Hands-On Design Patterns with Swift

Checklist for using the factory method pattern

Before you start adding this pattern everywhere in your code, you need to understand that it solves certain issues, so it's helpful to encounter (and suffer from) those first.

The main use of this pattern is to ensure you do not need to write platform-specific code in your application, and that you keep those pesky #available and os() checks (or other compile time or runtime checks) hidden from the consumer.

1. First, ensure you have platform-specific code you need to abstract away (iOS vs tvOS, or iOS 9.0 vs iOS 12.0).
2. Define a common interface for the platform-specific objects, as we did with PushNotificationService and UserLocationService.
3. Implement platform-specific classes for each interface, ...