Hands-On Design Patterns with Swift

Protocol extensions

We can leverage protocol extensions to provide default implementations for our protocols. 

Let's go back to where we were before implementing this whole inheritance chain:

protocol ServicesFactoryType {    func getPushService() -> PushNotificationService    func getUserLocationService() -> UserLocationService    /* Add more services here as your project grows */}

We can just extend that protocol, as follows:

extension ServicesFactoryType {    func getUserLocationService() -> UserLocationService {        return CommonUserLocationService()    }}

We're done—no additional changes, no override keyword to add to the implementations. This strategy has one major drawback, however, compared to the inheritance strategy. In the specific iOS and macOS ...