factory-function-composition

Factory functions handle dependency injection by composing clients and services, enforcing a universal two-argument signature with resources first and configuration second to improve testability.

Service composition for multiple layered dependencies is structured using multi-dependency factories and explicit option layering, keeping client creation independent of business logic.

Dependency injection improves testability by enabling mocks and isolation, reducing hidden dependencies so services can be created with injected clients and resources in a predictable way.

Mocking services is done by using factory functions to wire clients and method options, allowing dependencies to be injected independently and easily mocked for testing.

Yes, factory functions support multiple dependencies and explicit option layering through a universal two-argument signature, taking resources as the first argument and configuration as the second.