eslint-config-niieani/src/typescript.ts

Reusable ESLint config for Beemo configured projects.

/* eslint-disable import/no-commonjs,import/no-import-module-exports */
import fs from 'fs'
import path from 'path'
import type eslint from 'eslint'
import {
  getRootProjectReferences,
  ROOT,
  TSCONFIG_JSON_PATH,
} from '@niieani/scaffold-config-constants'

let project: string[] | string = ''

// Some very large projects will run out of memory when using project references,
// so we support a custom tsconfig to work around this issue.
const tsconfigEslintPath = path.join(ROOT, 'tsconfig.eslint.json')

if (fs.existsSync(tsconfigEslintPath)) {
  project = tsconfigEslintPath
}

// Otherwise, if the consumer is using project references, we need to include a path
// to every tsconfig.json in the graph.
if (!project) {
  project =
    getRootProjectReferences()?.map((ref) =>
      path.join(ROOT, ref.path, 'tsconfig.json'),
    ) ?? TSCONFIG_JSON_PATH
}

const config: eslint.Linter.Config = {
  plugins: ['@typescript-eslint'],
  parserOptions: {
    project,
  },
  rules: {
    // Disabled by Prettier: https://github.com/prettier/eslint-config-prettier/blob/main/index.js#L95
    // We duplicate and keep track of this here so that we dont configure them
    '@typescript-eslint/brace-style': 'off',
    '@typescript-eslint/comma-dangle': 'off',
    '@typescript-eslint/comma-spacing': 'off',
    '@typescript-eslint/func-call-spacing': 'off',
    '@typescript-eslint/indent': 'off',
    '@typescript-eslint/keyword-spacing': 'off',
    '@typescript-eslint/member-delimiter-style': 'off',
    '@typescript-eslint/no-extra-parens': 'off',
    '@typescript-eslint/no-extra-semi': 'off',
    '@typescript-eslint/object-curly-spacing': 'off',
    '@typescript-eslint/semi': 'off',
    '@typescript-eslint/space-before-function-paren': 'off',
    '@typescript-eslint/space-infix-ops': 'off',
    '@typescript-eslint/type-annotation-spacing': 'off',

    // Expands upon base config to handle type annotations
    'default-param-last': 'off',
    'dot-notation': 'off',
    'lines-between-class-members': 'off',
    'no-array-constructor': 'off',
    'no-dupe-class-members': 'off',
    'no-duplicate-imports': 'off',
    'no-implied-eval': 'off',
    'no-invalid-this': 'off',
    'no-loop-func': 'off',
    'no-loss-of-precision': 'off',
    'no-redeclare': 'off',
    'no-shadow': 'off',
    'no-throw-literal': 'off',
    'no-undef': 'off', // Doesnt find namespaces
    'no-unused-expressions': 'off',
    'no-unused-vars': 'off',
    'no-use-before-define': 'off',
    'no-useless-constructor': 'off',
    quotes: 'off',
    'require-await': 'off',
    'no-return-await': 'off',
    '@typescript-eslint/default-param-last': 'error',
    '@typescript-eslint/dot-notation': 'error',
    '@typescript-eslint/lines-between-class-members': [
      'error',
      {exceptAfterOverload: true},
    ],
    '@typescript-eslint/no-array-constructor': 'error',
    '@typescript-eslint/no-dupe-class-members': 'error',
    '@typescript-eslint/no-duplicate-imports': 'off', // Prefer import plugin
    '@typescript-eslint/no-implied-eval': 'error',
    '@typescript-eslint/no-invalid-this': 'error',
    '@typescript-eslint/no-loop-func': 'error',
    '@typescript-eslint/no-loss-of-precision': 'error',
    '@typescript-eslint/no-redeclare': [
      'error',
      {ignoreDeclarationMerge: true},
    ],
    '@typescript-eslint/no-shadow': [
      'error',
      {ignoreOnInitialization: true, ignoreTypeValueShadow: true},
    ],
    '@typescript-eslint/no-throw-literal': 'error',
    '@typescript-eslint/no-unused-expressions': 'error',
    '@typescript-eslint/no-unused-vars': [
      'error',
      {
        vars: 'all',
        args: 'none',
        caughtErrors: 'all',
        ignoreRestSiblings: true,
        varsIgnorePattern: '^_',
      },
    ],
    '@typescript-eslint/no-use-before-define': [
      'error',
      {
        classes: true,
        enums: true,
        functions: true,
        typedefs: true,
        variables: true,
      },
    ],
    '@typescript-eslint/no-useless-constructor': 'error',
    '@typescript-eslint/quotes': ['error', 'single', {avoidEscape: true}],
    '@typescript-eslint/require-await': 'error',
    '@typescript-eslint/return-await': ['error', 'in-try-catch'],

    // Overloads should be stacked on top of the original signature
    '@typescript-eslint/adjacent-overload-signatures': 'error',

    // Prefer shorthand and utility types as much as possible
    '@typescript-eslint/array-type': ['error', {default: 'array'}],
    '@typescript-eslint/consistent-indexed-object-style': ['error', 'record'],
    '@typescript-eslint/method-signature-style': 'error',
    '@typescript-eslint/no-inferrable-types': [
      'error',
      {ignoreParameters: true, ignoreProperties: true}, // Vars only
    ],
    '@typescript-eslint/prefer-function-type': 'error',

    // Prefer compact and readable code
    '@typescript-eslint/no-unnecessary-boolean-literal-compare': 'error',
    '@typescript-eslint/no-redundant-type-constituents': 'error',
    '@typescript-eslint/sort-type-union-intersection-members': 'off',
    '@typescript-eslint/strict-boolean-expressions': 'off',

    // Prefer interfaces as extending and composition syntax is much nicer
    '@typescript-eslint/consistent-type-definitions': ['error', 'interface'],
    '@typescript-eslint/no-empty-interface': [
      'error',
      {allowSingleExtends: true},
    ],

    // Allow all types (except `any`) as they each serve a specific purpose
    '@typescript-eslint/ban-types': 'off',
    '@typescript-eslint/no-invalid-void-type': 'off',

    // Avoid `any` type as much as possible
    '@typescript-eslint/no-explicit-any': ['error', {ignoreRestArgs: true}],
    '@typescript-eslint/no-unsafe-argument': 'error',
    '@typescript-eslint/no-unsafe-assignment': 'error',
    '@typescript-eslint/no-unsafe-call': 'error',
    '@typescript-eslint/no-unsafe-member-access': 'error',
    '@typescript-eslint/no-unsafe-return': 'error',

    // Await is designed to auto wrap with promises for convenience, so avoid this
    '@typescript-eslint/await-thenable': 'off',

    // Require comments when using ts directives
    '@typescript-eslint/ban-ts-comment': [
      'error',
      {
        'ts-expect-error': 'allow-with-description',
        'ts-ignore': true,
        'ts-nocheck': true,
        'ts-check': false,
        minimumDescriptionLength: 3,
      },
    ],
    '@typescript-eslint/ban-tslint-comment': 'error',
    '@typescript-eslint/prefer-ts-expect-error': 'error',
    '@typescript-eslint/triple-slash-reference': [
      'error',
      {path: 'never', types: 'never', lib: 'never'},
    ],

    // Too abrasive or controversial
    '@typescript-eslint/class-literal-property-style': 'off',
    '@typescript-eslint/consistent-type-imports': 'off',
    '@typescript-eslint/naming-convention': 'off',
    '@typescript-eslint/no-dynamic-delete': 'off',
    '@typescript-eslint/no-implicit-any-catch': 'off',
    '@typescript-eslint/no-magic-numbers': 'off',
    '@typescript-eslint/no-require-imports': 'off',
    '@typescript-eslint/no-type-alias': 'off',
    '@typescript-eslint/no-unnecessary-condition': 'off', // Fails on index checks
    '@typescript-eslint/no-var-requires': 'off',
    '@typescript-eslint/prefer-enum-initializers': 'off',
    '@typescript-eslint/prefer-readonly-parameter-types': 'off',
    '@typescript-eslint/prefer-readonly': 'off',
    '@typescript-eslint/prefer-regexp-exec': 'off',
    '@typescript-eslint/require-array-sort-compare': 'off',
    '@typescript-eslint/restrict-template-expressions': 'off',
    '@typescript-eslint/typedef': 'off',
    '@typescript-eslint/unbound-method': ['off', {ignoreStatic: true}],

    // Enforce readable assertion patterns
    '@typescript-eslint/consistent-type-assertions': [
      'error',
      {
        assertionStyle: 'as',
        objectLiteralTypeAssertions: 'allow-as-parameter',
      },
    ],
    '@typescript-eslint/no-confusing-non-null-assertion': 'error',
    '@typescript-eslint/no-extra-non-null-assertion': 'error',
    '@typescript-eslint/no-non-null-asserted-nullish-coalescing': 'error',
    '@typescript-eslint/no-non-null-asserted-optional-chain': 'error',
    '@typescript-eslint/no-non-null-assertion': 'off',
    '@typescript-eslint/non-nullable-type-assertion-style': 'error',
    '@typescript-eslint/prefer-as-const': 'error',

    // Inference is powerful so allow it
    '@typescript-eslint/explicit-function-return-type': 'off',
    '@typescript-eslint/explicit-module-boundary-types': 'off',

    // Require modifiers when not public
    '@typescript-eslint/explicit-member-accessibility': [
      'error',
      {accessibility: 'no-public'},
    ],

    // Enforce explicit members for readability
    '@typescript-eslint/member-ordering': 'error',
    '@typescript-eslint/no-parameter-properties': 'error',

    // Prefer basic type casting like String()
    '@typescript-eslint/no-base-to-string': 'error',

    // Ensure promises are handled every time, even with void
    'no-void': 'off',
    '@typescript-eslint/no-confusing-void-expression': [
      'error',
      {ignoreVoidOperator: true},
    ],
    '@typescript-eslint/no-floating-promises': [
      'error',
      {
        ignoreIIFE: true,
        ignoreVoid: true,
      },
    ],
    '@typescript-eslint/no-misused-promises': [
      'error',
      {checksConditionals: true},
    ],
    '@typescript-eslint/promise-function-async': [
      'error',
      {
        allowedPromiseNames: ['Awaitable', 'PromiseLike', 'Thenable'],
        allowAny: true, // Because of unknown
        checkArrowFunctions: false,
      },
    ],

    // Encourage encapsulation and modular exports
    '@typescript-eslint/no-extraneous-class': 'error',
    '@typescript-eslint/no-namespace': [
      'error',
      {
        allowDeclarations: true,
        allowDefinitionFiles: true,
      },
    ],

    // Avoid problematic or unnecessary patterns
    '@typescript-eslint/no-duplicate-enum-values': 'error',
    '@typescript-eslint/no-for-in-array': 'error',
    '@typescript-eslint/no-misused-new': 'error',
    '@typescript-eslint/no-this-alias': ['error', {allowDestructuring: true}],
    '@typescript-eslint/no-unnecessary-qualifier': 'error',
    '@typescript-eslint/no-unnecessary-type-assertion': 'error',
    '@typescript-eslint/no-unnecessary-type-constraint': 'error',
    '@typescript-eslint/no-unused-vars-experimental': [
      'off', // Too restrictive
      {ignoreArgsIfArgsAfterAreUsed: true},
    ],
    '@typescript-eslint/prefer-for-of': 'error',
    '@typescript-eslint/prefer-literal-enum-member': 'error',
    '@typescript-eslint/prefer-reduce-type-parameter': 'error',
    '@typescript-eslint/restrict-plus-operands': [
      'error',
      {checkCompoundAssignments: true},
    ],
    '@typescript-eslint/unified-signatures': [
      'error',
      {ignoreDifferentlyNamedParameters: true},
    ],

    // Sometimes we need to be explicit because the inference is wrong
    '@typescript-eslint/no-unnecessary-type-arguments': 'off',

    // Sometimes we define empty functions in base/abstract classes
    'no-empty-function': 'off',
    '@typescript-eslint/no-empty-function': 'off',

    // Sometimes necessary because of isolated modules
    '@typescript-eslint/no-useless-empty-export': 'off',

    // Prefer modern syntax
    '@typescript-eslint/prefer-includes': 'error',
    '@typescript-eslint/prefer-namespace-keyword': 'off',
    '@typescript-eslint/prefer-nullish-coalescing': 'error',
    '@typescript-eslint/prefer-optional-chain': 'error',
    '@typescript-eslint/prefer-string-starts-ends-with': 'error',
    '@typescript-eslint/switch-exhaustiveness-check': 'error',
  },
}

module.exports = config