Eslint and Prettier Setup

These are Yellow Card settings for ESLint and Prettier

You might like them - or you might not. Suggest a change and we can discuss as a team.

What it does

• Lints JavaScript based on the latest standards
• Fixes issues and formatting errors with Prettier
• You can see all the rules here

Installing

Project Install

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

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

This is a little dumb, but essentially we have to install Eslint and Prettier as Peer Dependencies of the project so it can execute the formatting. Copy and paste or run the bash script in the folder.

(
  export PKG=@yellowcard/eslint-config-yellowcard;
  npm info "$PKG@latest" peerDependencies --json | command sed 's/[\{\},]//g ; s/: /@/g' | xargs npm install --save-dev "$PKG@latest"
)

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

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

{
  "extends": [
    "@yellowcard/yellowcard"
  ]
}

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

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.

7. To use from the CLI, you can now run eslint . or configure your editor as we show next.

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" while prettier options go under "prettier/prettier". Note that prettier rules overwrite anything in my config (trailing comma, and single quote), so you'll need to include those as well.

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

With VS Code - This part is very finicky

Once you have done one, or both, of the above installs. You may optionally 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 {} 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]": {
  "editor.formatOnSave": false
},
"[javascriptreact]": {
  "editor.formatOnSave": false
},
// tell the ESLint plugin to run on save
"eslint.autoFixOnSave": true,
// 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
"prettier.disableLanguages": ["javascript", "javascriptreact"],