Trusted answers to developer questions
Trusted Answers to Developer Questions

Related Tags


What are Error Boundaries in React?

Fahad Farid

Error boundaries can help catch tricky errors that occur during the rendering phase. This error causes the app to unmount completely, and a blank page to appear.

This method catches JS errors, logs them, and then displays a fallback UI.

svg viewer

Error Boundaries make use of two methods that are already present in the React Components, as follows:

class ErrorBoundary extends Component {
  state = {
    error: null

  static getDerivedStateFromError(error) {
  // Update state so next render shows fallback UI.
  return { error: error };

  componentDidCatch(error, info) {
  // Log the error to an error reporting service
  logErrorToMyService(error, info);

  render() {
    if (this.state.error) {
      // You can render any custom fallback UI
      return <p>There has been an error</p>;
    return this.props.children;

Note: Error boundaries only catch errors in the components below them in the tree, not within themselves.

This method works exactly like the catch{} or the try/except method in that it will propagate to the closest error boundary – the only difference is that it works only for the components.

Note: If an error is not caught by the error boundary, it will cause the whole component to unmount.

import React from 'react';

export default class BuggyCounter extends React.Component {
  constructor(props) {
    this.state = { counter: 1 };
    this.handleClick = this.handleClick.bind(this);
  //increment the counter
  handleClick() {
    this.setState(({counter}) => ({
      counter: counter + 1
  render() {
    //throw error on 5
    if (this.state.counter === 5) {
      throw new Error('Counter Crashed');
    return (
        <h2> {this.state.counter} </h2>
        <button onClick={this.handleClick}> + </button>




Fahad Farid
Copyright ©2022 Educative, Inc. All rights reserved

View all Courses

Keep Exploring