React is a JavaScript library developed by Facebook for building user interfaces using reusable components and a virtual DOM for efficient rendering.

What are React hooks?

Hooks are functions that allow you to use state and lifecycle features in functional components. Common hooks include useState, useEffect, useContext, and useReducer.

What is the virtual DOM?

The virtual DOM is an in-memory representation of the real DOM. React uses it to determine what changes need to be made and updates only those parts in the actual DOM efficiently.

React.js Interview Questions

351. How do React applications degrade during partial backend outages?

352. How would you build resilient recovery flows for React frontends?

353. What retry and fallback strategies improve React application resilience?

354. How do Suspense and error boundaries cooperate during failures?

355. How would you architect resilient loading-state systems in React?

356. How do React applications behave under network instability?

357. How would you design offline-first React systems?

358. How do service workers integrate with React rendering lifecycles?

359. What stale-cache risks occur in React PWAs?

360. How would you safely update offline-capable React applications?