While working in React, have you encountered React error boundary messages? How do you handle them?

React error boundaries are components that catch JavaScript errors in their child component tree, log them, and display a fallback UI. To handle them, create a class component with componentDidCatch(error, info) and a state flag. In render, if an error occurred, return a fallback UI; otherwise, render children. Wrap high‑level components (e.g., pages or feature modules) with the error boundary so that a failure in one part doesn’t crash the whole app. Log the error to an external service (Sentry, LogRocket). Test by throwing an error in a child component and verifying the fallback renders. For functional components, use the useErrorHandler hook from react-error-boundary or a custom hook that mimics the lifecycle.