ESLint config generator

How to use it

1. Choose JavaScript or TypeScript and where the code runs.
2. Say whether .js files use import or require.
3. Tick the rules you want and, if you format with Prettier, the Prettier option.
4. Run the npm install --save-dev … command from the first line, save the file in the project root and run npx eslint ..

How it works

The output is an array exported with export default:

• an object with only ignores — global ignores for build folders;
• js.configs.recommended from @eslint/js (and ...tseslint.configs.recommended for TypeScript);
• your block: the file patterns, ecmaVersion: 'latest', the globals and the chosen rules;
• for CommonJS, a block that sets sourceType: 'commonjs' for .js files (ESLint already treats .cjs as CommonJS);
• eslintConfigPrettier last, if chosen.

Example

The defaults (JavaScript, browser, ES modules, recommended rules, eqeqeq, prefer-const, unused variables as warnings) give:

// npm install --save-dev eslint @eslint/js globals
import js from '@eslint/js';
import globals from 'globals';

export default [
  { ignores: ['dist/', 'build/', 'coverage/'] },
  js.configs.recommended,
  {
    files: ['**/*.{js,mjs,cjs}'],
    languageOptions: {
      ecmaVersion: 'latest',
      globals: globals.browser,
    },
    rules: {
      eqeqeq: ['error', 'always'],
      'prefer-const': 'error',
      'no-unused-vars': 'warn',
    },
  },
];

Tips

• Add "lint": "eslint ." to the scripts in package.json so everyone runs the same command.
• npx eslint . --fix repairs what can be fixed automatically, such as let that should be const.
• Let Prettier handle formatting and ESLint handle code quality; that is what the Prettier option is for.