A service instance can be used by components that need to communicate to each other or share a common state. If these two components originate from different code bases, e.g. are deployed via plugin-ins, then hookService comes as a way for such a shared service to be injected. The service interface might be declared in a shared library known at compile time.

This example showcases two component instances that share a counter service. The counter service interface is declared in the counder.model module which may be declared in a common library shared between plug-ins in a real world case. The CounterHookModule leverages hookService to inject a service instance. This can happen in a plugin or in a shell application.