Nestjs

1---2name: nestjs3description: Provides comprehensive NestJS framework patterns with Drizzle ORM integration for building scalable server-side applications. Generates REST/GraphQL APIs, implements authentication guards, creates database schemas, and sets up microservices. Use when building NestJS applications, setting up APIs, implementing authentication, working with databases, or integrating Drizzle ORM.4allowed-tools: Read, Write, Edit, Glob, Grep, Bash5---6 7# NestJS Framework with Drizzle ORM8 9## Overview10 11Provides NestJS patterns with Drizzle ORM for building production-ready server-side applications. Covers CRUD modules, JWT authentication, database operations, migrations, testing, microservices, and GraphQL integration.12 13## When to Use14 15- Building REST APIs or GraphQL servers with NestJS16- Setting up authentication and authorization with JWT17- Implementing database operations with Drizzle ORM18- Creating microservices with TCP/Redis transport19- Writing unit and integration tests20- Running database migrations with drizzle-kit21 22## Instructions23 241. **Install dependencies**: `npm i drizzle-orm pg && npm i -D drizzle-kit tsx`252. **Define schema**: Create `src/db/schema.ts` with Drizzle table definitions263. **Create DatabaseService**: Inject Drizzle client as a NestJS provider274. **Build CRUD module**: Controller → Service → Repository pattern285. **Add validation**: Use class-validator DTOs with ValidationPipe296. **Implement guards**: Create JWT/Roles guards for route protection307. **Write tests**: Use `@nestjs/testing` with mocked repositories318. **Run migrations**: `npx drizzle-kit generate` → **Verify SQL** → `npx drizzle-kit migrate`32 33## Examples34 35### Complete CRUD Module with Drizzle36 37```typescript38// src/db/schema.ts39export const users = pgTable('users', {40  id: serial('id').primaryKey(),41  name: text('name').notNull(),42  email: text('email').notNull().unique(),43  createdAt: timestamp('created_at').defaultNow(),44});45 46// src/users/dto/create-user.dto.ts47export class CreateUserDto {48  @IsString() @IsNotEmpty() name: string;49  @IsEmail() email: string;50}51 52// src/users/user.repository.ts53@Injectable()54export class UserRepository {55  constructor(private db: DatabaseService) {}56 57  async findAll() {58    return this.db.database.select().from(users);59  }60 61  async create(data: typeof users.$inferInsert) {62    return this.db.database.insert(users).values(data).returning();63  }64}65 66// src/users/users.service.ts67@Injectable()68export class UsersService {69  constructor(private repo: UserRepository) {}70 71  async create(dto: CreateUserDto) {72    return this.repo.create(dto);73  }74}75 76// src/users/users.controller.ts77@Controller('users')78export class UsersController {79  constructor(private service: UsersService) {}80 81  @Post()82  create(@Body() dto: CreateUserDto) {83    return this.service.create(dto);84  }85}86 87// src/users/users.module.ts88@Module({89  controllers: [UsersController],90  providers: [UsersService, UserRepository, DatabaseService],91  exports: [UsersService],92})93export class UsersModule {}94```95 96### JWT Authentication Guard97 98```typescript99@Injectable()100export class JwtAuthGuard implements CanActivate {101  constructor(private jwtService: JwtService) {}102 103  canActivate(context: ExecutionContext) {104    const token = context.switchToHttp().getRequest()105      .headers.authorization?.split(' ')[1];106    if (!token) return false;107    try {108      const decoded = this.jwtService.verify(token);109      context.switchToHttp().getRequest().user = decoded;110      return true;111    } catch {112      return false;113    }114  }115}116```117 118### Database Transactions119 120```typescript121async transferFunds(fromId: number, toId: number, amount: number) {122  return this.db.database.transaction(async (tx) => {123    await tx.update(accounts)124      .set({ balance: sql`${accounts.balance} - ${amount}` })125      .where(eq(accounts.id, fromId));126    await tx.update(accounts)127      .set({ balance: sql`${accounts.balance} + ${amount}` })128      .where(eq(accounts.id, toId));129  });130}131```132 133### Unit Testing with Mocks134 135```typescript136describe('UsersService', () => {137  let service: UsersService;138  let repo: jest.Mocked<UserRepository>;139 140  beforeEach(async () => {141    const module = await Test.createTestingModule({142      providers: [143        UsersService,144        { provide: UserRepository, useValue: { findAll: jest.fn(), create: jest.fn() } },145      ],146    }).compile();147    service = module.get(UsersService);148    repo = module.get(UserRepository);149  });150 151  it('should create user', async () => {152    const dto = { name: 'John', email: 'john@example.com' };153    repo.create.mockResolvedValue({ id: 1, ...dto, createdAt: new Date() });154    expect(await service.create(dto)).toMatchObject(dto);155  });156});157```158 159## Constraints and Warnings160 161- **DTOs required**: Always use DTOs with class-validator, never accept raw objects162- **Transactions**: Keep transactions short; avoid nested transactions163- **Guards order**: JWT guard must run before Roles guard164- **Environment variables**: Never hardcode DATABASE_URL or JWT_SECRET165- **Migrations**: Run `drizzle-kit generate` after schema changes before deploying166- **Circular dependencies**: Use `forwardRef()` carefully; prefer module restructuring167 168## Best Practices169 170- Validate all inputs with global `ValidationPipe`171- Use transactions for multi-table operations172- Document APIs with OpenAPI/Swagger decorators173 174## References175 176Advanced patterns and detailed examples available in:177- `references/reference.md` - Core patterns, guards, interceptors, microservices, GraphQL178- `references/drizzle-reference.md` - Drizzle ORM installation, configuration, queries179- `references/workflow-optimization.md` - Development workflows, parallel execution strategies