This lesson discusses when and how to add dependencies, resolved by Angular’s DI, to factory providers. The example used in this lesson builts upon the previous lesson on understanding factory providers.
In the angular docs states that:
Technically, the @Injectable()decorator is only required for a service class that has its own dependencies.
But in your example, LogDebugger has a dependency on ConsoleService. And works event when you're not using @Inyectable decorator at all.
How is it possible? Or Am I misunderstanding something?