Error Boundary Patterns

React error boundary hierarchy and graceful degradation patterns.

Error Boundary Component

// Class-based (React requirement for componentDidCatch)
interface ErrorBoundaryProps {
  children: React.ReactNode
  fallback?: React.ComponentType<FallbackProps>
  onError?: (error: Error, info: React.ErrorInfo) => void
}

interface ErrorBoundaryState {
  error: Error | null
}