Hands-On Design Patterns with Swift

Leveraging extensions

In Swift, any class, struct, or protocol can be extended. In this case, we can improve implementation of the adapter pattern for MixpanelInstance by using an extension, as follows:

extension MixpanelInstance: Tracking {    func record(event: String, properties: [String : String]?) {        track(event: event, properties: properties)    }}

With this pattern, there is no need to create a wrapper instance and forward implementation calls in the wrapper. Depending on your code base, use case, and particularities, you may find it easier to use extensions over wrapping as a method:

let tracker: Trackingif USE_FIREBASE {    tracker = FirebaseTrackingAdapter()} else  {    tracker = Mixpanel.mainInstance()}Tracker.shared.set(trackingAdapter: tracker) ...