UIstate

UIstate is the portion of an application's state that directly affects the user interface and user experience. It includes which components are visible, which UI controls are active, and transient values such as form inputs, selections, focus, and loading indicators. UIstate is typically distinct from domain or business state, which models data and rules; UIstate is often ephemeral and tied to a particular user session or view.

Managing UIstate involves local, component-level state and, for shared UI concerns, centralized stores or patterns. Common approaches include local component state (useState or equivalent), lifting state up to parent components, and centralized stores (Redux, Vuex, Zustand, or similar). Some architectures also use route or URL state, and state machines (for example, XState) to model valid UI transitions such as open/close, enabled/disabled, or loading states.

UIstate can be derived from domain state or persisted across sessions by saving preferences. It is typically reset on navigation, refresh, or when the user clears history. Good UIstate management emphasizes explicit transitions, avoids duplicating state, and keeps UI logic separate from business rules. Tests and accessibility considerations are important, as UIstate changes affect how users interact with the app.

Examples include a modal window being open, a tab being selected, a search input's current value, a checkbox's checked state, and a loading spinner indicating ongoing asynchronous work. In practice, designers and developers map UIstate to components and events, ensuring predictable behavior across the application's lifetime.