index.js

/* eslint-disable @typescript-eslint/naming-convention */
module.exports = {
  extends: [
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/stylistic',
    'plugin:@typescript-eslint/strict',
    'eslint-config-prettier',
  ],
  parser: '@typescript-eslint/parser',
  plugins: ['@typescript-eslint', 'prettier'],
  settings: {
    'import/parsers': {
      '@typescript-eslint/parser': ['.ts', '.tsx', '.d.ts'],
    },
    'import/resolver': {
      node: {
        extensions: ['.mjs', '.js', '.json', '.ts', '.d.ts'],
      },
    },
    'import/extensions': ['.js', '.mjs', '.jsx', '.ts', '.tsx', '.d.ts'],
    'import/external-module-folders': ['node_modules', 'node_modules/@types'],
  },
  rules: {
    // @typescript-eslint overrides that work better than ESLint.
    // The base rule needs to be disabled to prevent false positives.

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/naming-convention.md
    camelcase: 'off',
    '@typescript-eslint/naming-convention': [
      'error',
      {
        selector: 'default',
        format: ['camelCase', 'UPPER_CASE', 'PascalCase', 'snake_case'],
      },
      {
        selector: 'variable',
        format: ['camelCase', 'UPPER_CASE', 'PascalCase', 'snake_case'],
      },
      {
        selector: 'parameter',
        format: ['camelCase', 'UPPER_CASE', 'PascalCase', 'snake_case'],
        leadingUnderscore: 'allow',
      },
      {
        // Matches: class, interface, typeAlias, enum, typeParameter
        selector: 'typeLike',
        format: ['PascalCase'],
      },
      {
        selector: 'enumMember',
        format: ['PascalCase'],
      },
    ],

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-dupe-class-members.md
    'no-dupe-class-members': 'off',
    '@typescript-eslint/no-dupe-class-members': ['error'],

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-loop-func.md
    'no-loop-func': 'off',
    '@typescript-eslint/no-loop-func': 'error',

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-redeclare.md
    'no-redeclare': 'off',
    '@typescript-eslint/no-redeclare': ['error'],

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-shadow.md
    'no-shadow': 'off',
    '@typescript-eslint/no-shadow': ['error'],

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-unused-expressions.md
    'no-unused-expressions': 'off',
    '@typescript-eslint/no-unused-expressions': ['error'],

    // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-use-before-define.md
    'no-use-before-define': 'off',
    '@typescript-eslint/no-use-before-define': ['error'],

    // Override Airbnb 'import/extensions' rule. Add 'ts' and 'tsx'.
    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/extensions.md
    'import/extensions': [
      'error',
      'ignorePackages',
      {
        js: 'never',
        mjs: 'never',
        jsx: 'never',
        ts: 'never',
        tsx: 'never',
      },
    ],

    // Override Airbnb 'import/no-extraneous-dependencies' rule. Add 'ts' and 'tsx'.
    // https://github.com/benmosher/eslint-plugin-import/blob/master/docs/rules/no-extraneous-dependencies.md
    'import/no-extraneous-dependencies': [
      'error',
      {
        devDependencies: [
          'test/**',
          'tests/**',
          'spec/**',
          '**/__tests__/**',
          '**/__mocks__/**',
          'test.{js,jsx,ts,tsx}',
          'test-*.{js,jsx,ts,tsx}',
          '**/*{.,_}{test,spec}.{js,jsx,ts,tsx}',
          '**/jest.config.js',
          '**/jest.setup.js',
          '**/vue.config.js',
          '**/webpack.config.js',
          '**/webpack.config.*.js',
          '**/rollup.config.js',
          '**/rollup.config.*.js',
          '**/gulpfile.js',
          '**/gulpfile.*.js',
          '**/Gruntfile{,.js}',
          '**/protractor.conf.js',
          '**/protractor.conf.*.js',
          '**/karma.conf.js',
        ],
        optionalDependencies: false,
      },
    ],

    // See https://github.com/typescript-eslint/typescript-eslint/issues/7227
    '@typescript-eslint/no-invalid-void-type': 'off',
  },
  overrides: [
    {
      // Enable the rule specifically for TypeScript files
      files: ['*.ts', '*.tsx'],
      rules: {
        // Required for mixed JS/TS code bases - https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/explicit-function-return-type.md
        '@typescript-eslint/explicit-function-return-type': ['error'],

        // Disable the following rules since the TypeScript
        // compiler does it.
        'constructor-super': 'off',
        'getter-return': 'off',
        'no-const-assign': 'off',
        'no-dupe-args': 'off',
        'no-dupe-keys': 'off',
        'no-func-assign': 'off',
        'no-new-symbol': 'off',
        'no-obj-calls': 'off',
        'no-this-before-super': 'off',
        'no-undef': 'off',
        'no-unreachable': 'off',
        'no-unsafe-negation': 'off',
        'valid-typeof': 'off',
        'import/named': 'off',
        'import/no-unresolved': 'off',
      },
    },
    {
      files: ['**/*.spec.js', '**/*.test.js', '**/tests-*.js', '**/*.spec.ts', '**/*.test.ts', '**/tests-*.ts'],
      rules: {
        '@typescript-eslint/no-non-null-assertion': 'off',
      },
    },
  ],
};