nodejs-backend

# Node.js Backend Skill --- ## Project Structure ``` project/ ├── src/ │ ├── core/ # Pure business logic │ │ ├── types.ts # Domain types │ │ ├── errors.ts # Domain errors │ │ └── services/ # Pure functions │ │ ├── user.ts │ │ └── order.ts │ ├── infra/ # Side effects │ │ ├── http/ # HTTP layer │ │ │ ├── server.ts # Server setup │ │ │ ├── routes/ # Route handlers │ │ │ └── middleware/ # Express middleware │ │ ├── db/ # Database │ │ │ ├── client.ts # DB connection │ │ │ ├── repositories/ # Data access │ │ │ └── migrations/ # Schema migrations │ │ └── external/ # Third-party APIs │ ├── config/ # Configuration │ │ └── index.ts # Env vars, validated │ └── index.ts # Entry point ├── tests/ │ ├── unit/ │ └── integration/ ├── package.json └── CLAUDE.md ``` --- ## API Design ### Route Handler Pattern ```typescript // routes/users.ts import { Router } from 'express'; import { z } from 'zod'; import { createUser } from '../../core/services/user'; import { UserRepository } from '../db/repositories/user'; const CreateUserSchema = z.object({ email: z.string().email(), name: z.string().min(1).max(100), }); export function createUserRoutes(userRepo: UserRepository): Router { const router = Router(); router.pos...