JavaScript Standard Style
One Style to Rule Them All
No decisions to make. No .eslintrc
, .jshintrc
, or .jscsrc
files to manage. It just
works.
This module saves you (and others!) time in two ways:
- No configuration. The easiest way to enforce consistent style in your project. Just drop it in.
- Catch style errors before they're submitted in PRs. Saves precious code review time by eliminating back-and-forth between maintainer and contributor.
Install
npm install standard
Rules
- 2 spaces – for indentation
- Single quotes for strings – except to avoid escaping
- No unused variables – this one catches tons of bugs!
- No semicolons – It's fine. Really!
- Never start a line with
(
or[
- This is the only gotcha with omitting semicolons – automatically checked for you!
- More details
- Space after keywords
if (condition) { ... }
- Space after function name
function name (arg) { ... }
- Always use
===
instead of==
– butobj == null
is allowed to checknull || undefined
. - Always handle the node.js
err
function parameter - Always prefix browser globals with
window
– exceptdocument
andnavigator
are okay- Prevents accidental use of poorly-named browser globals like
open
,length
,event
, andname
.
- Prevents accidental use of poorly-named browser globals like
- And more goodness – give
standard
a try today!
To get a better idea, take a look at
a sample file written
in JavaScript Standard Style, or check out some of
the repositories that use
standard
.
Badge
Use this in one of your projects? Include one of these badges in your readme to let people know that your code is using the standard style.
[![js-standard-style](https://cdn.rawgit.com/feross/standard/master/badge.svg)](https://github.com/feross/standard)
[![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg)](http://standardjs.com/)
Usage
The easiest way to use JavaScript Standard Style to check your code is to install it
globally as a Node command line program. To do so, simply run the following command in
your terminal (flag -g
installs standard
globally on your system, omit it if you want
to install in the current working directory):
npm install standard -g
After you've done that 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:
$ standard
Error: Use JavaScript Standard Style
lib/torrent.js:950:11: Expected '===' and instead saw '=='.
You can optionally pass in a directory using the glob pattern:
$ standard src/util/**/*.js
Note: by default standard
will look for all files matching the patterns: **/*.js
, **/*.jsx
.
Text editor plugins
First, install standard
. Then, install the appropriate plugin for your editor:
Sublime Text
Using Package Control, install SublimeLinter and SublimeLinter-contrib-standard.
For automatic formatting on save, install StandardFormat.
Atom
Install linter-js-standard.
For automatic formatting, install standard-formatter. For snippets, install atom-standardjs-snippets.
Vim
Install Syntastic and add this line to .vimrc
:
let g:syntastic_javascript_checkers = ['standard']
For automatic formatting on save, add these two lines to .vimrc
:
autocmd bufwritepost *.js silent !standard % --format
set autoread
Emacs
Install Flycheck and check out the manual to learn how to enable it in your projects.
Brackets
Search the extension registry for "Standard Code Style".
What you might do if you're clever
- Add it to
package.json
{
"name": "my-cool-package",
"devDependencies": {
"standard": "^3.0.0"
},
"scripts": {
"test": "standard && node my-tests.js"
}
}
- Check style automatically when you run
npm test
$ npm test
Error: Use JavaScript Standard Style
lib/torrent.js:950:11: Expected '===' and instead saw '=='.
- Never give style feedback on a pull request again!
FAQ
Why would 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 time in two ways:
- No configuration. The easiest way to enforce consistent style in your project. Just drop it in.
- Catch style errors before they're submitted in PRs. Saves precious code review time by eliminating back-and-forth between maintainer and 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.
I disagree with rule X, can you change it?
No. The whole point of standard
is to avoid bikeshedding about
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.
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 feross/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! Just run standard --format filename.js
. This uses
Max Ogden's automatic formatter
standard-format
, which can automatically
fix most code issues.
While most issues can be fixed, some, like not handling errors in node-style callbacks, must be fixed manually.
How do I ignore files?
The paths node_modules/**
, *.min.js
, bundle.js
, coverage/**
, hidden files/folders
(beginning with .
), and all patterns in a project's root .gitignore
file are
automatically ignored.
Sometimes you need to ignore additional folders or specific minified files. To do that, add
a standard.ignore
property to package.json
:
"standard": {
"ignore": [
"**/out/",
"/lib/select2/",
"/lib/ckeditor/",
"tmp.js"
]
}
How do I hide a certain warning?
In rare cases, you'll need to break a rule and hide the warning generated by standard
.
JavaScript Standard Style uses eslint
under-the-hood and you can
hide warnings as you normally would if you used eslint
directly.
To get verbose output (so you can find the particular rule name to ignore), run:
$ standard --verbose
Error: Use JavaScript Standard Style
routes/error.js:20:36: 'file' was used before it was defined. (no-use-before-define)
Disable all rules on a specific line:
file = 'I know what I am doing' // eslint-disable-line
Or, disable only the "no-use-before-define"
rule:
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:
/*eslint-disable no-use-before-define */
// offending code here...
// offending code here...
// offending code 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:
/* global myVar1, myVar2 */
If you have hundreds of files, adding comments to every file can be tedious. In these
cases, you can add this to package.json
:
{
"standard": {
"globals": [ "myVar1", "myVar2" ]
}
}
Can I use a custom JS parser for bleeding-edge ES6 or ES7 support?
standard
supports custom JS parsers. To use a custom parser, install it from npm
(example: npm install babel-eslint
) and add this to your package.json
:
{
"standard": {
"parser": "babel-eslint"
}
}
If you're using standard
globally (you installed it with -g
), then you also need to
install babel-eslint
globally with npm install babel-eslint -g
.
Can you make rule X configurable?
No. The point of standard
is to save you time by picking reasonable rules so you can
spend your time solving actual problems. If you really do want to configure hundreds of
eslint rules individually, you can always use eslint
directly.
If you just want to tweak a couple rules, consider using this shareable config and layering your changes on top.
Pro tip: Just use standard
and move on. There are actual real problems that you could
spend your time solving! :P
What about Web Workers?
Web workers have a magic global variable called self
. In regular JS files, standard
won't let you use self
directly, as it wants to prevent accidental use of
window.self
. But standard
has no way of knowing when you are in a worker
and
therefore does not know when to allow usage of self
directly.
Until we figure out a better solution, we recommend adding this to the top of workers:
/* global self */
This lets standard
(as well as humans reading your code) know that self
is a global
in web worker code.
pre-commit
hook?
Is there a Git Funny you should ask!
#!/bin/sh
# Ensure all javascript files staged for commit pass standard code style
git diff --name-only --cached --relative | grep '\.js$' | xargs standard
exit $?
Alternatively, overcommit is a Git hook
manager that includes support for running standard
as a Git pre-commit hook.
To enable this, add the following to your .overcommit.yml
file:
PreCommit:
Standard:
enabled: true
How do I make the output all colorful and pretty?
The built-in output is simple and straightforward, but if you like shiny things, install snazzy:
npm install snazzy
And run:
$ standard --verbose | snazzy
There's also standard-tap, standard-json, and standard-reporter
standard
. What packages should I know about?
I want to contribute to - standard - this repo
- eslint - the linter that powers standard
- eslint-config-standard - eslint rules for standard
- eslint-config-standard-react - eslint rules for React and JSX
- eslint-plugin-standard - custom eslint rules for standard (not part of eslint core)
- standard-format - automatic code formatter
- standard-engine - cli engine for arbitrary eslint rules
- snazzy - pretty terminal output for standard
- semistandard - standard, with semicolons (if you must)
There are also many editor plugins and other awesome standard packages.
Node.js API
standard.lintText(text, [opts], callback)
Lint the provided source text
to enforce JavaScript Standard Style. An opts
object may
be provided:
var opts = {
globals: [], // global variables to declare
parser: '' // custom js parser (e.g. babel-eslint)
}
The callback
will be called with an Error
and results
object:
var results = {
results: [
{
filePath: '',
messages: [
{ ruleId: '', message: '', line: 0, column: 0 }
],
errorCount: 0,
warningCount: 0
}
],
errorCount: 0,
warningCount: 0
}
standard.lintFiles(files, [opts], callback)
Lint the provided files
globs. An opts
object may be provided:
var opts = {
globals: [], // global variables to declare
parser: '', // custom js parser (e.g. babel-eslint)
ignore: [], // file globs to ignore (has sane defaults)
cwd: '' // current working directory (default: process.cwd())
}
The callback
will be called with an Error
and results
object (same as above).
License
MIT. Copyright (c) Feross Aboukhadijeh.