usecase-design

To separate business logic from routers, implement thin routers that delegate operations to dedicated use cases. This modular architecture encapsulates domain rules cleanly, preventing infrastructure coupling and keeping application logic isolated.

The best way to structure modules for domain-driven design is using a prescribed layout: modules/{module}/ containing application/use-cases, domain, and infrastructure layers. This enforces clean separations between presentation, application, and domain logic.

Make use cases testable with dependency injection by defining repository interfaces and injecting dependencies into your use cases. This enables flexible implementations and allows you to swap infrastructure components easily during testing.

Mixing business logic and infrastructure leads to hard-to-test code because tightly coupled routers prevent isolated testing. Encapsulating business rules into use cases with dependency injection solves this by enabling clean separations.

Yes, you can use clean architecture for multi-layer app feature development by encapsulating business rules into use cases and thin routers. It guides module boundaries, dependency injection, and clean separations between presentation, application, and domain logic.