.eslintrc.js

module.exports = {
  root: true,
  env: {
    es6: true,
    node: true,
    browser: true,
    jest: true,
  },
  extends: [
    'airbnb',
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/eslint-recommended',
    'prettier',
    'plugin:prettier/recommended',
  ],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint', 'prettier'],
  rules: {
    'dot-notation': 'off',
    'jsx-a11y/anchor-is-valid': 'off',
    'jsx-a11y/label-has-associated-control': 'off',
    'react/jsx-closing-tag-location': 'off',
    'react/jsx-curly-brace-presence': 'off',
    'react/jsx-filename-extension': ['error', { extensions: ['.jsx', '.tsx'] }],
    'react/jsx-one-expression-per-line': 'off',
    'react/jsx-props-no-spreading': 'off',
    'react/jsx-wrap-multilines': 'off',

    // Cannot use `Component.displayName` pattern on class components in TS.
    'react/static-property-placement': 'off',

    // Require or disallow a space immediately following the // or /* in a comment
    // https://eslint.org/docs/rules/spaced-comment
    'spaced-comment': [
      'error',
      'always',
      {
        line: {
          exceptions: ['-', '+'],
          markers: ['=', '!', '#region', '#endregion', '/'], // space here to support sprockets directives and typescript reference comments
        },
        block: {
          exceptions: ['-', '+'],
          markers: ['=', '!', '#region', '#endregion', ':', '::'], // space here to support sprockets directives and flow comment types
          balanced: true,
        },
      },
    ],
  },
  settings: {
    'import/resolver': {
      node: {
        extensions: ['.js', '.mjs', '.jsx', '.ts', '.tsx', '.json'],
      },
      typescript: {},
    },
    'import/extensions': ['.js', '.mjs', '.jsx', '.ts', '.tsx'],
  },
  overrides: [
    {
      files: ['**/*.ts', '**/*.tsx'],
      parserOptions: {
        // typescript-eslint specific options
        warnOnUnsupportedTypeScriptVersion: true,
      },
      rules: {
        // Allow unused variables that starts with, or is `_`
        'no-unused-vars': 'off',
        '@typescript-eslint/no-unused-vars': [
          'warn',
          {
            vars: 'all',
            args: 'after-used',
            ignoreRestSiblings: true,
            argsIgnorePattern: '^_',
            varsIgnorePattern: '^_',
          },
        ],

        // Override the base rules so to not clash with each other.
        // https://github.com/typescript-eslint/typescript-eslint/issues/2540
        'no-use-before-define': 'off',
        '@typescript-eslint/no-use-before-define': ['error', { functions: true, classes: true, variables: true }],

        // Allow `.ts` and `.tsx` extensions to be omitted
        'import/extensions': [
          'error',
          'ignorePackages',
          {
            js: 'never',
            mjs: 'never',
            jsx: 'never',
            ts: 'never',
            tsx: 'never',
          },
        ],

        // Extend this config for TypeScript files
        'import/no-extraneous-dependencies': [
          'error',
          {
            devDependencies: [
              'test/**', // tape, common npm pattern
              'tests/**', // also common npm pattern
              'spec/**', // mocha, rspec-like pattern
              '**/jest.config.ts', // jest config
              '**/jest.setup.ts', // jest setup
              '**/__tests__/**', // jest pattern
              '**/__mocks__/**', // jest pattern
              '**/__stories__/**', // storybook files
              'test.{ts,tsx}', // repos with a single test file
              'test-*.{ts,tsx}', // repos with multiple top-level test files
              '**/*{.,_}{test,spec}.{ts,tsx}', // tests where the extension or filename suffix denotes that it is a test
              '**/*{.,_}{stories,story}.{ts,tsx}', // storybook files
            ],
            optionalDependencies: false,
          },
        ],

        // No need to use prop types on TS files.
        'react/prop-types': 'off',

        '@typescript-eslint/camelcase': 'off',
        '@typescript-eslint/explicit-module-boundary-types': ['off'],
      },
    },
    {
      files: ['.eslintrc.js', '*.config.js'],
      parserOptions: { sourceType: 'script' },
      env: { node: true },
    },
  ],
};