text: import React from 'react';
  
  class ErrorBoundary extends React.Component {
    constructor(props) {
      super(props);
      this.state = { error: null, errorInfo: null };
    }
  
    componentDidCatch(error, errorInfo) {
      // Catch errors in any components below and re-render with error message
      this.setState({
        error: error,
        errorInfo: errorInfo,
      });
      // You can also log error messages to an error reporting service here
    }
  
    render() {
      if (this.state.errorInfo) {
        // Error path
        return (
          <div>
            <h2>Something went wrong.</h2>
            <details style={{ whiteSpace: 'pre-wrap' }}>
              {this.state.error && this.state.error.toString()}
              <br />
              {this.state.errorInfo.componentStack}
            </details>
          </div>
        );
      }
      // Normally, just render children
      return this.props.children;
    }
  }
  
  class BuggyCounter extends React.Component {
    constructor(props) {
      super(props);
      this.state = { counter: 0 };
      this.handleClick = this.handleClick.bind(this);
    }
  
    handleClick() {
      this.setState(({ counter }) => ({
        counter: counter + 1,
      }));
    }
  
    render() {
      if (this.state.counter === 5) {
        // Simulate a JS error
        throw new Error('I crashed!');
      }
      return <h1 onClick={this.handleClick}>{this.state.counter}</h1>;
    }
  }
  
  function App() {
    return (
      <div>
        <p>
          <b>
            This is an example of error boundaries in React 16.
            <br />
            <br />
            Click on the numbers to increase the counters.
            <br />
            The counter is programmed to throw when it reaches 5. This simulates a
            JavaScript error in a component.
          </b>
        </p>
        <hr />
        <ErrorBoundary>
          <p>
            These two counters are inside the same error boundary. If one crashes,
            the error boundary will replace both of them.
          </p>
          <BuggyCounter />
          <BuggyCounter />
        </ErrorBoundary>
        <hr />
        <p>
          These two counters are each inside of their own error boundary. So if
          one crashes, the other is not affected.
        </p>
        <ErrorBoundary>
          <BuggyCounter />
        </ErrorBoundary>
        <ErrorBoundary>
          <BuggyCounter />
        </ErrorBoundary>
      </div>
    );
  }
  
  export default App;
  