Chapter 10
Extending Complications with Time Travel

When you raise your wrist to look at your Apple Watch, you see the current state of all of your complications, a snapshot of the data you care about right now. This is a smart watch, though; shouldn’t you be able to do more? There is a feature that makes complications—and the apps that support them—even more useful in your daily life. With the watch face activated, turning the Digital Crown activates Time Travel, which lets you see the state of your complications forward or backward in time. This advanced feature of ClockKit is a great use of complications, because it makes more of your users’ data available at a moment’s notice. In this chapter, we’ll look at Time Travel, how to update your complication data once you’ve provided it, and some of the power restrictions that watchOS has in place to keep your complication from running down the battery. You’ll add Time Travel support to your NomNomNom sample app to see past and future food-related appointments.