hm-nodejs-business-logic

Place all business logic in a service layer between controllers and repositories. Controllers handle HTTP request/response, services enforce domain rules and call repositories, and repositories encapsulate all Prisma queries.

Create a repository module that wraps Prisma client methods like findUnique, findMany, create, update, and delete behind a clean interface. Services depend on this interface, never importing @prisma/client directly, which makes repositories mockable in tests.

Start with factory functions and constructor injection for simple projects. Move to a DI container like tsyringe or inversify only when manual wiring becomes painful, typically around 10 or more services with cross-dependencies.

No, external API calls should never happen inside a Prisma interactive transaction. Long-running transactions hold database locks, so keep transactions short and move external calls outside the transaction boundary.

Dispatch BullMQ jobs from the service using queue.add with a plain serializable payload, such as sending an order confirmation email after order creation. Services dispatch jobs but never process them; workers handle processing, and jobs should be idempotent.