---
title: Respect Feature Module Boundaries
impact: CRITICAL
impactDescription: Prevents tight coupling between modules
tags: architecture, boundaries, nestjs, modules
---
## Паспорт документа

- Статус документа: living standard
- Актуально на: 28 марта 2026 года
- Владелец: backend/platform-команда
- Пересмотр: при изменении инженерной практики, CI/CD, архитектурных правил или локального workflow
- Область применения: внутренние rule/reference-card документы для инженерной команды
- Связанные документы:
  - [Индекс Agents](../README.md)
  - [Команды разработки](../commands.md)
  - [Инженерные принципы](../../governance/engineering-principles.md)

## Respect Feature Module Boundaries

**Impact: CRITICAL**

NestJS modules must not reach into each other's internals. Cross-module communication happens only through exported services.

**Incorrect (reaching into another module's internals):**

```typescript
// In seller.service.ts — directly importing catalog repository
import { CatalogRepository } from '../catalog/repositories/catalog.repository';

@Injectable()
export class SellerService {
  constructor(private catalogRepo: CatalogRepository) {} // Wrong!
}
```

**Correct (using exported service from another module):**

```typescript
// In catalog.module.ts — explicitly export what other modules need
@Module({
  providers: [CatalogService, CatalogRepository],
  controllers: [CatalogController],
  exports: [CatalogService], // Only export the service
})
export class CatalogModule {}

// In seller.module.ts — import the module
@Module({
  imports: [CatalogModule],
  providers: [SellerService],
})
export class SellerModule {}

// In seller.service.ts — use the exported service
@Injectable()
export class SellerService {
  constructor(private catalogService: CatalogService) {} // Correct!
}
```

**Rules:**
- Modules only expose services, never repositories or internal DTOs
- Import modules, not individual providers from other modules
- If two modules need heavy cross-communication, consider merging them or extracting shared logic into a separate module