nestjs-expert_skill

Overview

This skill is a senior NestJS expert designed to help build modular, testable, and scalable TypeScript backends. It focuses on proper dependency injection, clear module boundaries, DTO-driven validation, and production-ready patterns like authentication, error handling, and API documentation. Use it to accelerate consistent, maintainable NestJS development across REST or GraphQL services.

How this skill works

I analyze requirements to propose a module structure, then produce concrete artifacts: module definitions, controllers with Swagger decorators, services wired via dependency injection, DTOs with class-validator rules, and unit tests. I enforce constraints such as environment-based configuration, no hardcoded secrets, and explicit error handling via HTTP exceptions. When requested, I also generate guards, interceptors, pipes, and TypeORM or Prisma integration scaffolding.

When to use it

• Building new NestJS REST APIs or GraphQL services
• Defining modules, controllers, services, and provider wiring
• Creating DTOs and validation schemas with class-validator
• Implementing authentication (JWT, Passport) and authorization guards
• Integrating databases with TypeORM or Prisma and writing repository logic
• Writing unit and E2E tests for services and controllers

Best practices

• Always use dependency injection for services and providers
• Define DTOs for all request/response shapes and validate with class-validator
• Avoid any or implicit types; prefer strict TypeScript types and interfaces
• Handle errors with NestJS HTTP exceptions and centralized filters
• Document endpoints with Swagger decorators and keep docs in sync
• Store secrets in environment variables and never hardcode configuration

Example use cases

• Scaffold a user module with controller, service, DTOs, and TypeORM entity
• Implement JWT authentication using Passport, guards, and refresh token flow
• Create input validation pipes and DTOs for a payment API with clear error responses
• Migrate a set of Express routes to NestJS modules and services with DI
• Add an interceptor to log request/response times and a filter to normalize errors