.eslintrc.js

// @ts-check
/** @type {import('@typescript-eslint/utils').TSESLint.Linter.Config} */
const config = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    ecmaVersion: 2020,
    project: ['tsconfig.json'],
  },
  plugins: ['@typescript-eslint', 'etc'],
  reportUnusedDisableDirectives: true,
  extends: [
    'eslint:recommended',
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/recommended-requiring-type-checking',
    'prettier',
  ],
  rules: {
    '@typescript-eslint/consistent-generic-constructors': 'error',
    '@typescript-eslint/consistent-type-assertions': 'error',
    '@typescript-eslint/consistent-type-imports': 'error',
    '@typescript-eslint/consistent-type-exports': 'error',
    '@typescript-eslint/explicit-module-boundary-types': 'error',
    '@typescript-eslint/naming-convention': [
      'error',
      {
        selector: 'variableLike',
        format: ['PascalCase', 'camelCase'],
        leadingUnderscore: 'allow',
      },
    ],
    '@typescript-eslint/no-non-null-assertion': 'error',
    '@typescript-eslint/no-shadow': ['error', { ignoreTypeValueShadow: true }],
    '@typescript-eslint/no-unused-vars': [
      'error',
      {
        args: 'after-used',
        // Follow the typescript pattern of ignoring things starting with _
        argsIgnorePattern: '^_',
        destructuredArrayIgnorePattern: '^_',
        varsIgnorePattern: '^_',
        ignoreRestSiblings: true,
      },
    ],
    '@typescript-eslint/prefer-for-of': 'error',
    'etc/no-deprecated': 'error',
    // ESLint has a built-in version of this rule without the allowTypeImports functionality.
    // Some overrides use the built-in ESLint rule to set additional restricted imports without
    // overriding these defaults.
    '@typescript-eslint/no-restricted-imports': [
      'error',
      {
        paths: [
          {
            name: 'node:test',
            message: 'You probably meant to import from "@jest/globals"',
          },
        ],
      },
    ],
    'no-restricted-properties': [
      'error',
      {
        object: 'fs',
        property: 'promises',
        message: 'Import "fs/promises" directly instead. This allows methods to be mocked with Jest.',
      },
      {
        object: 'process',
        property: 'cwd',
        message: 'Pass the proper cwd through to avoid accidentally running operations in the wrong context.',
      },
      {
        object: 'process',
        property: 'chdir',
        message:
          'beachball should not be dependent on the actual process.cwd(). Ensure the proper cwd is passed through instead.',
      },
      {
        object: 'process',
        property: 'exit',
        message: 'Errors should be propagated to the top level and handled there.',
      },
    ],

    // Downgrade these rules to warnings because they cause excessive/unhelpful noise when
    // the actual problem is type errors due to a missing import...
    // With the rules as warnings, there will only be "red squiggles" at the spot of the type error
    // rather than sometimes covering the whole statement.
    '@typescript-eslint/no-unsafe-argument': 'warn',
    '@typescript-eslint/no-unsafe-assignment': 'warn',
    '@typescript-eslint/no-unsafe-call': 'warn',
    '@typescript-eslint/no-unsafe-member-access': 'warn',
    '@typescript-eslint/no-unsafe-return': 'warn',

    // Disabled rules from extended configs:
    'no-undef': 'off',
    'no-regex-spaces': 'off',
    // This rule requires using Record instead of index signatures, and it's disabled because
    // sometimes the key name can be useful for documentation.
    '@typescript-eslint/consistent-indexed-object-style': 'off',
    // Don't restrict types of `template expression ${operands}`.
    '@typescript-eslint/restrict-template-expressions': 'off',
    // Right now this rule gives unnecessary warnings about comparisons with string literals,
    // which the compiler would flag anyway. It could be helpful if there was a future fix or
    // option to ignore those types of safe comparisons.
    '@typescript-eslint/no-unsafe-enum-comparison': 'off',
  },
  overrides: [
    {
      files: ['*.js', '*.mjs'],
      parserOptions: {
        sourceType: 'module',
      },
      rules: {
        // Rule doesn't handle JS files
        '@typescript-eslint/explicit-module-boundary-types': 'off',
      },
    },
    {
      files: ['**/__e2e__/**', '**/__fixtures__/**', '**/__functional__/**', '**/__tests__/**'],
      rules: {
        '@typescript-eslint/no-non-null-assertion': 'off',
        '@typescript-eslint/no-empty-function': 'off',
        'no-restricted-properties': [
          'error',
          ...['describe', 'it', 'test']
            .map(func => [
              { object: func, property: 'only', message: 'Do not commit .only() tests' },
              { object: func, property: 'skip', message: 'Do not commit .skip() tests (disable this rule if needed)' },
            ])
            .flat(),
        ],
        // Use the ESLint version of the rule to avoid overriding the restricted imports from the base config
        'no-restricted-imports': [
          'error',
          {
            paths: [
              {
                name: '@jest/globals',
                importNames: ['xdescribe', 'xit', 'xtest'],
                message: 'Do not commit disabled tests (disable this rule if needed)',
              },
            ],
          },
        ],
      },
    },
  ],
};

module.exports = config;