Data flow

In SwiftUI, data flow is a key concept for managing how information is shared and propagated throughout an app. Whether we're dealing with local state in a single view or coordinating data across multiple views, SwiftUI provides flexible tools to handle these scenarios.

This chapter explores the different layers of data flow in SwiftUI. We'll start with local view data, move on to managing shared state across views, and then discuss the use of the environment for injecting dependencies. We'll also examine how preferences allow information to flow upward from child views to their parent, complementing the downward flow of the environment. Finally, we'll dive into data persistence, where we discuss how to store data reliably for use across app launches and sessions.

By mastering these data flow mechanisms, we can design SwiftUI apps that are intuitive and maintainable.