EOX ESLint & Prettier config for JS projects

About

This reusable config aims to be our default way of setting up linting and formatting for JS projects. It includes:

• eslint dependency
• prettier dependency
• typescript dependency
• recommended eslint config
• recommended typescript-eslint
• typescript-eslint parser
• vue-eslint parser
• cypress rules
• chai friendly errors

The config also includes a minimal set of rules, defined in index.js.

Installation

npm install --save-dev @eox/eslint-config

Usage

Prettier

To run prettier and format all your files in the current folder, use

npx prettier --write .
or
npx prettier --write "**/*"

Please refer to the Prettier CLI docs for further details.

ESLint

To include ESLint in the project, create a file called eslint.config.mjs in the app root:

import eox from "@eox/eslint-config";

export default [...eox];

Finally, to run ESLint with auto-fixing, use

npx eslint --fix .

Please refer to the ESLint configuration docs and ESLint CLI docs for further details.

TypeScript

To use typescript checks, create a tsconfig.json in the project root

{
  "compilerOptions": {
    "allowJs": true,
    "checkJs": true,
    ...
  }
}

and run the check with

npx tsc

Ignoring files

not any longer -> only for prettier?

You can add a .prettierignore file to ignore certain folders or files/patterns.

E.g.:

public
dist
*.min.js
*.bundle.js

# adapt according to your project needs

For ESlint, use the ignores property in the config file. Example:

  // other config
  { ignores: ["dist"] },
  // other config

Custom configuration & rules

Both Prettier and ESLint allow for some rule customization. Please check the Prettier configuration options and the ESLint rules for an explanation of rules that could be added/modified to this file for individual projects.

BUT: please consider if this is really necessary, or if it could be included in the centralized config rather than in an individual project. Ideally, the individual projects should not use any custom rules.

Extend with plugins

Example: Cypress & Vue

// eslint.config.js
import eox from "@eox/eslint-config";
import pluginCypress from "eslint-plugin-cypress/flat";
import pluginVue from "eslint-plugin-vue";

export default [
  ...eox,
  pluginCypress.configs.recommended,
  ...pluginVue.configs["flat/recommended"],
  {
    rules: {
      // override/add rules settings here
    },
  },
];

Checking for valid code

To check if your code is valid before committing or inside a CI pipeline, use

npx prettier --check .
npx eslint .

Automation in VS Code (extension, settings)

Prettier

Although you can use prettier via command line, in a pre-commit hook or in a CI pipeline, you can also use the VS Code extension to format files (or file sections) via a handy command or even automatically (e.g. on file save) right inside your code editor.

--> Prettier - Code formatter extension

Please refer to the description about setting up and using the extension!

As a bare minimum, create a .prettierrc.json file in the app root to let the editor know prettier is used in this project

echo {} > .prettierrc.json

ESLint

As for ESLint, automatically running and fixing your code can be obtained by changing the settings in your workspace or dev container settings, e.g.:

"editor.codeActionsOnSave": {
  "source.fixAll.eslint": true
},