Full Stack Development

In React 18, what mechanism allows multiple state updates in a component to be batched even across asynchronous boundaries?

• useDeferredValue

• useEffect

• Automatic Batching

• useTransition

In React Native, how does FlatList handle large datasets optimally?

• Pre-renders all rows

• Virtualization

• Lazy loading from server

• Memoization

Which method in Next.js pre-renders a page on the server for every request?

• getStaticProps

• getServerSideProps

• getInitialProps

• useEffect

What feature of Next.js improves SEO and load time for dynamic content?

• Dynamic Imports

• ISR (Incremental Static Regeneration)

• Code Splitting

• Hydration

What causes hydration mismatch in a React + Next.js app?

• Unused CSS

• Different server and client renders

• Lazy loading issues

• State updates during build time

What is the effect of setting process.env.UV_THREADPOOL_SIZE to 64?

• Increases CPU core usage

• Increases libuv thread pool size

• Decreases async call performance

• Reserves memory

In Express.js, middleware order affects:

• HTTP response size

• Request processing sequence

• Server port assignment

• Error boundary activation

What is the consequence of calling next() twice in the same Express middleware?

• Server crashes

• Skips middleware

• Response is sent twice

• Middleware ignored

How can Express route performance be improved in a high traffic app?

• Disabling gzip

• Using memory store for sessions

• Compression + Redis caching

• Disabling CORS

What does the cluster module in Node.js help with?

• Database scaling

• Redis sharding

• CPU core utilization

• Memory cache sharing