Setting up Prettier and ESLint with pre-commit hook

prettier-eslint-precommit.md

Setting up Prettier and ESLint with pre-commit hook

• Initialize Git repository

  git init

• Create .gitignore file and add the following:

  node_modules/
  *.env
  

• Create a package.json file with npm init

  npm init -y

• Install dev dependencies

  npm i -D prettier eslint husky lint-staged

• Initialize ESLint config

  npx eslint --init

• Create .prettierrc file and add the following rules:

  {
    "printWidth": 80,
    "tabWidth": 2,
    "useTabs": false,
    "semi": true,
    "singleQuote": true,
    "quoteProps": "as-needed",
    "jsxSingleQuote": false,
    "trailingComma": "all",
    "bracketSpacing": true,
    "jsxBracketSameLine": true,
    "arrowParens": "avoid",
    "endOfLine": "auto"
  }

• Open package.json file and add the following sections:

  "husky": {
    "hooks": {
      "pre-commit": "lint-staged"
    }
  },
  "lint-staged": {
    "*.{js,jsx}": [
      "prettier --write",
      "eslint --fix",
      "git add"
    ],
    "*.{html,css,less,ejs}": [
      "prettier --write",
      "git add"
    ]
  }

• At this point, your pre-commit linting setup should be working and ready for use.

Make your first commit

• Open .eslintrc.js file and add no-console rule under rules section.

  module.exports = {
    ...
    rules: {
      'no-console': 'off',
    },
  };

• Add this sample app.js file:

  console.log('one');
  var ww = process.env.NODE_ENV.trim.toLowerCase();
  if (ww === 'production') {
    console.log('Another one');
  } else {
    console.log('test');
  }

• Commit all files

  git add .
  git commit -m "Initial commit"

• If all goes well, your app.js should now be formatted properly :

  console.log('one');
  const ww = process.env.NODE_ENV.trim.toLowerCase();
  if (ww === 'production') {
    console.log('Another one');
  } else {
    console.log('test');
  }