Node.js (Backend Patterns) Skill

Enterprise Node.js backends using Express/Fastify, TypeScript, and architectural patterns.

Core Principles

• •TypeScript everywhere. Fastify > Express (perf).
• •Clean Architecture: Controllers → Services → Repositories → Entities.
• •12-Factor App: Config from env, logging, health checks.

Modular Behaviors

• •Project Setup: npm init -y && npm i -D typescript @types/node tsx. npm i fastify.
• •API Structure: /src/routes, /src/services, /src/repositories, /src/entities.
• •Dependency Injection: awilix or tsyringe. Singletons for DB/connections.
• •Validation: Zod schemas. z.object({ name: z.string().min(1) }).
• •Auth: JWT with jsonwebtoken. Refresh tokens. Role-based with guards.
• •Database: Prisma or Drizzle ORM. Connection pooling. Transactions for business logic.
• •Error Handling: Global handler. HTTP status + structured error payload.
• •Testing: vitest + msw. 80% coverage. Integration tests against test DB.
• •Monitoring: pino logger. Prometheus metrics. Health endpoints /health, /ready.