.eslintrc.js

module.exports = {
  env: {
    es6: true,
    node: true,
  },
  extends: [
    'plugin:@typescript-eslint/recommended',
    'plugin:@typescript-eslint/recommended-requiring-type-checking',
    'plugin:import/recommended',
    'plugin:prettier/recommended',
    'plugin:jest/recommended',
  ],
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: 'tsconfig.json',
    sourceType: 'module',
  },
  plugins: ['@typescript-eslint', 'import', 'jest', 'no-null', 'prefer-arrow'],
  root: true,
  rules: {
    '@typescript-eslint/adjacent-overload-signatures': 'error',
    '@typescript-eslint/array-type': [
      'error',
      {
        default: 'array',
      },
    ],
    '@typescript-eslint/ban-types': [
      'error',
      {
        types: {
          Object: {
            message: 'Avoid using the `Object` type. Did you mean `object`?',
          },
          Function: {
            message: 'Avoid using the `Function` type. Prefer a specific function type, like `() => void`.',
          },
          Boolean: {
            message: 'Avoid using the `Boolean` type. Did you mean `boolean`?',
          },
          Number: {
            message: 'Avoid using the `Number` type. Did you mean `number`?',
          },
          String: {
            message: 'Avoid using the `String` type. Did you mean `string`?',
          },
          Symbol: {
            message: 'Avoid using the `Symbol` type. Did you mean `symbol`?',
          },
        },
      },
    ],
    '@typescript-eslint/consistent-type-assertions': 'error',
    '@typescript-eslint/explicit-function-return-type': 'off',
    '@typescript-eslint/explicit-member-accessibility': [
      'error',
      {
        accessibility: 'explicit',
        overrides: {
          constructors: 'no-public',
        },
      },
    ],
    '@typescript-eslint/explicit-module-boundary-types': 'off',
    '@typescript-eslint/indent': 'off', // enforced by prettier
    '@typescript-eslint/member-delimiter-style': [
      'off',
      {
        multiline: {
          delimiter: 'none',
          requireLast: true,
        },
        singleline: {
          delimiter: 'semi',
          requireLast: false,
        },
      },
    ],
    '@typescript-eslint/member-ordering': 'error',
    '@typescript-eslint/naming-convention': [
      'error',
      {
        selector: 'variable',
        format: ['camelCase', 'PascalCase', 'UPPER_CASE'],
        leadingUnderscore: 'allow',
        trailingUnderscore: 'forbid',
      },
    ],
    '@typescript-eslint/no-empty-function': 'off', // allows empty functions, e.g. () => {}
    '@typescript-eslint/no-empty-interface': 'error',
    '@typescript-eslint/no-explicit-any': 'off',
    '@typescript-eslint/no-inferrable-types': 'error',
    '@typescript-eslint/no-misused-new': 'error',
    '@typescript-eslint/no-namespace': 'error',
    '@typescript-eslint/no-parameter-properties': 'off',
    '@typescript-eslint/no-extra-semi': 'off', // enforced by prettier
    '@typescript-eslint/prefer-regexp-exec': 'off',
    '@typescript-eslint/unbound-method': 'warn',
    '@typescript-eslint/no-unsafe-assignment': 'warn',
    '@typescript-eslint/no-unsafe-return': 'warn',
    '@typescript-eslint/no-unsafe-member-access': 'warn',
    '@typescript-eslint/no-unsafe-call': 'warn',
    '@typescript-eslint/no-unsafe-argument': 'warn',
    '@typescript-eslint/require-await': 'off',
    '@typescript-eslint/restrict-template-expressions': 'warn',
    '@typescript-eslint/no-shadow': [
      'error',
      {
        hoist: 'all',
      },
    ],
    '@typescript-eslint/no-unnecessary-boolean-literal-compare': 'error',
    '@typescript-eslint/no-unnecessary-qualifier': 'error',
    '@typescript-eslint/no-unused-expressions': 'error',
    '@typescript-eslint/no-unused-vars': [
      'error',
      {
        args: 'none', // allows unused variables in function arguments
        ignoreRestSiblings: true, // allows unused variables in object destructuring
        varsIgnorePattern: '_', // allows unused _ variables (for array destructuring)
      },
    ],
    '@typescript-eslint/no-use-before-define': 'off',
    '@typescript-eslint/no-var-requires': 'warn',
    '@typescript-eslint/prefer-for-of': 'error',
    '@typescript-eslint/prefer-function-type': 'error',
    '@typescript-eslint/prefer-namespace-keyword': 'error',
    '@typescript-eslint/quotes': [
      'error',
      'single',
      {
        avoidEscape: true,
        allowTemplateLiterals: true,
      },
    ],
    '@typescript-eslint/semi': ['off', null],
    '@typescript-eslint/triple-slash-reference': [
      'error',
      {
        path: 'always',
        types: 'prefer-import',
        lib: 'always',
      },
    ],
    '@typescript-eslint/type-annotation-spacing': 'off',
    '@typescript-eslint/typedef': 'off',
    '@typescript-eslint/unified-signatures': 'error',
    'arrow-parens': ['off', 'always'],
    'brace-style': ['error', '1tbs'],
    'comma-dangle': [
      'error',
      {
        arrays: 'always-multiline',
        functions: 'never',
        imports: 'always-multiline',
        objects: 'always-multiline',
      },
    ],
    complexity: 'off',
    'constructor-super': 'error',
    curly: 'error',
    'dot-notation': 'off',
    'eol-last': 'error',
    eqeqeq: ['error', 'smart'],
    'guard-for-in': 'error',
    'id-denylist': 'error',
    'id-match': 'error',
    'import/no-extraneous-dependencies': 'error',
    'import/order': [
      'error',
      {
        alphabetize: {order: 'asc', caseInsensitive: true},
        'newlines-between': 'always',
        groups: [['builtin', 'object'], 'type', 'external', 'internal', 'parent', ['sibling', 'index']],
        // set different groups for 5 different import levels ('../../../../**', '../../../**', ...)
        pathGroups: [
          ...Array.from({length: 5}).map((_, index) => ({
            pattern: `${'../'.repeat(5 + 1 - index)}**`,
            group: 'parent',
            position: 'before',
          })),
        ],
      },
    ],
    indent: 'off', // enforced by prettier
    'linebreak-style': ['error', 'unix'],
    'max-classes-per-file': ['error', 3],
    'max-len': 'off',
    'new-parens': 'off',
    'newline-per-chained-call': 'off',
    'no-bitwise': 'error',
    'no-caller': 'error',
    'no-cond-assign': 'error',
    'no-console': 'off',
    'no-debugger': 'error',
    'no-empty': 'error',
    'no-empty-function': 'off',
    'no-eval': 'error',
    'no-extra-semi': 'off',
    'no-fallthrough': 'off',
    'no-invalid-this': 'off',
    'no-irregular-whitespace': 'error',
    'no-multiple-empty-lines': 'error',
    'no-new-wrappers': 'error',
    'no-return-await': 'error',
    'no-shadow': 'off',
    'no-throw-literal': 'error',
    'no-trailing-spaces': 'error',
    'no-undef-init': 'error',
    'no-underscore-dangle': 'off',
    'no-unsafe-finally': 'error',
    'no-unsafe-member-access': 'off',
    'no-unused-expressions': 'off',
    'no-unused-labels': 'error',
    'no-unused-vars': 'off',
    'no-use-before-define': 'off',
    'no-var': 'error',
    'no-null/no-null': 'error',
    'object-shorthand': 'error',
    'one-var': ['error', 'never'],
    'padded-blocks': [
      'off',
      {
        blocks: 'never',
      },
      {
        allowSingleLineBlocks: true,
      },
    ],
    'padding-line-between-statements': [
      'error',
      {
        blankLine: 'always',
        prev: '*',
        next: 'return',
      },
    ],
    'prefer-arrow/prefer-arrow-functions': 'error',
    'prefer-const': 'error',
    'prefer-object-spread': 'error',
    'quote-props': ['error', 'as-needed'],
    quotes: 'off',
    radix: 'error',
    semi: 'off',
    'space-before-function-paren': 'off',
    'space-in-parens': ['off', 'never'],
    'spaced-comment': [
      'error',
      'always',
      {
        markers: ['/'],
      },
    ],
    'use-isnan': 'error',
    'valid-typeof': 'off',
    'jest/no-interpolation-in-snapshots': 'off', // allow showing from which variable comes a specific value in inline snapshots
    'no-restricted-imports': [
      'error',
      {
        paths: [
          {
            // forbid using named imports for chalk
            // since we can't restrict to only using default imports, this is a list of all chalk members
            name: 'chalk',
            importNames: [
              'Instance',
              'level',
              'hex',
              'keyword',
              'rgb',
              'hsl',
              'hsv',
              'hwb',
              'ansi',
              'ansi256',
              'bgHex',
              'bgKeyword',
              'bgRgb',
              'bgHsl',
              'bgHsv',
              'bgHwb',
              'bgAnsi',
              'bgAnsi256',
              'reset',
              'bold',
              'dim',
              'italic',
              'underline',
              'inverse',
              'hidden',
              'strikethrough',
              'visible',
              'black',
              'red',
              'green',
              'yellow',
              'blue',
              'magenta',
              'cyan',
              'white',
              'gray',
              'grey',
              'blackBright',
              'redBright',
              'greenBright',
              'yellowBright',
              'blueBright',
              'magentaBright',
              'cyanBright',
              'whiteBright',
              'bgBlack',
              'bgRed',
              'bgGreen',
              'bgYellow',
              'bgBlue',
              'bgMagenta',
              'bgCyan',
              'bgWhite',
              'bgGray',
              'bgGrey',
              'bgBlackBright',
              'bgRedBright',
              'bgGreenBright',
              'bgYellowBright',
              'bgBlueBright',
              'bgMagentaBright',
              'bgCyanBright',
              'bgWhiteBright',
            ],
            message: "Please use a default import instead, e.g. `import chalk from 'chalk'`",
          },
        ],
      },
    ],
  },
  settings: {
    'import/resolver': 'typescript',
  },
}