How SwiftUI's State management work?

SwiftUI's state management is a key feature that allows views to be state-driven, meaning that when your view's state changes over time, SwiftUI automatically updates the UI. This eliminates the need for boilerplate code and reduces update bugs. SwiftUI maintains a representation of the user interface behind the scenes, and as data changes, new view values are created and used to update the UI.

In SwiftUI, state management is facilitated through several tools:

1. State: This is used to create a new internal source of data for a view. When you mark a view property with @State, SwiftUI manages the storage and provides it back for the view to read and write. For example, a view might use state to keep track of a rating value, which can be incremented or decremented through user interaction.

2. Binding: This creates a two-way reference to the state of another view. It allows a view to read and write to a state that is managed elsewhere, enabling synchronization between views. For instance, a container view might provide a binding to a child view, ensuring that both views reflect the same state.

3. Observable Objects: SwiftUI can track dependencies on specific properties used in view bodies. When these properties change, SwiftUI updates the views that depend on them.

SwiftUI's state management is designed to be declarative, meaning that views are descriptions of what the UI should look like based on the current state, rather than being long-lived object instances that receive imperative commands.

For more detailed information, you can refer to the session SwiftUI essentials (08:50) which covers the fundamentals of views and state management in SwiftUI.