5 @@
"no-shadow": 0,
// tests uses `t` for tape
"id-length": [2, {"min": 2, "properties": "never", "exceptions": ["t"]}],
- "import/no-extraneous-dependencies": [2, {
- "devDependencies": true
- }],
}
}
diff --git a/packages/eslint-config-airbnb-base/test/requires.js b/packages/eslint-config-airbnb-base/test/requires.js
new file mode 100644
index 0000000000..8176480fe1
--- /dev/null
+++ b/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();
+});
diff --git a/packages/eslint-config-airbnb-base/test/test-base.js b/packages/eslint-config-airbnb-base/test/test-base.js
index 810c8000b0..4380bf5567 100644
--- a/packages/eslint-config-airbnb-base/test/test-base.js
+++ b/packages/eslint-config-airbnb-base/test/test-base.js
@@ -2,13 +2,14 @@ import fs from 'fs';
import path from 'path';
import test from 'tape';
-import index from '../';
+import index from '..';
const files = { ...{ index } }; // object spread is to test parsing
-fs.readdirSync(path.join(__dirname, '../rules')).forEach((name) => {
+const rulesDir = path.join(__dirname, '../rules');
+fs.readdirSync(rulesDir).forEach((name) => {
// eslint-disable-next-line import/no-dynamic-require
- files[name] = require(`../rules/${name}`); // eslint-disable-line global-require
+ files[name] = require(path.join(rulesDir, name)); // eslint-disable-line global-require
});
Object.keys(files).forEach((
@@ -20,13 +21,13 @@ Object.keys(files).forEach((
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');
});
});
diff --git a/packages/eslint-config-airbnb-base/whitespace-async.js b/packages/eslint-config-airbnb-base/whitespace-async.js
new file mode 100755
index 0000000000..06f4f89075
--- /dev/null
+++ b/packages/eslint-config-airbnb-base/whitespace-async.js
@@ -0,0 +1,49 @@
+#!/usr/bin/env node
+
+const { isArray } = Array;
+const { entries } = Object;
+const { ESLint } = require('eslint');
+
+const baseConfig = require('.');
+const whitespaceRules = require('./whitespaceRules');
+
+const severities = ['off', 'warn', 'error'];
+
+function getSeverity(ruleConfig) {
+ if (isArray(ruleConfig)) {
+ return getSeverity(ruleConfig[0]);
+ }
+ if (typeof ruleConfig === 'number') {
+ return severities[ruleConfig];
+ }
+ return ruleConfig;
+}
+
+async function onlyErrorOnRules(rulesToError, config) {
+ const errorsOnly = { ...config };
+ const cli = new ESLint({
+ useEslintrc: false,
+ baseConfig: config
+ });
+ const baseRules = (await cli.calculateConfigForFile(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 (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;
+}
+
+onlyErrorOnRules(whitespaceRules, baseConfig).then((config) => console.log(JSON.stringify(config)));
diff --git a/packages/eslint-config-airbnb-base/whitespace.js b/packages/eslint-config-airbnb-base/whitespace.js
new file mode 100644
index 0000000000..01e5198671
--- /dev/null
+++ b/packages/eslint-config-airbnb-base/whitespace.js
@@ -0,0 +1,61 @@
+/* eslint global-require: 0 */
+
+const { isArray } = Array;
+const { entries } = Object;
+const { CLIEngine } = require('eslint');
+
+if (CLIEngine) {
+ /* eslint no-inner-declarations: 0 */
+ const whitespaceRules = require('./whitespaceRules');
+
+ const baseConfig = require('.');
+
+ const severities = ['off', 'warn', 'error'];
+
+ function getSeverity(ruleConfig) {
+ if (isArray(ruleConfig)) {
+ return getSeverity(ruleConfig[0]);
+ }
+ if (typeof ruleConfig === 'number') {
+ return severities[ruleConfig];
+ }
+ return ruleConfig;
+ }
+
+ function onlyErrorOnRules(rulesToError, config) {
+ const errorsOnly = { ...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 (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(whitespaceRules, baseConfig);
+} else {
+ const path = require('path');
+ const { execSync } = require('child_process');
+
+ // NOTE: ESLint adds runtime statistics to the output (so it's no longer JSON) if TIMING is set
+ module.exports = JSON.parse(String(execSync(path.join(__dirname, 'whitespace-async.js'), {
+ env: {
+ ...process.env,
+ TIMING: undefined,
+ }
+ })));
+}
diff --git a/packages/eslint-config-airbnb-base/whitespaceRules.js b/packages/eslint-config-airbnb-base/whitespaceRules.js
new file mode 100644
index 0000000000..6b0d3bfec7
--- /dev/null
+++ b/packages/eslint-config-airbnb-base/whitespaceRules.js
@@ -0,0 +1,49 @@
+module.exports = [
+ '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'
+];
diff --git a/packages/eslint-config-airbnb/.editorconfig b/packages/eslint-config-airbnb/.editorconfig
new file mode 120000
index 0000000000..1b3ce07def
--- /dev/null
+++ b/packages/eslint-config-airbnb/.editorconfig
@@ -0,0 +1 @@
+../../.editorconfig
\ No newline at end of file
diff --git a/packages/eslint-config-airbnb/.eslintrc b/packages/eslint-config-airbnb/.eslintrc
index 6c8556be3b..ab2c306fd9 100644
--- a/packages/eslint-config-airbnb/.eslintrc
+++ b/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,
+ },
}
diff --git a/packages/eslint-config-airbnb/.npmrc b/packages/eslint-config-airbnb/.npmrc
new file mode 120000
index 0000000000..cba44bb384
--- /dev/null
+++ b/packages/eslint-config-airbnb/.npmrc
@@ -0,0 +1 @@
+../../.npmrc
\ No newline at end of file
diff --git a/packages/eslint-config-airbnb/CHANGELOG.md b/packages/eslint-config-airbnb/CHANGELOG.md
index 4dde06abe3..68ba86b925 100644
--- a/packages/eslint-config-airbnb/CHANGELOG.md
+++ b/packages/eslint-config-airbnb/CHANGELOG.md
@@ -1,3 +1,191 @@
+19.0.4 / 2021-12-25
+==================
+ - republish to fix #2529
+
+19.0.3 / 2021-12-24
+==================
+ - [patch] set `namedComponents` option to match style guide
+ - [deps] update `eslint-plugin-react`
+
+19.0.2 / 2021-12-02
+==================
+ - [meta] fix "exports" path (#2525)
+ - [Tests] re-enable tests disabled for the eslint 8 upgrade
+
+19.0.1 / 2021-11-22
+==================
+ - [fix] `whitespace`: update to support eslint 8 (#2517)
+ - [deps] update `eslint-plugin-react`
+ - [dev deps] update `tape`
+
+19.0.0 / 2021-11-10
+==================
+ - [breaking] support `eslint` 8; drop `eslint` < 7
+ - [patch] Explain why `react/jsx-key` is turned off (#2474)
+ - [fix] bump eslint-plugin-react-hooks peer dependency version (#2356)
+ - [patch] Alphabetize the rules for react-a11y.js (#2407)
+ - [Docs] HTTP => HTTPS (#2489)
+ - [readme] clarify hooks requirement (#2482)
+ - [deps] update `eslint-config-airbnb-base`, `eslint-plugin-jsx-a11y`, `eslint-plugin-react`, `eslint-plugin-react-hooks`, `safe-publish-latest`, `eslint-plugin-import`, `object.entries`
+ - [meta] add `--no-save` to link scripts
+ - [meta] use `prepublishOnly` script for npm 7+
+ - [dev deps] update `@babel/runtime`, `tape`
+
+18.2.1 / 2020-11-06
+==================
+ - [patch] remove deprecated `jsx-a11y/accessible-emoji` rule (#2322)
+ - [patch] Fix ignoreNonDOM typo in jsx-a11y/aria-role rule (#2318)
+ - [patch] Fixed `handle` and `on` ordering in `sort-comp` rule (#2287)
+ - [deps] update `eslint-plugin-jsx-a11y`, `eslint-plugin-react`
+ - [deps] update `eslint-config-airbnb-base`, `object.assign`
+ - [dev deps] update `@babel/runtime`, `eslint-find-rules`, `eslint-plugin-import`, `eslint-plugin-jsx-a11y`, `eslint-plugin-react`
+
+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`
@@ -248,42 +436,42 @@
[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
-
-[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
-[react/display-name]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/display-name.md
-[react/jsx-no-bind]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-no-bind.md
-[react/no-is-mounted]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/no-is-mounted.md
-[react/prefer-es6-class]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-es6-class.md
-[react/jsx-quotes]: https://github.com/yannickcr/eslint-plugin-react/blob/f817e37beddddc84b4788969f07c524fa7f0823b/docs/rules/jsx-quotes.md
-[react/prefer-stateless-function]: https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/prefer-stateless-function.md
+[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/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/jsx-space-before-closing.md
+[react/sort-comp]: https://github.com/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/sort-comp.md
+[react/display-name]: https://github.com/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/display-name.md
+[react/jsx-no-bind]: https://github.com/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/jsx-no-bind.md
+[react/no-is-mounted]: https://github.com/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/no-is-mounted.md
+[react/prefer-es6-class]: https://github.com/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/prefer-es6-class.md
+[react/jsx-quotes]: https://github.com/jsx-eslint/eslint-plugin-react/blob/f817e37beddddc84b4788969f07c524fa7f0823b/docs/rules/jsx-quotes.md
+[react/prefer-stateless-function]: https://github.com/jsx-eslint/eslint-plugin-react/blob/HEAD/docs/rules/prefer-stateless-function.md
diff --git a/packages/eslint-config-airbnb/LICENSE.md b/packages/eslint-config-airbnb/LICENSE.md
new file mode 100644
index 0000000000..69d80c0252
--- /dev/null
+++ b/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.
diff --git a/packages/eslint-config-airbnb/README.md b/packages/eslint-config-airbnb/README.md
index 5014173d27..3b3f43196d 100644
--- a/packages/eslint-config-airbnb/README.md
+++ b/packages/eslint-config-airbnb/README.md
@@ -1,6 +1,6 @@
# eslint-config-airbnb
-[](http://badge.fury.io/js/eslint-config-airbnb)
+[](https://badge.fury.io/js/eslint-config-airbnb)
This package provides Airbnb's .eslintrc as an extensible shared config.
@@ -10,9 +10,27 @@ 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 most 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`. Note that it does not enable our React Hooks rules. To enable those, see the [`eslint-config-airbnb/hooks` section](#eslint-config-airbnbhooks).
+
+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 @` 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;
@@ -23,10 +41,30 @@ Our default export contains all of our ESLint rules, including ECMAScript 6+ and
Which produces and runs a command like:
```sh
- npm install --save-dev eslint-config-airbnb eslint@^#.#.# eslint-plugin-jsx-a11y@^#.#.# eslint-plugin-import@^#.#.# eslint-plugin-react@^#.#.#
+ 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
@@ -36,8 +74,8 @@ 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
diff --git a/packages/eslint-config-airbnb/hooks.js b/packages/eslint-config-airbnb/hooks.js
new file mode 100644
index 0000000000..a7f70284e3
--- /dev/null
+++ b/packages/eslint-config-airbnb/hooks.js
@@ -0,0 +1,6 @@
+module.exports = {
+ extends: [
+ './rules/react-hooks.js',
+ ].map(require.resolve),
+ rules: {}
+};
diff --git a/packages/eslint-config-airbnb/index.js b/packages/eslint-config-airbnb/index.js
index ddd3bfb712..6432e10dda 100644
--- a/packages/eslint-config-airbnb/index.js
+++ b/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),
diff --git a/packages/eslint-config-airbnb/package.json b/packages/eslint-config-airbnb/package.json
index 12c23441f6..c36359ea7c 100644
--- a/packages/eslint-config-airbnb/package.json
+++ b/packages/eslint-config-airbnb/package.json
@@ -1,15 +1,32 @@
{
"name": "eslint-config-airbnb",
- "version": "12.0.0",
+ "version": "19.0.4",
"description": "Airbnb's ESLint config, following our styleguide",
"main": "index.js",
+ "exports": {
+ ".": "./index.js",
+ "./base": "./base.js",
+ "./hooks": "./hooks.js",
+ "./legacy": "./legacy.js",
+ "./whitespace": "./whitespace.js",
+ "./rules/react": "./rules/react.js",
+ "./rules/react-a11y": "./rules/react-a11y.js",
+ "./rules/react-hooks": "./rules/react-hooks.js",
+ "./package.json": "./package.json"
+ },
"scripts": {
+ "prelint": "eclint check $(git ls-files | xargs find 2> /dev/null | grep -vE 'node_modules|\\.git')",
"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) && safe-publish-latest",
+ "prepublishOnly": "eslint-find-rules --unused && npm test && safe-publish-latest",
+ "prepublish": "not-in-publish || npm run prepublishOnly",
"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 --no-save 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 +38,11 @@
"config",
"airbnb",
"javascript",
- "styleguide"
+ "styleguide",
+ "es2015",
+ "es2016",
+ "es2017",
+ "es2018"
],
"author": "Jake Teton-Landis (https://twitter.com/@jitl)",
"contributors": [
@@ -45,28 +66,32 @@
},
"homepage": "https://github.com/airbnb/javascript",
"dependencies": {
- "eslint-config-airbnb-base": "^9.0.0"
+ "eslint-config-airbnb-base": "^15.0.0"
},
"devDependencies": {
- "babel-preset-airbnb": "^2.1.1",
- "babel-tape-runner": "^2.0.1",
- "eslint": "^3.9.0",
- "eslint-find-rules": "^1.14.3",
- "eslint-plugin-import": "^2.0.1",
- "eslint-plugin-jsx-a11y": "^2.2.3",
- "eslint-plugin-react": "^6.4.1",
- "in-publish": "^2.0.0",
+ "@babel/runtime": "^7.25.6",
+ "babel-preset-airbnb": "^4.5.0",
+ "babel-tape-runner": "^3.0.0",
+ "eclint": "^2.8.1",
+ "eslint": "^7.32.0 || ^8.2.0",
+ "eslint-find-rules": "^4.1.0",
+ "eslint-plugin-import": "^2.30.0",
+ "eslint-plugin-jsx-a11y": "^6.10.0",
+ "eslint-plugin-react": "^7.36.1",
+ "eslint-plugin-react-hooks": "^5.1.0",
+ "in-publish": "^2.0.1",
"react": ">= 0.13.0",
- "safe-publish-latest": "^1.1.1",
- "tape": "^4.6.2"
+ "safe-publish-latest": "^2.0.0",
+ "tape": "^5.9.0"
},
"peerDependencies": {
- "eslint": "^3.9.0",
- "eslint-plugin-jsx-a11y": "^2.2.3",
- "eslint-plugin-import": "^2.0.1",
- "eslint-plugin-react": "^6.4.1"
+ "eslint": "^7.32.0 || ^8.2.0",
+ "eslint-plugin-import": "^2.30.0",
+ "eslint-plugin-jsx-a11y": "^6.10.0",
+ "eslint-plugin-react": "^7.36.1",
+ "eslint-plugin-react-hooks": "^5.1.0"
},
"engines": {
- "node": ">= 4"
+ "node": "^10.12.0 || ^12.22.0 || ^14.17.0 || >=16.0.0"
}
}
diff --git a/packages/eslint-config-airbnb/rules/react-a11y.js b/packages/eslint-config-airbnb/rules/react-a11y.js
index 1df39103ab..58065120a4 100644
--- a/packages/eslint-config-airbnb/rules/react-a11y.js
+++ b/packages/eslint-config-airbnb/rules/react-a11y.js
@@ -3,110 +3,267 @@ module.exports = {
'jsx-a11y',
'react'
],
- ecmaFeatures: {
- jsx: true
+
+ parserOptions: {
+ ecmaFeatures: {
+ jsx: true,
+ },
},
+
rules: {
+ // ensure emoji are accessible
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/accessible-emoji.md
+ // disabled; rule is deprecated
+ 'jsx-a11y/accessible-emoji': 'off',
+
+ // Enforce that all elements that require alternative text have meaningful information
+ // https://github.com/jsx-eslint/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"]': [],
+ }],
+
// 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', ['']],
+ // https://github.com/jsx-eslint/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': 'error',
+ // ensure tags are valid
+ // https://github.com/jsx-eslint/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'],
+ }],
+
+ // elements with aria-activedescendant must be tabbable
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-activedescendant-has-tabindex.md
+ 'jsx-a11y/aria-activedescendant-has-tabindex': 'error',
// Enforce all aria-* props are valid.
- // https://github.com/evcohen/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-props.md
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-props.md
'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
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-proptypes.md
'jsx-a11y/aria-proptypes': 'error',
+ // Require ARIA roles to be valid and non-abstract
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-role.md
+ 'jsx-a11y/aria-role': ['error', { ignoreNonDOM: false }],
+
// 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
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/aria-unsupported-elements.md
'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': ['error', ['a']],
+ // 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: [],
+ }],
+
+ // require onClick be accompanied by onKeyUp/onKeyDown/onKeyPress
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/click-events-have-key-events.md
+ 'jsx-a11y/click-events-have-key-events': 'error',
+
+ // Enforce that a control (an interactive element) has a text label.
+ // https://github.com/jsx-eslint/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 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': 'error',
+ // ensure tags have content and are not aria-hidden
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/heading-has-content.md
+ 'jsx-a11y/heading-has-content': ['error', { components: [''] }],
+
+ // require HTML elements to have a "lang" prop
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/html-has-lang.md
+ 'jsx-a11y/html-has-lang': 'error',
+
+ // ensure iframe elements have a unique title
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/iframe-has-title.md
+ 'jsx-a11y/iframe-has-title': 'error',
// 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
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/img-redundant-alt.md
'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': ['error', ['label']],
+ // Elements with an interactive role and interaction handlers must be focusable
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/interactive-supports-focus.md
+ 'jsx-a11y/interactive-supports-focus': 'error',
+
+ // Enforce that a label tag has a text label and an associated control.
+ // https://github.com/jsx-eslint/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
+ }],
+
+ // require HTML element's lang prop to be valid
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/lang.md
+ 'jsx-a11y/lang': 'error',
+
+ // media elements must have captions
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/media-has-caption.md
+ 'jsx-a11y/media-has-caption': ['error', {
+ audio: [],
+ video: [],
+ track: [],
+ }],
// 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': 'off',
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/mouse-events-have-key-events.md
+ '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
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-access-key.md
'jsx-a11y/no-access-key': 'error',
+ // prohibit autoFocus prop
+ // https://github.com/jsx-eslint/eslint-plugin-jsx-a11y/blob/master/docs/rules/no-autofocus.md
+ 'jsx-a11y/no-autofocus': ['error', { ignoreNonDOM: true }],
+
+ // prevent distracting elements, like