standards-typescript

TypeScript Coding Standards

Core Principles

1. Simplicity: Simple, understandable code
2. Readability: Readability over cleverness
3. Maintainability: Code that's easy to maintain
4. Testability: Code that's easy to test
5. DRY: Don't Repeat Yourself - but don't overdo it

General Rules

• Early Returns: Use early returns to avoid nesting
• Descriptive Names: Meaningful names for variables and functions
• Minimal Changes: Only change relevant code parts
• No Over-Engineering: No unnecessary complexity
• Minimal Comments: Code should be self-explanatory. No redundant comments!

Naming Conventions

Element	Convention	Example
Variables/Functions	camelCase	getUserById, isActive
Classes/Interfaces/Types	PascalCase	UserService, ApiClient
Constants	UPPER_SNAKE_CASE	MAX_RETRY_COUNT
Private	Prefix with _ or #	_internalMethod, #privateField
Files	kebab-case or camelCase	user-service.ts, userService.ts
Interfaces	No I prefix	User not IUser
Type aliases	PascalCase	UserId, HttpMethod
Event Handlers	Prefix with handle	handleClick, handleSubmit

Project Structure

myproject/
├── src/
│   ├── index.ts              # Entry point
│   ├── config.ts             # Settings, env vars
│   ├── types/
│   │   └── index.ts          # Shared types
│   ├── models/
│   │   └── user.ts           # Domain models
│   ├── services/
│   │   └── user-service.ts   # Business logic
│   ├── repositories/
│   │   └── user-repo.ts      # Data access
│   └── utils/
│       └── helpers.ts        # Utility functions
├── tests/
│   ├── services/
│   │   └── user-service.test.ts
│   └── setup.ts
├── package.json
├── tsconfig.json
└── README.md

Code Style

// Use explicit types for function parameters and return values
function getUserById(userId: string): User | undefined {
  if (!userId) {
    throw new Error("userId cannot be empty");
  }
  // implementation...
}

// Prefer interfaces for object shapes
interface User {
  id: string;
  name: string;
  email: string;
  age?: number;
}

// Use type aliases for unions, intersections, or primitives
type UserId = string;
type HttpMethod = "GET" | "POST" | "PUT" | "DELETE";
type Result<T> = { success: true; data: T } | { success: false; error: string };