index.js

module.exports = {
  parser: '@typescript-eslint/parser',
  plugins: [
    '@typescript-eslint',
    '@stylistic/ts',
    'deprecation',
  ],
  settings: {
    'import/parsers': {
      '@typescript-eslint/parser': ['.ts', '.tsx'],
    },
    'import/resolver': {
      node: {
        extensions: ['.js', '.jsx', '.ts', '.tsx'],
      },
    },
  },
  extends: [
    'plugin:@typescript-eslint/recommended',
    'plugin:deprecation/recommended',
  ],
  rules: {
    'brace-style': 'off',
    camelcase: 'off',
    'func-call-spacing': 'off',
    'no-shadow': 'off',
    'no-use-before-define': 'off',
    indent: 'off',
    'import/extensions': [
      'error',
      'ignorePackages',
      {
        js: 'never',
        jsx: 'never',
        ts: 'never',
        tsx: 'never',
      },
    ],
    '@typescript-eslint/array-type': 'error',
    '@stylistic/ts/brace-style': ['error', '1tbs', { allowSingleLine: true }],
    '@typescript-eslint/consistent-type-imports': [
      'error',
      {
        prefer: 'type-imports',
        disallowTypeAnnotations: true,
      },
    ],
    '@typescript-eslint/explicit-member-accessibility': 'error',
    '@stylistic/ts/func-call-spacing': ['error'],
    '@stylistic/ts/indent': [
      'error',
      2,
      {
        ignoredNodes: [
          'FunctionExpression > .params[decorators.length > 0]',
          'FunctionExpression > .params > :matches(Decorator, :not(:first-child))',
          'ClassBody.body > PropertyDefinition[decorators.length > 0] > .key',
        ],
      },
    ],
    '@stylistic/ts/member-delimiter-style': ['error', {
      multiline: {
        delimiter: 'none',
        requireLast: false,
      },
      singleline: {
        delimiter: 'comma',
        requireLast: false,
      },
      multilineDetection: 'brackets',
    }],
    '@typescript-eslint/naming-convention': [
      'error',
      {
        selector: 'default',
        format: ['camelCase'],
      },

      {
        selector: 'variable',
        format: ['camelCase', 'UPPER_CASE'],
      },
      {
        selector: 'parameter',
        format: ['camelCase'],
        leadingUnderscore: 'allow',
      },

      {
        selector: 'memberLike',
        modifiers: ['private'],
        format: ['camelCase'],
        leadingUnderscore: 'allow',
      },
      {
        selector: 'typeLike',
        format: ['PascalCase'],
      },
    ],
    '@typescript-eslint/no-empty-function': 'off',
    '@typescript-eslint/no-shadow': ['error'],
    '@typescript-eslint/no-use-before-define': ['error', { functions: false }],
    '@typescript-eslint/prefer-includes': 'error',
    '@typescript-eslint/prefer-nullish-coalescing': 'error',
    '@typescript-eslint/prefer-optional-chain': 'error',
    '@typescript-eslint/prefer-string-starts-ends-with': 'error',
    '@typescript-eslint/prefer-reduce-type-parameter': 'error',
    '@stylistic/ts/type-annotation-spacing': 'error',
  },
  overrides: [
    {
      files: [
        '**/*.js',
        '**/*.jsx',
      ],
      rules: {
        '@typescript-eslint/explicit-function-return-type': 'off',
        '@typescript-eslint/explicit-module-boundary-types': 'off',
        '@stylistic/ts/indent': 'off',
      },
    },
    {
      files: [
        '**/*.jsx',
        '**/*.tsx',
      ],
      rules: {
        '@typescript-eslint/naming-convention': [
          'error',
          {
            selector: 'default',
            format: ['camelCase'],
          },

          {
            selector: 'variable',
            format: ['camelCase', 'UPPER_CASE', 'PascalCase'],
          },
          {
            selector: 'parameter',
            format: ['camelCase'],
            leadingUnderscore: 'allow',
          },

          {
            selector: 'memberLike',
            modifiers: ['private'],
            format: ['camelCase'],
            leadingUnderscore: 'allow',
          },
          {
            selector: 'typeLike',
            format: ['PascalCase'],
          },
        ],
      },
    },
  ],
}