I started with error boundaries and felt pretty good about componentDidCatch and getDerivedStateFromError, but then I kind of fumbled when they pushed on async event handlers.
Start by categorizing errors into render-time and async, then describe a layered strategy: error boundaries for render errors, try/catch and global handlers for async, and centralized logging with user-friendly fallbacks. Emphasize trade-offs like granularity vs. simplicity and how you'd tailor the approach to Apple's high-quality standards.
Pro tip: Show you understand that error boundaries don't catch async errors, and mention how you'd use React 18's useErrorBoundary or libraries like react-error-boundary to bridge that gap. Also, discuss how you'd prevent errors from reaching users in production by using error monitoring tools like Sentry and implementing graceful degradation.
Distinguish between render-time errors (e.g., in component lifecycle) and async errors (e.g., API calls, event handlers). This sets the stage for different handling mechanisms.
Use React error boundaries to catch errors during rendering, in lifecycle methods, and in constructors. Place them strategically to isolate failures and show fallback UI.
Wrap async operations in try/catch blocks, and use window.addEventListener('unhandledrejection') and 'error' for uncaught exceptions. Consider using a centralized error handler service.
Integrate error logging tools (e.g., Sentry, LogRocket) to capture errors with context. Ensure sensitive data is scrubbed and errors are reported in real-time.
Display user-friendly error messages, offer retry mechanisms, and gracefully degrade functionality. For critical errors, consider redirecting to a safe state.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Suspense for data fetching is one of those things I understand conceptually but explaining the error integration got messy.
Start by clarifying the distinction between error boundaries (for runtime errors) and Suspense (for async loading states), then propose a layered fallback strategy that composes both. Emphasize how to design fallbacks that are resilient, accessible, and provide graceful degradation without disrupting the rest of the app.
Pro tip: Show that you consider the user experience during failures—e.g., offering a retry action, preserving layout stability, and logging errors—rather than just technical implementation. Apple values attention to detail and seamless experiences even in failure modes.
Explain that error boundaries catch JavaScript errors in a subtree and render a fallback UI, while Suspense handles async operations (like data fetching or code splitting) by showing a fallback until the operation resolves. They solve different problems but can be composed.
Describe the fallback UI: it should be minimal, accessible, and provide clear feedback (e.g., a message, retry button, or skeleton). Consider whether to show a full-page fallback or a localized one that preserves surrounding layout.
Explain how to wrap the subtree with both an error boundary and Suspense. The error boundary catches errors, while Suspense shows a loading fallback. Ensure the error boundary is outside Suspense so it can catch errors from the async component.
Discuss strategies for recovery: e.g., a retry button that resets the error boundary state, or using a key change to remount the subtree. Also mention logging errors to a monitoring service.
Talk about trade-offs: granularity of error boundaries (too many vs. too few), performance impact of fallbacks, and how to avoid cascading failures. Mention that Suspense fallbacks should be designed to avoid layout shifts.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
Start by outlining a layered strategy: capture errors globally, enrich them with context, and route them to a service like Sentry while filtering noise. Then explain what specific data you send (stack traces, breadcrumbs, user/session context) and how you use it to prioritize fixes. Finally, tie it to a feedback loop with monitoring dashboards and alerting.
Pro tip: Emphasize privacy and performance: scrub PII before sending, sample high-volume errors, and use Sentry's release tracking to correlate errors with deployments. This shows you balance observability with user trust and app performance.
Set up global handlers for uncaught exceptions and unhandled promise rejections, plus framework-specific error boundaries (e.g., React) to catch rendering errors.
Attach useful metadata: user ID (anonymized), session ID, app version, release, environment, device/browser info, and breadcrumbs of user actions leading to the error.
Ignore known noise (e.g., browser extensions, network errors) and sample high-volume errors to control cost and noise. Use Sentry's beforeSend to scrub PII and drop irrelevant events.
Configure Sentry SDK to send errors with source maps for readable stack traces, and set up release tracking to associate errors with specific deployments.
Use Sentry's dashboards and alerts to track error rates, prioritize by impact, and integrate with issue trackers. Close the loop by fixing and verifying via release health.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.