Error Handling Interview Questions
Comprehensive error handling interview questions and answers for React JS. Prepare for your next job interview with expert guidance.
Questions Overview
1. What are Error Boundaries in React and why are they used?
Basic2. How do you implement an Error Boundary component?
Moderate3. What types of errors can't be caught by Error Boundaries?
Moderate4. How do you handle errors in event handlers?
Basic5. What are the best practices for error reporting in React?
Moderate6. How do you handle async errors in React components?
Moderate7. What is the role of componentDidCatch lifecycle method?
Moderate8. How do you implement error recovery mechanisms?
Advanced9. What are the patterns for handling network errors?
Moderate10. How do you handle errors in React hooks?
Advanced11. What are the strategies for handling form validation errors?
Moderate12. How do you handle errors in Redux/state management?
Advanced13. What are the best practices for error boundary placement?
Advanced14. How do you handle errors in React Suspense?
Advanced15. What are the patterns for error handling in HOCs?
Advanced16. How do you handle errors in React portals?
Advanced17. What are the strategies for handling initialization errors?
Moderate18. How do you implement graceful degradation in error scenarios?
Advanced19. What are the patterns for handling route errors?
Moderate20. How do you handle errors in server-side rendering?
Advanced21. What are the best practices for error message design?
Basic22. How do you handle memory leaks and cleanup errors?
Advanced23. What are the patterns for handling validation errors in forms?
Moderate24. How do you handle errors in data fetching?
Moderate25. What are the strategies for error monitoring in production?
Advanced26. How do you handle errors in third-party components?
Moderate27. What are the patterns for handling authentication errors?
Moderate28. How do you implement error tracking and analytics?
Advanced29. What are the best practices for testing error scenarios?
Advanced1. What are Error Boundaries in React and why are they used?
BasicError Boundaries are React components that catch JavaScript errors in their child component tree and display fallback UI. They prevent the entire app from crashing and provide a way to gracefully handle runtime errors.
2. How do you implement an Error Boundary component?
ModerateCreate a class component that implements either getDerivedStateFromError() or componentDidCatch() lifecycle methods. getDerivedStateFromError() renders fallback UI, while componentDidCatch() handles error logging.
3. What types of errors can't be caught by Error Boundaries?
ModerateError Boundaries don't catch errors in event handlers, asynchronous code (setTimeout/requestAnimationFrame), server-side rendering, or errors thrown in the error boundary itself. These require different error handling approaches.
4. How do you handle errors in event handlers?
BasicUse try-catch blocks in event handlers, implement proper error handling and state updates, provide user feedback. Consider global error handling for uncaught errors in events.
5. What are the best practices for error reporting in React?
ModerateImplement proper error logging services, collect relevant error context, handle different error types appropriately, maintain user privacy. Consider environment-specific logging strategies.
6. How do you handle async errors in React components?
ModerateUse try-catch with async/await, implement proper error states, handle promise rejections, use error boundaries where applicable. Consider loading states and user feedback.
7. What is the role of componentDidCatch lifecycle method?
ModeratecomponentDidCatch captures error information and error stack traces. Used for error logging, analytics, and side effects in error handling. Cannot modify state during render phase.
8. How do you implement error recovery mechanisms?
AdvancedImplement retry logic, state reset mechanisms, fallback UI, and proper error clearing. Consider user experience and recovery workflows.
9. What are the patterns for handling network errors?
ModerateImplement proper error status handling, retry mechanisms, offline detection, and user feedback. Consider caching strategies and fallback content.
10. How do you handle errors in React hooks?
AdvancedUse try-catch in effects, implement error states, handle cleanup properly, consider custom hooks for error handling. Cannot use error boundaries directly in hooks.
11. What are the strategies for handling form validation errors?
ModerateImplement client-side validation, handle server validation errors, provide clear error messages, manage error states properly. Consider UX and accessibility.
12. How do you handle errors in Redux/state management?
AdvancedImplement error reducers, handle async action errors, provide error states in store, consider middleware for error handling. Handle global vs local error states.
13. What are the best practices for error boundary placement?
AdvancedPlace boundaries strategically to isolate failures, consider component hierarchy, implement granular error handling. Balance between too many and too few boundaries.
14. How do you handle errors in React Suspense?
AdvancedUse Error Boundaries with Suspense, handle loading errors, implement fallback UI, manage timeout scenarios. Consider data fetching errors.
15. What are the patterns for error handling in HOCs?
AdvancedImplement error handling logic in HOCs, wrap components with error boundaries, handle prop validation errors. Consider composition of error handling HOCs.
16. How do you handle errors in React portals?
AdvancedUse error boundaries around portals, handle portal-specific errors, manage cleanup on errors. Consider modal and overlay error scenarios.
17. What are the strategies for handling initialization errors?
ModerateHandle app bootstrap errors, implement fallback content, manage configuration errors, provide meaningful error messages. Consider recovery options.
18. How do you implement graceful degradation in error scenarios?
AdvancedProvide fallback functionality, implement feature detection, handle browser compatibility issues. Consider progressive enhancement approaches.
19. What are the patterns for handling route errors?
ModerateImplement route-level error boundaries, handle navigation errors, provide error pages, manage route transitions. Consider deep linking errors.
20. How do you handle errors in server-side rendering?
AdvancedImplement SSR-specific error handling, manage hydration errors, handle state reconciliation issues. Consider client-server error differences.
21. What are the best practices for error message design?
BasicProvide clear, actionable error messages, implement proper i18n, consider user experience, maintain consistency. Handle different error types appropriately.
22. How do you handle memory leaks and cleanup errors?
AdvancedImplement proper cleanup in useEffect, handle component unmounting, manage resource disposal. Consider async operation cancellation.
23. What are the patterns for handling validation errors in forms?
ModerateImplement field-level and form-level validation, handle async validation, provide immediate feedback. Consider UX and accessibility requirements.
24. How do you handle errors in data fetching?
ModerateImplement proper error states, handle network failures, manage retry logic, provide user feedback. Consider caching and offline scenarios.
25. What are the strategies for error monitoring in production?
AdvancedImplement error tracking services, collect error metrics, analyze error patterns, set up alerts. Consider privacy and performance implications.
26. How do you handle errors in third-party components?
ModerateWrap third-party components in error boundaries, handle integration errors, implement fallbacks. Consider version compatibility issues.
27. What are the patterns for handling authentication errors?
ModerateHandle session expiration, implement token refresh, manage unauthorized access, provide proper user feedback. Consider security implications.
28. How do you implement error tracking and analytics?
AdvancedIntegrate error tracking services, collect relevant error data, implement proper error categorization. Consider privacy and compliance requirements.
29. What are the best practices for testing error scenarios?
AdvancedTest error boundaries, simulate different error conditions, verify error recovery, implement comprehensive test cases. Consider edge cases and error combinations.