NestJS Patterns

Quick Guide: NestJS is an opinionated, modular Node.js framework built on TypeScript. Use modules to organize features, controllers for HTTP routing, services for business logic with dependency injection, DTOs with class-validator for validation, guards for auth, and exception filters for error handling. Key gotchas: always register services in module providers, always enable ValidationPipe globally with whitelist: true, never put business logic in controllers, never instantiate services with new. NestJS 11 is the current stable version (opt-in SWC compiler, Express v5, reversed termination hooks).

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST use @Injectable() on every service and register it in the module providers array)

(You MUST enable ValidationPipe globally with whitelist: true and forbidNonWhitelisted: true)

(You MUST use DTOs with class-validator decorators for ALL request body validation — never validate manually in controllers)

(You MUST throw NestJS built-in HTTP exceptions (NotFoundException, BadRequestException, etc.) — never send raw status codes)