Lint setup

TIP

Requires @compas/cli and @compas/eslint-plugin to be installed as 'devDependencies'.

The @compas/eslint-plugin package provides a Prettier config and ESLint plugin. This configuration is tailored towards Javascript projects. When using Typescript you can still use the Prettier config, however the command (compas lint) shouldn't be used. To get the configuration in your project, create the following three files:

/.eslintrc.cjs

/* eslint-disable import/no-commonjs */

module.exports = {
  extends: ["plugin:@compas/full"],
};

/.prettierrc.cjs

/* eslint-disable import/no-commonjs */

module.exports = {
  ...require("@compas/eslint-plugin/prettierrc.js"),
};

/.prettierignore

coverage/**

This way you should be able to easily override any configuration if necessary. By following the respective guides / configuration options:

Now is also a good time to set up your IDE to use your local configuration.

Running the linter

At the moment we have only configured the underlying tools but have not run anything yet. This is where @compas/cli comes in. This package also has a range of features, but for now we focus on two of them. Let's start with running the linters:

compas lint

This runs both ESLint and Prettier in auto fix mode over your Javascript files. Prettier will also look at plain JSON and Markdown files.

There is also an environment variable available that runs Prettier in 'check' mode. This way it will only report errors and not run the auto fixer. This can be enabled by setting CI=true:

export CI=true
compas lint
unset CI

Most CI runners automatically set this environment variable, so the linter will fail when code is not formatted correctly.