nestjs-patterns

# NestJS Development Patterns Production-grade NestJS patterns for modular TypeScript backends. ## When to Activate - Building NestJS APIs or services - Structuring modules, controllers, and providers - Adding DTO validation, guards, interceptors, or exception filters - Configuring environment-aware settings and database integrations - Testing NestJS units or HTTP endpoints ## Project Structure ```text src/ ├── app.module.ts ├── main.ts ├── common/ │ ├── filters/ │ ├── guards/ │ ├── interceptors/ │ └── pipes/ ├── config/ │ ├── configuration.ts │ └── validation.ts ├── modules/ │ ├── auth/ │ │ ├── auth.controller.ts │ │ ├── auth.module.ts │ │ ├── auth.service.ts │ │ ├── dto/ │ │ ├── guards/ │ │ └── strategies/ │ └── users/ │ ├── dto/ │ ├── entities/ │ ├── users.controller.ts │ ├── users.module.ts │ └── users.service.ts └── prisma/ or database/ ``` - Keep domain code inside feature modules. - Put cross-cutting filters, decorators, guards, and interceptors in `common/`. - Keep DTOs close to the module that owns them. ## Bootstrap and Global Validation ```ts async function bootstrap() { const app = await NestFactory.create(AppModule, { bufferLogs: true }); app.useGlobalPipes( new ValidationPipe({ whitelist: true, forbidNonWhitelisted: true, transform: true, transformOptions: { enableImplicitConversion: true }, }), ); app.useGlobalInterceptors(new ClassSerializerI...