.eslintrc.js

module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint'],
  extends: [
    'plugin:@typescript-eslint/recommended',
    'airbnb',
    'airbnb/hooks',
    'prettier',
    'prettier/@typescript-eslint',
    'prettier/react',
  ],
  parserOptions: {
    ecmaVersion: 9,
    sourceType: 'module',
    ecmaFeatures: {
      jsx: true,
    },
  },
  settings: {
    'import/resolver': {
      parcel: {
        rootDir: 'src',
        extensions: ['.js', '.jsx', '.ts', '.tsx'],
      },
      node: {
        paths: ['src'],
        extensions: ['.js', '.jsx', '.ts', '.tsx'],
      },
    },
  },
  env: {
    browser: true,
    es6: true,
    node: true,
    jest: true,
  },
  rules: {
    quotes: ['off'], // https://github.com/prettier/eslint-config-prettier#quotes
    'no-unexpected-multiline': 'off', // https://github.com/prettier/eslint-config-prettier#no-unexpected-multiline,
    'arrow-parens': ['off'], // handled by prettier with rule 'arrowParens'
    'react/jsx-filename-extension': [1, { extensions: ['.jsx', '.tsx'] }], // https://github.com/yannickcr/eslint-plugin-react/blob/master/docs/rules/jsx-filename-extension.md
    // https://github.com/benmosher/eslint-plugin-import/issues/1568
    'import/extensions': [
      'error',
      'ignorePackages',
      {
        js: 'never',
        jsx: 'never',
        ts: 'never',
        tsx: 'never',
      },
    ],
  },
  overrides: [
    {
      files: ['*.js'],
      rules: {
        '@typescript-eslint/no-var-requires': 'warn', // https://github.com/airbnb/javascript#modules--use-them
      },
    },
    {
      files: ['*.js', '*.jsx'],
      rules: {
        '@typescript-eslint/no-unused-vars': 'off', // duplicate of by no-unused-vars
        '@typescript-eslint/explicit-function-return-type': 'off', // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/explicit-function-return-type.md#configuring-in-a-mixed-jsts-codebase
      },
    },
    {
      files: ['*.ts', '*.tsx'],
      rules: {
        'no-unused-vars': 'off', // duplicate of @typescript-eslint/no-unused-vars
        '@typescript-eslint/explicit-function-return-type': ['error'], // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/explicit-function-return-type.md#configuring-in-a-mixed-jsts-codebase
      },
    },
  ],
};