Standard

JavaScript Style Guide, with linter & automatic code fixer

Linter

standard/standard standardjs.com standard

README

JavaScript Standard Style

JavaScript style guide, linter, and formatter

This module saves you (and others!) time in three ways:

- No configuration. The easiest way to enforce code quality in your

project. No decisions to make. No .eslintrc files to manage. It just works.

- Automatically format code. Just run standard --fix and say goodbye to

messy or inconsistent code.

- Catch style issues & programmer errors early. Save precious code review

time by eliminating back-and-forth between reviewer & contributor.

Give it a try by running npx standard --fix right now!

- Quick start

- Install

- Usage

- What you might do if you're clever

- FAQ

- Why should I use JavaScript Standard Style?

- Who uses JavaScript Standard Style?

- Are there text editor plugins?

- Is there a readme badge?

- I disagree with rule X, can you change it?

- But this isn't a real web standard!

- Is there an automatic formatter?

- How do I ignore files?

- How do I disable a rule?

- I use a library that pollutes the global namespace. How do I prevent "variable is not defined" errors?

- How do I use experimental JavaScript (ES Next) features?

- Can I use a JavaScript language variant, like Flow or TypeScript?

- What about Mocha, Jest, Jasmine, QUnit, etc?

- What about Web Workers and Service Workers?

- What is the difference between warnings and errors?

- Can I check code inside of Markdown or HTML files?

- [Is there a Git pre-commit hook?](#is-there-a-git-pre-commit-hook)

- How do I make the output all colorful and pretty?

- Is there a Node.js API?

- How do I contribute to StandardJS?

Install

The easiest way to use JavaScript Standard Style is to install it globally as a

Node command line program. Run the following command in Terminal:

``` sh
$ npm install standard --global
```

Or, you can install standard locally, for use in a single project:

``` sh
$ npm install standard --save-dev
```

Note: To run the preceding commands, Node.js and npm must be installed.

Usage

After you've installed standard, you should be able to use the standard program. The

simplest use case would be checking the style of all JavaScript files in the

current working directory:

``` sh
$ standard
Error: Use JavaScript Standard Style
lib/torrent.js:950:11: Expected '===' and instead saw '=='.
```

If you've installed standard locally, run with npx instead:

``` sh
$ npx standard
```

You can optionally pass in a directory (or directories) using the glob pattern. Be

sure to quote paths containing glob patterns so that they are expanded by

standard instead of your shell:

``` sh
$ standard "src/util/**/*.js" "test/**/*.js"
```

Note: by default standard will look for all files matching the patterns:

`*/.js, */.jsx`.

What you might do if you're clever

1. Add it to package.json

``` json
{
"name": "my-cool-package",
"devDependencies": {
"standard": "*"
},
"scripts": {
"test": "standard && node my-tests.js"
}
}
```

2. Style is checked automatically when you run npm test

``` sh
$ npm test
Error: Use JavaScript Standard Style
lib/torrent.js:950:11: Expected '===' and instead saw '=='.
```

3. Never give style feedback on a pull request again!

Why should I use JavaScript Standard Style?

The beauty of JavaScript Standard Style is that it's simple. No one wants to

maintain multiple hundred-line style configuration files for every module/project

they work on. Enough of this madness!

This module saves you (and others!) time in three ways:

- No configuration. The easiest way to enforce consistent style in your

project. Just drop it in.

- Automatically format code. Just run standard --fix and say goodbye to

messy or inconsistent code.

- Catch style issues & programmer errors early. Save precious code review

time by eliminating back-and-forth between reviewer & contributor.

Adopting standard style means ranking the importance of code clarity and

community conventions higher than personal style. This might not make sense for

100% of projects and development cultures, however open source can be a hostile

place for newbies. Setting up clear, automated contributor expectations makes a

project healthier.

For more info, see the conference talk ["Write Perfect Code with Standard and

ESLint"](https://www.youtube.com/watch?v=kuHfMw8j4xk). In this talk, you'll learn

about linting, when to use standard versus eslint, and how prettier compares

to standard.

Who uses JavaScript Standard Style?

[	[	[
\|---\|---\|---\|---\|

[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	[	[	[
\|---\|---\|---\|---\|

[	Your	\|
\|---\|---\|---\|---\|

In addition to companies, many community members use standard on packages that

are too numerous

to list here.

standard is also the top-starred linter in GitHub's

Clean Code Linter showcase.

Are there text editor plugins?

First, install standard. Then, install the appropriate plugin for your editor:

Sublime Text

Using [Package Control][sublime-1], install [SublimeLinter][sublime-2] and

[SublimeLinter-contrib-standard][sublime-3].

For automatic formatting on save, install [StandardFormat][sublime-4].

[sublime-1]: https://packagecontrol.io/

[sublime-2]: http://www.sublimelinter.com/en/latest/

[sublime-3]: https://packagecontrol.io/packages/SublimeLinter-contrib-standard

[sublime-4]: https://packagecontrol.io/packages/StandardFormat

Atom

Install [linter-js-standard][atom-1].

Alternatively, you can install [linter-js-standard-engine][atom-4]. Instead of

bundling a version of standard it will automatically use the version installed

in your current project. It will also work out of the box with other linters based

on [standard-engine][atom-5].

For automatic formatting, install [standard-formatter][atom-2]. For snippets,

install [standardjs-snippets][atom-3].

[atom-1]: https://atom.io/packages/linter-js-standard

[atom-2]: https://atom.io/packages/standard-formatter

[atom-3]: https://atom.io/packages/standardjs-snippets

[atom-4]: https://atom.io/packages/linter-js-standard-engine

[atom-5]: https://github.com/standard/standard-engine

Visual Studio Code

Install [vscode-standard][vscode-1]. (Includes support for automatic formatting.)

For JS snippets, install: [vscode-standardjs-snippets][vscode-2]. For React snippets, install [vscode-react-standard][vscode-3].

[vscode-1]: https://marketplace.visualstudio.com/items?itemName=standard.vscode-standard

[vscode-2]: https://marketplace.visualstudio.com/items?itemName=capaj.vscode-standardjs-snippets

[vscode-3]: https://marketplace.visualstudio.com/items?itemName=TimonVS.ReactSnippetsStandard

Vim

Install [ale][vim-1]. And add these lines to your .vimrc file.

```vim
let g:ale_linters = {
\ 'javascript': ['standard'],
\}
let g:ale_fixers = {'javascript': ['standard']}
```

This sets standard as your only linter and fixer for javascript files and so prevents conflicts with eslint. For linting and automatic fixing on save, add these lines to .vimrc:

```vim
let g:ale_lint_on_save = 1
let g:ale_fix_on_save = 1
```

Alternative plugins to consider include [neomake][vim-2] and [syntastic][vim-3], both of which have built-in support for standard (though configuration may be necessary).

[vim-1]: https://github.com/w0rp/ale

[vim-2]: https://github.com/neomake/neomake

[vim-3]: https://github.com/vim-syntastic/syntastic

Emacs

Install [Flycheck][emacs-1] and check out the [manual][emacs-2] to learn

how to enable it in your projects.

[emacs-1]: http://www.flycheck.org

[emacs-2]: http://www.flycheck.org/en/latest/user/installation.html

Brackets

Search the extension registry for ["Standard Code Style"][brackets-1] and click "Install".

[brackets-1]: https://github.com/ishamf/brackets-standard/

WebStorm (PhpStorm, IntelliJ, RubyMine, JetBrains, etc.)

WebStorm recently announced native support

for standard directly in the IDE.

If you still prefer to configure standard manually, [follow this guide][webstorm-1]. This applies to all JetBrains products, including PhpStorm, IntelliJ, RubyMine, etc.

[webstorm-1]: docs/webstorm.md

Is there a readme badge?

Yes! If you use standard in your project, you can include one of these badges in

your readme to let people know that your code is using the standard style.

```md [![JavaScript Style Guide](https://cdn.rawgit.com/standard/standard/master/badge.svg)](https://github.com/standard/standard)
```

```md [![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
```

I disagree with rule X, can you change it?

No. The whole point of standard is to save you time by avoiding

[bikeshedding][bikeshedding] about code style. There are lots of debates online about

tabs vs. spaces, etc. that will never be resolved. These debates just distract from

getting stuff done. At the end of the day you have to 'just pick something', and

that's the whole philosophy of standard -- its a bunch of sensible 'just pick

something' opinions. Hopefully, users see the value in that over defending their

own opinions.

There are a couple of similar packages for anyone who does not want to completely accept standard:

- semistandard - standard, with semicolons

- standardx - standard, with custom tweaks

If you really want to configure hundreds of ESLint rules individually, you can

always use eslint directly with

eslint-config-standard to

layer your changes on top.

[standard-eject](https://github.com/josephfrazier/standard-eject) can help

you migrate from standard to eslint and eslint-config-standard.

Pro tip: Just use standard and move on. There are actual real problems that you

could spend your time solving! :P

[bikeshedding]: https://docs.freebsd.org/en/books/faq/#bikeshed-painting

But this isn't a real web standard!

Of course it's not! The style laid out here is not affiliated with any official web

standards groups, which is why this repo is called standard/standard and not

ECMA/standard.

The word "standard" has more meanings than just "web standard" :-) For example:

- This module helps hold our code to a high standard of quality.

- This module ensures that new contributors follow some basic style standards.

Is there an automatic formatter?

Yes! You can use standard --fix to fix most issues automatically.

standard --fix is built into standard for maximum convenience. Most problems

are fixable, but some errors (like forgetting to handle errors) must be fixed

manually.

To save you time, standard outputs the message "`Run standard --fix to

automatically fix some problems`" when it detects problems that can be fixed

automatically.

How do I ignore files?

Certain paths (node_modules/, coverage/, vendor/, *.min.js,

and files/folders that begin with . like .git/) are automatically ignored.

Paths in a project's root .gitignore file are also automatically ignored.

Sometimes you need to ignore additional folders or specific minified files. To do

that, add a standard.ignore property to package.json:

``` json
"standard": {
"ignore": [
"**/out/",
"/lib/select2/",
"/lib/ckeditor/",
"tmp.js"
]
}
```

How do I disable a rule?

In rare cases, you'll need to break a rule and hide the error generated by

standard.

JavaScript Standard Style uses ESLint under-the-hood and

you can hide errors as you normally would if you used ESLint directly.

Disable all rules on a specific line:

``` js
file = 'I know what I am doing' // eslint-disable-line
```

Or, disable only the "no-use-before-define" rule:

``` js
file = 'I know what I am doing' // eslint-disable-line no-use-before-define
```

Or, disable the "no-use-before-define" rule for multiple lines:

``` js
/* eslint-disable no-use-before-define */
console.log('offending code goes here...')
console.log('offending code goes here...')
console.log('offending code goes here...')
/* eslint-enable no-use-before-define */
```

I use a library that pollutes the global namespace. How do I prevent "variable is not defined" errors?

Some packages (e.g. mocha) put their functions (e.g. describe, it) on the

global object (poor form!). Since these functions are not defined or require'd

anywhere in your code, standard will warn that you're using a variable that is

not defined (usually, this rule is really useful for catching typos!). But we want

to disable it for these global variables.

To let standard (as well as humans reading your code) know that certain variables

are global in your code, add this to the top of your file:

``` js
/* global myVar1, myVar2 */
```

If you have hundreds of files, it may be desirable to avoid adding comments to

every file. In this case, run:

``` sh
$ standard --global myVar1 --global myVar2
```

Or, add this to package.json:

``` json
{
"standard": {
"globals": [ "myVar1", "myVar2" ]
}
}
```

Note: global and globals are equivalent.

How do I use experimental JavaScript (ES Next) features?

standard supports the latest ECMAScript features, ES8 (ES2017), including

language feature proposals that are in "Stage 4" of the proposal process.

To support experimental language features, standard supports specifying a

custom JavaScript parser. Before using a custom parser, consider whether the added

complexity is worth it.

To use a custom parser, first install it from npm:

``` sh
npm install @babel/eslint-parser --save-dev
```

Then run:

``` sh
$ standard --parser @babel/eslint-parser
```

Or, add this to package.json:

``` json
{
"standard": {
"parser": "@babel/eslint-parser"
}
}
```

Can I use a JavaScript language variant, like Flow or TypeScript?

standard supports the latest ECMAScript features. However, Flow and TypeScript add new

syntax to the language, so they are not supported out-of-the-box.

For TypeScript, an official variant ts-standard is supported and maintained that provides a very

similar experience to standard.

For other JavaScript language variants, standard supports specifying a custom JavaScript

parser as well as an ESLint plugin to handle the changed syntax. Before using a JavaScript

language variant, consider whether the added complexity is worth it.

TypeScript

[ts-standard](https://github.com/standard/ts-standard) is the officially supported variant for

TypeScript. ts-standard supports all the same rules and options as standard and includes

additional TypeScript specific rules. ts-standard will even lint regular javascript files

by setting the configuration in tsconfig.json.

``` sh
npm install ts-standard --save-dev
```

Then run (where tsconfig.json is located in the working directory):

``` sh
$ ts-standard
```

Or, add this to package.json:

``` json
{
"ts-standard": {
"project": "./tsconfig.json"
}
}
```

Note: To include additional files in linting such as test files, create a tsconfig.eslint.json file to use instead.

If you really want to configure hundreds of ESLint rules individually, you can always use eslint

directly with [eslint-config-standard-with-typescript](https://github.com/standard/eslint-config-standard-with-typescript)

to layer your changes on top.

Flow

To use Flow, you need to run standard with @babel/eslint-parser as the parser and

eslint-plugin-flowtype as a plugin.

``` sh
npm install @babel/eslint-parser eslint-plugin-flowtype --save-dev
```

Then run:

``` sh
$ standard --parser @babel/eslint-parser --plugin flowtype
```

Or, add this to package.json:

``` json
{
"standard": {
"parser": "@babel/eslint-parser",
"plugins": [ "flowtype" ]
}
}
```

Note: plugin and plugins are equivalent.

What about Mocha, Jest, Jasmine, QUnit, etc?

To support mocha in test files, add this to the top of the test files:

``` js
/* eslint-env mocha */
```

Or, run:

``` sh
$ standard --env mocha
```

Where mocha can be one of jest, jasmine, qunit, phantomjs, and so on. To see a

full list, check ESLint's

specifying environments

documentation. For a list of what globals are available for these environments,

check the

globals npm

module.

Note: env and envs are equivalent.

What about Web Workers and Service Workers?

Add this to the top of web worker files:

``` js
/* eslint-env worker */
```

This lets standard (as well as humans reading the code) know that self is a

global in web worker code.

For Service workers, add this instead:

``` js
/* eslint-env serviceworker */
```

What is the difference between warnings and errors?

standard treats all rule violations as errors, which means that standard

will exit with a non-zero (error) exit code.

However, we may occasionally release a new major version of standard

which changes a rule that affects the majority of standard users (for example,

transitioning from var to let/const). We do this only when we think the

advantage is worth the cost and only when the rule is

auto-fixable.

In these situations, we have a "transition period" where the rule change is only

a "warning". Warnings don't cause standard to return a non-zero (error)

exit code. However, a warning message will still print to the console. During

the transition period, using standard --fix will update your code so that it's

ready for the next major version.

The slow and careful approach is what we strive for with standard. We're

generally extremely conservative in enforcing the usage of new language

features. We want using standard to be light and fun and so we're careful

about making changes that may get in your way. As always, you can

disable a rule at any time, if necessary.

Can I check code inside of Markdown or HTML files?

To check code inside Markdown files, use [standard-markdown](https://www.npmjs.com/package/standard-markdown).

Alternatively, there are ESLint plugins that can check code inside Markdown, HTML,

and many other types of language files:

To check code inside Markdown files, use an ESLint plugin:

``` sh
$ npm install eslint-plugin-markdown
```

Then, to check JS that appears inside code blocks, run:

``` sh
$ standard --plugin markdown '**/*.md'
```

To check code inside HTML files, use an ESLint plugin:

``` sh
$ npm install eslint-plugin-html
```

Then, to check JS that appears inside `

Standard

README

JavaScript Standard Style

Sponsored by

JavaScript style guide, linter, and formatter

Table of Contents

Install

Usage

What you might do if you're clever

Why should I use JavaScript Standard Style?

Who uses JavaScript Standard Style?

Are there text editor plugins?

Sublime Text

Atom

Visual Studio Code

Vim

Emacs

Brackets

WebStorm (PhpStorm, IntelliJ, RubyMine, JetBrains, etc.)

Is there a readme badge?

I disagree with rule X, can you change it?

But this isn't a real web standard!

Is there an automatic formatter?

How do I ignore files?

How do I disable a rule?

I use a library that pollutes the global namespace. How do I prevent "variable is not defined" errors?

How do I use experimental JavaScript (ES Next) features?

Can I use a JavaScript language variant, like Flow or TypeScript?

TypeScript

Flow

What about Mocha, Jest, Jasmine, QUnit, etc?

What about Web Workers and Service Workers?

What is the difference between warnings and errors?

Can I check code inside of Markdown or HTML files?