React Error Boundaries

Error Boundaries catch errors in component tree and show fallback UI.

Creating Error Boundary

class ErrorBoundary extends React.Component {
  constructor(props) {
    super(props);
    this.state = { hasError: false };
  }

  static getDerivedStateFromError(error) {
    return { hasError: true };
  }

  componentDidCatch(error, errorInfo) {
    console.log('Error:', error, errorInfo);
  }

  render() {
    if (this.state.hasError) {
      return <h1>Something went wrong.</h1>;
    }

    return this.props.children;
  }
}

Using It

function App() {
  return (
    <ErrorBoundary>
      <MyComponent />
    </ErrorBoundary>
  );
}

Multiple Boundaries

<ErrorBoundary>
  <Header />
  <ErrorBoundary>
    <Content />
  </ErrorBoundary>
  <Footer />
</ErrorBoundary>

Remember

• Must be class component
• Catches render errors
• Shows fallback UI
• Doesn't catch event handler errors

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