preserveState

PreserveState is a design concept and set of techniques aimed at maintaining or restoring the state of an application, component, or user session across events that would otherwise cause loss. It covers keeping user input, selections, loading status, scroll position, and partially loaded data intact when an app unloads, a component unmounts, a page reload occurs, or a device orientation change happens. The term appears across mobile, web, and desktop development and is often used as a feature label in frameworks or as a general pattern in state management.

Implementation typically involves either persisting state to durable storage or retaining a live in-memory representation and rehydrating it when needed. Techniques include serializing state to local storage, session storage, or a database; exporting and reloading state through APIs; and using framework-specific lifecycle hooks or state containers to snapshot and restore values. Some environments offer mechanisms to automatically preserve certain parts of the UI when parts of the interface are rebuilt or reconstructed.

Examples span multiple platforms. Mobile applications may save draft data and user preferences to persistent storage to resume later. Web applications sometimes store form inputs in localStorage to survive a page refresh. In certain UI frameworks, components or routes can preserve their internal state when they are reinserted into the interface, or state management libraries coordinate preservation across navigation to maintain continuity.

Key considerations include ensuring consistency between in-memory and persisted representations, the performance impact of persistence operations, privacy and security of stored data, and clear lifecycle rules to avoid stale or conflicting state. A prudent approach often combines essential state preservation with a lean, stateless design for transient data.