service-layer-extractor

To refactor fat controllers into a service layer, you extract business logic out of route handlers into dedicated services, establishing clear boundaries and dependency injection. This provides service interfaces, folder structures, and migration plans for architectural cleanup.

Separating business logic from route handlers for better testability involves moving it into a dedicated service layer. This enables unit testing of business logic independently of HTTP concerns and manages dependencies through injection.

Business logic centralization in API endpoints causes maintainability issues because it creates god objects that mix HTTP concerns with core rules. Extracting these rules into a service layer with clear boundaries resolves this architectural debt.

Yes, refactoring to a service layer includes a migration plan and folder structure. It provides structured approaches to divide responsibilities between routes, controllers, services, and repositories during architectural cleanup.

You need to introduce dependency injection when your route handlers contain significant business logic, making them hard to read and test. Moving logic into a service layer facilitates managing and injecting dependencies for cleaner code.