Creo Eslint and Prettier Setup

These are opinionated settings for ESLint and Prettier.

Warning These will change from time to time. Hopefully for the best!

What it does

• Lints JavaScript, Typescript, React and NestJs based on the latest standards
• Fixes issues and formatting errors with Prettier
• Based on eslint-config-airbnb and influenced by Wesbos

Installing

You can use eslint globally and/or locally per project.

It's usually best to install this locally once per project, that way you can have project specific settings as well as sync those settings with others working on your project via git.

Local / Per Project Install

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

2. Install this package

npm i --save-dev @creolabs/eslint-config

• May require --force to be specified

3. Then we need to install everything needed by the config:

npx install-peerdeps --dev @creolabs/eslint-config

You can see in your package.json there are now a big list of devDependencies.

4. Create a .eslintrc.js file in the root of your project's directory (it should live where package.json does). Your .eslint.js file should look like the following:

{
    root: true,
    extends: [ "@creolabs" ]
}

This will use the default Javascript rules

For React projects, use @creolabs/eslint-config/react.

(React rules extend the Javascript rules)

{
    root: true,
    extends: [ "@creolabs/eslint-config/react" ]
}

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

(Typescript rules extend the Javascript rules)

{
    root: true,
    extends: [ "@creolabs/eslint-config/typescript" ]
}

For Nestjs projects, use @creolabs/eslint-config/nestjs.

(Nestjs rules extend TypeScript rules)

{
    root: true,
    extends: [ "@creolabs/eslint-config/nestjs" ]
}

You may want to use the Typescript and React rules together. In that case, it may look like this:

{
    root: true,
    extends: [ 
        "@creolabs/eslint-config/react-typescript", 
    ]
}

Note: The root value will stop eslint from using any global rules.

TypeScript users will also need a tsconfig.json file in their project. An empty object ({}) will do if this is a new project.

Tip: You can alternatively put this object in your package.json under the property "eslintConfig":. This makes one less file in your project.

5. Optionally - you may want to the following scripts to your package.json to lint and/or fix:

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

Now you can manually lint your code by running npm run lint and fix all fixable issues with npm run lint:fix. Your editor will take of this automatically however.

Settings

If you'd like to overwrite eslint or prettier settings, you can add the rules in your .eslintrc.js file. The ESLint rules go directly under "rules" while prettier options go under "prettier/prettier". Note that prettier rules overwrite anything in the eslint config (trailing comma, and single quote), so you'll need to include those as well.

{
  "extends": [
    "@creolabs/eslint-config"
  ],
  "rules": {
    "no-console": 2,
    "prettier/prettier": [
      "error",
      {
        "trailingComma": "es5",
        "singleQuote": true,
        "printWidth": 120,
        "tabWidth": 8,
      }
    ]
  }
}

With VS Code

You should read this entire thing. Seriously!

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:

"editor.formatOnSave": true,
// turn it off for JS and JSX, we will do this via eslint
"[javascript]": {
  "editor.formatOnSave": false
},
"[javascriptreact]": {
  "editor.formatOnSave": false
},
// show eslint icon at bottom toolbar
"eslint.alwaysShowStatus": true,
// tell the ESLint plugin to run on save
"editor.codeActionsOnSave": {
  "source.fixAll": 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 @creolabs/eslint-config
2. Crack open your package.json and replace "extends": "react-app" with "extends": "@creolabs"

With Gatsby

1. Run npx install-peerdeps --dev @creolabs/eslint-config
2. If you have an existing .prettierrc file, delete it.
3. follow the Local / Per Project Install steps above

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 installation. 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 creolabs/typescript instead of just creolabs.

With Yarn

It should just work, but if they aren't showing up in your package.json, try npx install-peerdeps --dev @creolabs/eslint-config -Y

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 @creolabs/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
    |
    my-project # <- Open this folder directly in your code editor
      .eslintrc
      package.json
      node_modules/
      foo/
      bah/

Development

To use this module locally while developing, you should use npm link

// Go to package directory
cd /my_packages/eslint-config
npm link

// Go to project directory
cd /my_project
npm link @creolabs/eslint-config

// Install linked package
npm install ../my_packages/eslint-config