JavaScript Standard Style

One Style to Rule Them All

No decisions to make, no .jshintrc or .jscs files to manage. It just works.

Install

npm install standard

Rules

• 2 spaces for indentation
• Single quotes for strings
  • Except to avoid escaping like "in this lil' string"
• Unix line breaks (LF)
• No unused variables (this one catches so many bugs and typos!)
• No semicolons
  • It's totally fine. Really!
• Never start a line with ( or [
  • This is the only gotcha with omitting semicolons – automatically checked for you!
  • Always prefix with ; like this ;[1, 2, 3].join(' ')
• Spaces after keywords
  • if (condition) { ... }
• Spaces before/after function definitions
  • function name (arg1, arg2) { ... }
• Always name the context variable self
  • var self = this
  • Checks for accidental use of window.self when var self = this is omitted
• Always use === instead of ==
  • obj == null is allowed for succinctness (obj === null || obj === undefined)

To get a better idea, take a look at a sample file written in JavaScript Standard Style.

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: Code style check failed:
  lib/torrent.js:950:11: Expected '===' and instead saw '=='.

What you might do if you're clever

1. Add it to package.json

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

2. Check style automatically when you run npm test

$ npm test
Error: Code style check failed:
  lib/torrent.js:950:11: Expected '===' and instead saw '=='.

3. 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 .jshintrc and .jscs for every module/project they maintain. Enough of this madness!

This module saves you time in two ways:

• No configuration. Just drop it in. The easiest way to enforce consistent style in your module/project.
• Catch style errors before they're submitted in PRs. Saves precious code review time by eliminating back-and-forth between maintainer and contributor.

How do I ignore files?

The paths node_modules/, .git/, *.min.js, and bundle.js are automatically excluded when looking for .js files to style check.

Sometimes you need to ignore additional folders or specific minfied files. To do that, add a standard.ignore property to package.json:

"standard": {
  "ignore": [
    "**/out/**",
    "**/lib/select2/**",
    "**/lib/ckeditor/**"
  ]
}

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 jshint and jscs under-the-hood and you can hide their warnings as you normally would if you used each linter directly.

To get verbose output (so you can find the particular rule name to ignore), run:

$ standard --verbose
Error: Code style check failed:
  routes/error.js:20:36: 'next' is defined but never used. (W098)
  routes/submit.js:85:2: Expected indentation of 2 characters (validateIndentation)

The first warning is jshint (always starts with a W). You can hide it with a /* jshint -W098 */ comment. Re-enable with a /* jshint +W098 */ comment.

Example:

/* jshint -W098 */
app.use(function (err, req, res, next) {
  res.render('error', { err: err })
})
/* jshint +W098 */

The second warning is from jscs (always a long camel-case string), which you can hide with a // jscs:disable validateIndentation comment. Re-enable with a // jscs:enable validateIndentation comment.

Can you please add more config options?

No. Use jshint or jscs directly if you want that.

Pro tip: Just use standard and move on. There are actual real problems that you could spend your time solving :p

License

MIT. Copyright (c) Feross Aboukhadijeh.