How does an error boundary work in React?

Short answer: An Error Boundary is a React component that catches JavaScript errors in its child components, logs those errors, and displays a fallback UI. This prevents the entire app from crashing when an error occurs in a part of the component tree. Usage:

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.