# Rules (short):
# - Avoid generic names (helpers, misc, data)
# - Use role suffixes (*.service.ts, *.controller.ts, *.repository.ts)
# - camelCase for code, PascalCase for types, UPPER_CASE for constants
# - Mirror source path in tests (tests/ mirrors src/)

TypeScript/JavaScript:
├── PascalCase.tsx       # React components
├── camelCase.ts         # Utilities, services
├── kebab-case.ts        # Config, scripts
├── UPPERCASE.md         # Documentation

Suffixes:
├── *.service.ts         # Service classes
├── *.controller.ts      # API controllers
├── *.repository.ts      # Data access
├── *.middleware.ts      # Middleware
├── *.dto.ts             # Data transfer objects
├── *.types.ts           # Type definitions
├── *.test.ts            # Unit tests
├── *.spec.ts            # Integration tests
├── *.e2e.ts             # End-to-end tests
├── *.mock.ts            # Mock implementations
├── *.config.ts          # Configuration
├── *.constants.ts       # Constants

Structure:
src/
├── api/                 # Singular domain folders
├── domain/
│   ├── users/          # Feature/entity folders
│   ├── orders/
│   └── products/
├── infrastructure/
├── shared/
│   ├── utils/          # Utility folders
│   ├── types/
│   └── constants/
└── __tests__/           # Test folders (double underscore)

Rules:
- Use kebab-case for folders
- Singular for domains (user not users)
- Plural for collections (utils, types)
- Max 4 levels deep
- No generic names (helpers, misc, stuff)

// Variables: camelCase
const userId = 'user123';
const isActive = true;
const userList = [];

// Constants: SCREAMING_SNAKE_CASE
const MAX_RETRY_COUNT = 3;
const API_BASE_URL = 'https://api.example.com';

// Functions: camelCase with verb prefix
function getUserById(id: string) {}
function createUser(data: UserInput) {}
function validateEmail(email: string) {}
function handleUserUpdate(event: Event) {}

// Boolean: is/has/can/should prefix
function isValid(input: string) {}
function hasPermission(user: User) {}
function canDelete(item: Item) {}

// Async: consider suffix
function fetchUserAsync() {}
function getUserPromise() {}

// Interfaces: PascalCase with 'I' prefix (optional)
interface User {}
interface IUserRepository {}  // Optional I prefix

// Types: PascalCase
type UserId = string;
type UserRole = 'admin' | 'user';

// Enums: PascalCase, members SCREAMING_SNAKE_CASE
enum UserStatus {
  ACTIVE = 'active',
  INACTIVE = 'inactive',
  PENDING = 'pending',
}

// DTOs: PascalCase with Dto suffix
interface CreateUserDto {}
interface UpdateUserDto {}

// Response/Request types
interface GetUserResponse {}
interface CreateUserRequest {}

// Test files: mirror source path
// src/services/UserService.ts
// → tests/services/UserService.test.ts

// Test names: describe what, when, expect
describe('UserService', () => {
  describe('createUser', () => {
    it('should create user when valid data provided', () => {});
    it('should throw error when email invalid', () => {});
    it('should hash password before saving', () => {});
  });
});

// Test helpers: .mock.ts, .fixture.ts
// tests/__mocks__/UserService.mock.ts
// tests/__fixtures__/users.fixture.ts

// .eslintrc.js
{
  "rules": {
    "@typescript-eslint/naming-convention": [
      "error",
      { "selector": "variable", "format": ["camelCase", "UPPER_CASE"] },
      { "selector": "function", "format": ["camelCase"] },
      { "selector": "typeLike", "format": ["PascalCase"] }
    ]
  }
}