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esprint - a fast eslint runner GitHub Workflow Status npm version

esprint (pronounced E-S-sprint) speeds up eslint by running the linting engine across multiple threads. esprint sets up a server daemon to cache the lint status of each file in memory. It uses a watcher to determine when files change, to only lint files as necessary. It also has a CI mode where it does not set up a daemon and just lints in parallel.


In order to use esprint, first place an .esprintrc file in the root directory your project. This is similar to a .flowconfig if you use flow types. The .esprintrc file describes which paths to lint and which paths to ignore. You can also override the port to start the background server on. A sample .esprintrc file:

  "paths": ["foo/*.js", "bar/**/*.js"],
  "ignored": ["**/node_modules/**/*"],
  "port": 5004


Name Type Description
paths {Array<String>} Glob-style paths for files to include when linting
ignored {Array<String>} Glob-style paths to ignore (not watch) during dev mode for better performance (.eslintignore applies as normal)
port {Number} (optional) Run the esprint background server on a specific port
formatter {string} (optional) Use a specific output format - default: stylish
quiet {boolean} (optional) Report errors only - default: false
maxWarnings {number} (optional) The max number of warnings that should trigger a failure. The default is to not fail on warnings


Default mode

To run esprint, use the following command anywhere in your project:


esprint will find the root of your project automatically and lint the whole project. In default mode, esprint will start a background server to watch source files and cache lint results in memory.

By default, esprint will split up linting duties across all CPUs in your machine. You can manually override this via the cli with the following argument:

esprint --workers=[num_workers]

To kill the esprint server in the background & clear the cache, use the following command:

esprint stop

You can run esprint from any subdirectory that .esprintrc is located in, and it will still properly lint all files as specified.

CI Mode

In CI environments, it is not always appropriate (or necessary) to start a background server. In this case, you can use the following command, which simply lints in parallel without setting up a background server:

esprint check

CLI Options

Auto fix

To use the eslint auto fix feature, add --fix when starting the server

esprint --fix

or when running in CI mode

esprint check --fix


Print debug output for esprint. Should only be used when you're running into issues

esprint --esprintDebug

Disable watchman

esprint --noWatchman

Developing for esprint