Nestjs API

Iron Law

NO NESTJS MODULE WITHOUT READING reference/nestjs-conventions.md FIRST — Fastify adapter quirks, Prisma 7.x patterns, and DTO validation rules are defined there

NestJS 11.x + Fastify + Prisma REST API Skill

Conventions & Rules

For code conventions, package layout, NestJS rules, Prisma 7.x rules, and environment file rules, read reference/nestjs-conventions.md

Quick Scaffold — New NestJS Project

# Using NestJS CLI
npx @nestjs/cli new my-service --package-manager npm --strict

Process

1. Scaffold using NestJS CLI or the command above
2. Configure package.json and tsconfig — read reference/nestjs-config-basics.md, reference/nestjs-config-npm-ts.md, and reference/nestjs-config-prisma7.md
3. Create files using templates — read reference/nestjs-templates-core.md for main.ts, AppModule, CoreModule; read reference/nestjs-templates-features.md for feature modules, controllers, services, DTOs
4. Follow conventions below for package layout and NestJS rules
5. Write tests with Vitest + supertest or NestJS Testing utilities
6. Format and check: npm run lint && npm run typecheck

Key Patterns

Reference Files

Common Commands

npm run start:dev                           # Run in dev mode (watch)
npm test                                    # Run unit tests (Vitest)
npm run test:e2e                            # Run integration/E2E tests
npm run test:cov                            # Run tests with coverage report
npm run lint                                # ESLint check
npm run typecheck                           # TypeScript type-check only
npm run build                               # Compile TypeScript
npx prisma migrate dev --name <migration>   # Create and run migration
npx prisma generate                         # Regenerate Prisma client after schema change
npx prisma studio                           # Open Prisma Studio GUI

Documentation Sources

Before generating code, consult these sources for current syntax and APIs:

Error Handling

Validation errors: Use class-validator decorators on DTO classes. Global ValidationPipe auto-returns 422 with details.

Not-found errors: Throw NotFoundException from services. Global exception filter returns structured 404.

Duplicate errors: Catch Prisma P2002 unique constraint violation and convert to 409 Conflict.

Hard Prohibitions

• No raw any request bodies — all endpoints must use DTOs with class-validator decorators
• No raw SQL unless performance-critical (document why in a comment)
• No jest in new code — use Vitest exclusively
• @UseGuards(JwtAuthGuard) on every non-public route — no exceptions
• No arbitrary Tailwind values (p-[13px]) — use the scale (p-4, gap-6)
• Angular: no *ngIf/*ngFor — use @if/@for/@switch; typed reactive forms FormGroup<T> only

Post-Code Review

After writing TypeScript code, dispatch these reviewer agents:

• nestjs-reviewer — module correctness, Prisma usage, resilience patterns
• code-reviewer — general quality, DRY, error handling
• security-reviewer — auth, input validation, OWASP Top 10