Eslint and Prettier Setup

These are my settings for ESLint and Prettier

What it does

• Lints JavaScript and TypeScript based on the latest standards
• Fixes issues and formatting errors with Prettier
• Lints + Fixes inside of html script tags
• Lints + Fixes React via eslint-config-airbnb
• You can see all the rules here

Project Install

It's recommended you install this once per project. ESLint used to have global configs, but no longer.

1. If you don't already have a package.json file, create one with npm init -y.

2. Then we need to install this config

npm install @iammattburns/eslint-config

4. We need to put our eslint settings in a file in the root of your project. I prefer to use our existing package.json, and add an eslintConfig property. You can also create a new .eslintrc or .eslintrc.js file that lives where package.json does:

in package.json, add this anywhere top level. Like right under your "scripts" object.

"eslintConfig": {
  "extends": ["@iammattburns/eslint-config"]
}

Or put this in a .eslintrc file

{
  "extends": ["@iammattburns/eslint-config"]
}

For TypeScript projects, use @iammattburns/eslint-config/typescript.

{
  "extends": ["@iammattburns/eslint-config/typescript"]
}

5. You can add two scripts to your package.json to lint and/or fix:

"scripts": {
  "lint": "eslint .",
  "lint:fix": "eslint . --fix"
},

6. Now you can manually lint your code by running npm run lint and fix all fixable issues with npm run lint:fix. You probably want your editor to do this though.

TypeScript

tsconfig.json allows extensions via the extends key, but doesn't support module resolution (i.e. a node module), thus making it quite restrictive when it comes to referencing the path to a parent config file. Paths specified must be relative or absolute, absolute paths being of no use to us in the context of a shared code base.

Importing the shared config from ./node_modules/@iammattburns/eslint-config is our only option.

Single package repo

To use this config, create an tsconfig.js file in the root of your repo and add:

{
  "extends": "./node_modules/@iammattburns/eslint-config/tsconfig.json",
  ...
}

Mono repo

To use this config, create an tsconfig.js file in the root of your specific package (e.g. ./packages/?) and add:

{
  "extends": "../../node_modules/@iammattburns/eslint-config/tsconfig.json",
  ...
}

Settings

If you'd like to overwrite eslint or prettier settings, you can add the rules in your .eslintrc file. The ESLint rules go directly under "rules".

{
  "extends": [
    "@iammattburns/eslint-config"
  ],
  "rules": {
    "no-console": 2,
  }
}

Prettier Rules

There are only 2 prettier rules included in my config - singleQuote: true and endOfLine: 'auto'.

If you want custom prettier options, it's recommended to create a .prettierrc file in your root directory like so:

{
  "singleQuote": true,
  "endOfLine": "auto",
  "tabWidth": 4
}

You can also put this in your EsLint config as a rule like so:

{
  "extends": ["@iammattburns/eslint-config"],
  "rules": {
    ... any eslint rules here
    "prettier/prettier": [
      "error",
      {
        "singleQuote": true,
        "endOfLine": "auto",
        "tabWidth": 4
      },
    ],
  }
}

Note if you are switching to double quotes, you'll also need to add this eslint rule, or they will fight to the death!

quotes: ["error", "double"];

With VS Code

You should read this entire thing. Serious!

Once you have done one, or both, of the above installs. You probably want your editor to lint and fix for you. Here are the instructions for VS Code:

1. Install the ESLint package
2. Now we need to setup some VS Code settings via Code/File → Preferences → Settings. It's easier to enter these settings while editing the settings.json file, so click the Open (Open Settings) icon in the top right corner:

// These are all my auto-save configs
"editor.formatOnSave": true,
// turn it off for JS and JSX, we will do this via eslint
"[javascript][javascriptreact][typescript][typescriptreact]": {
  "editor.formatOnSave": false
},
// tell the ESLint plugin to run on save
"editor.codeActionsOnSave": {
  "source.fixAll.eslint": true
},

After attempting to lint your file for the first time, you may need to click on 'ESLint' in the bottom right and select 'Allow Everywhere' in the alert window.

Finally you'll usually need to restart VS code. They say you don't need to, but it's never worked for me until I restart.

With Create React App

1. Run npx install-peerdeps --dev @iammattburns/eslint-config
2. Crack open your package.json and replace "extends": "react-app" with "extends": "@iammattburns/eslint-config"

With Gatsby

1. Run npx install-peerdeps --dev @iammattburns/eslint-config
2. follow the Local / Per Project Install steps above

With WSL

It should work as above.

With JetBrains Products (IntelliJ IDEA, WebStorm, RubyMine, PyCharm, PhpStorm, etc)

If you have previously configured ESLint to run via a File Watcher, turn that off.

If you choose Local / Per Project Install Above

1. Open ESLint configuration by going to File > Settings (Edit > Preferences on Mac) > Languages & Frameworks > Code Quality Tools > ESLint (optionally just search settings for "eslint")
2. Select Automatic ESLint Configuration
3. Check Run eslint --fix on save

If you choose Global Install

The following steps are for a typical Node / ESLint global installtion. If you have a customized setup, refer to JetBrains docs for more ESLint Configuration Options.

1. Open ESLint configuration by going to File > Settings (Edit > Preferences on Mac) > Languages & Frameworks > Code Quality Tools > ESLint (optionally just search settings for "eslint")
2. Select Manual ESLint configuration
3. Choose your Node interpreter from the detected installations
4. Select the global ESLint package from the dropdown
5. Leave Configuration File as Automatic Search
6. Check Run eslint --fix on save

Ensure the Prettier plugin is disabled if installed.

1. Open Prettier configuration by going to File > Settings (Edit > Preferences on Mac) > Languages & Frameworks > Code Quality Tools > Prettier (optionally just search settings for "prettier")
2. Uncheck both On code reformat and On save
3. Optional BUT IMPORTANT: If you have the Prettier extension enabled for other languages like CSS and HTML, turn it off for JS since we are doing it through Eslint already.
   1. Make sure the Run for files glob does not include js,ts,jsx,tsx.
   2. An example glob for styles, config, and markdown. {**/*,*}.{yml,css,sass,md}

With Typescript

Same instructions as above, just make sure you extend @iammattburns/eslint-config/typescript instead of just @iammattburns/eslint-config.

With Yarn

It should just work! Open an issue if not.

With pnpm

It should just work! Open an issue if not.

Issues with ESLint not formatting code

If you experience issues with ESLint not formatting the code or you receive a Parsing error: Cannot find module '@babel/preset-react error message then you need to check that you opened the folder where you installed and configured ESLint directly in VS Code. The correct folder to open will be the one where you installed the @iammattburns/eslint-config npm package and where you created the .eslintrc file.

Opening a parent folder or child folder in your code editor will cause ESLint to fail in finding the ESLint npm packages and the formatting won't work.

your-username
  |
  projects
    |
    beginner-javascript # <- Open this folder directly in your code editor
      .eslintrc
      package.json
      node_modules/
      exercises/
      playground/