Make Errors User-Friendly with React Error Boundaries
Tags: react, javascript, webdev, programming
Published: 2022-08-13 16:13:00

# What are Error Boundaries ?

React Error Boundaries are used to show a user-friendly UI to users when unexpected JavaScript errors occur.

A JavaScript error in a part of the UI usually renders a white screen and crashes the entire app. React Version 16 introduced a solution to this issue with the new “Error Boundary” concept.

# How can I implement Error Boundaries ?

You can implement React Error Boundaries in your React app in 2 simple steps

1. Create an error boundary component
2. Wrap error-prone component with error boundary component

## Creating Error Boundary Component

> A class component becomes an error boundary if it defines either (or both) of the lifecycle methods `static getDerivedStateFromError()` or `componentDidCatch()`. Use `static getDerivedStateFromError()` to render a fallback UI after an error has been thrown. Use `componentDidCatch()` to log error information. (https://reactjs.org/docs/error-boundaries.html)

Here is the example error boundary component provided in the React documentation.


```javascript
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;
    }  
  }

export default ErrorBoundary;
``` 

You can create your own error boundary with a fancier UI according to your use case.

## Wrapping with Error Boundary

![wrapping-with-error-boundary](https://media.giphy.com/media/GA1s4aZhfe5f2N3fFb/giphy.gif)

There are two ways you could wrap components with the error boundary

1. You can wrap the top-level component
2. You can wrap individual components

### Wrapping Top-Level Component

```javascript
<ErrorBoundary>
	<App/>
</ErrorBoundary>
``` 

![error-boundaries-for-root](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/qv6xn7ct73ialmg4oywm.gif)
 

### Wrapping Individual Components
This approach would be ideal if your app has multiple different isolated sections.


```javascript
<ErrorBoundary>
	<BankingController/>
</ErrorBoundary>
<ErrorBoundary>
	<ProfileController/>
</ErrorBoundary>
<ErrorBoundary>
	<PolicyController/>
</ErrorBoundary>
``` 

An error occurred in BankingController would not stop user from using the PolicyController or ProfileController.

![error-boundaries-for-individual](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/xx3ep9el45tcl6uvzsub.gif)
 

# So, Is my React app “white screen”-free now?

![wow-image](https://media.giphy.com/media/l3q2K5jinAlChoCLS/giphy.gif)

Well, React error boundaries can catch all errors except for the following :

1. Event Handlers
2. Asynchronous code
3. Server Side Rendering
4. Errors thrown in the error boundary itself

But you can always make use of regular JavaScript try/catch blocks whenever needed.

> As of React 16, errors that were not caught by any error boundary will result in unmounting of the whole React component tree

# Conclusion

React error boundaries provide a way for developers to make our apps more user-friendly. In my opinion, every React app should make use of React error boundaries and it makes a drastic difference in the user experience.

Thank you for taking the time to read my article. Hope you enjoyed it. If you learned something new, make sure to drop a like and share the article with your fellow developers.