In an imperative UI model, the developer is responsible for explicitly managing both application state and UI synchronization.

The UI is treated as a separate entity that must be manually updated in response to state changes.

This typically involves:

• Mutating state
• Determining what changed
• Updating specific UI components accordingly

Example responsibilities:

• Reloading views or components
• Updating labels, images, layouts manually
• Ensuring consistency between data and UI

This leads to:

• Tight coupling between logic and UI updates
• Increased surface area for bugs (missed updates, inconsistent UI state)
• Boilerplate-heavy code (delegates, callbacks, observers)

In essence:

State changes → developer must explicitly update UI

Declarative UI Paradigm (SwiftUI)

In a declarative UI model, the developer defines the UI as a pure function of state.

The framework (SwiftUI) is responsible for: