Virtualization: Use libraries like react-window or react-virtualized to only render?

Short answer: the items that are visible in the viewport. Example of list optimization with key: const List = ({ items }) => { return ( <ul> {items.map(item => ( <li key={item.id}>{item.name}</li> ))} </ul> ); };

Real-world example (ShopNest)

ShopNest’s storefront is React: components for ProductCard, CartDrawer, and CheckoutForm, with hooks for local UI state.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.