Component State Management Questions

Covers approaches and patterns for managing user interface state within component-based front end frameworks such as React and Angular. Topics include local component state, lifting state up, one way data flow, controlled versus uncontrolled components, prop passing and change handling, avoiding stale closures and missing dependency arrays, component composition patterns, performance considerations to prevent unnecessary re renders, and when to choose built in mechanisms versus external state libraries. For React this includes hooks such as useState, useContext, useReducer, useCallback, and useMemo and the trade offs of Context versus external stores. For Angular this includes using components and services, dependency injection, reactive programming patterns with observable streams, and change detection strategies. Candidates may be asked to compare state architectures, justify trade offs between simplicity and scalability, refactor components to improve state locality and performance, and design data flow for a feature from user interaction to persistent update.