eslint_d

Makes eslint the fastest linter on the planet.

"But eslint is pretty fast already, right?"

Yes, it's actually super fast. But the node.js startup time and loading all the required modules slows down linting times for a single file to ~700 milliseconds. eslint_d reduces this overhead by running a server in the background. It brings the linting time down to ~160 milliseconds. If you want to lint from within your editor whenever you save a file, eslint_d is for you.

Install

This will install the eslint_d command globally:

$ npm install -g eslint_d

Usage

To start the server and lint a file, just run:

$ eslint_d file.js

On the initial call, the eslint_d server is launched and then the given file is linted. Subsequent invocations are super fast.

Commands

Control the server like this:

$ eslint_d <command>

Available commands:

• start: start the server
• stop: stop the server
• status: print out whether the server is currently running
• restart: restart the server
• [options] file.js [file.js] [dir]: invoke eslint with the given options. The eslint engine will be created in the current directory. If the server is not yet running, it is started.

Type eslint_d --help to see the supported eslint options.

eslint_d will select a free port automatically and store the port number along with an access token in ~/.eslint_d.

Editor integration

• Sublime: Check out SublimeLinter-contrib-eslint_d.

• Vim: Install the syntastic plugin, then make sure this is in your .vimrc:

  let g:syntastic_javascript_checkers = ['eslint']
  let g:syntastic_javascript_eslint_exec = 'eslint_d'

• WebStorm: Configure your IDE to point to the eslint_d package instead of eslint. In the ESLint configuration dialog, under 'ESLint package', select your eslint_d package.

• Atom: You will not gain any performance from this module as it already avoids starting a new node instance and uses the API directly (see this AtomLinter issue).

• Emacs: Use flycheck with the javascript-eslint checker:

  (setq flycheck-javascript-eslint-executable "eslint_d")

If you're using eslint_d in any other editor, please tell me!

Moar speed

If you're really into performance and want the lowest possible latency, talk to the eslint_d server with netcat. This will also eliminate the node.js startup time.

$ PORT=`cat ~/.eslint_d | cut -d" " -f1`
$ TOKEN=`cat ~/.eslint_d | cut -d" " -f2`
$ echo "$TOKEN $PWD file.js" | nc localhost $PORT

This runs eslint in under 50ms!

Tip For additional speed, did you know that you can lint only files that have changed? This is a feature of normal eslint, but it also works from eslint_d. Run:

$ eslint_d . --cache

Refresh .eslintrc

eslint_d runs serperate instances of eslint each working directory, (see here) for more details.

However should the .eslintrc change after the server has already been started, you can manually reload the configuration by running eslint_d restart in the working directory.

Compatibility

• 4.0.0: eslint 3.0+
• 3.0.0: eslint 2.2+
• 1.0.0, 2.0.0: eslint 1.4+

License

MIT