ReactJS componentDidCatch() Method

componentDidCatch() is a React lifecycle method used to handle errors in child components and prevent the entire app from crashing. It also allows side-effects like logging errors during the commit phase.

• Catches rendering errors in child components or lifecycle methods.
• Enables creation of Error Boundaries for graceful UI fallback.
• Allows logging errors to external monitoring services.
• Supports side-effects safely since it runs after the render phase.

Syntax:

componentDidCatch(error, info)

Parameters: It accepts two parameters i.e, error, and info as described below:

• error: It is the error that was thrown by the descendant component.
• info: It stores the componentStack trace of which component has thrown this error.

Creating React Application:

Step 1: Create a React application using the following command:

npx create-react-app foldername

Step 2: After creating your project folder i.e. folder name, move to it using the following command:

cd foldername

Project Structure: It will look like the following.

Example: Program to demonstrate the use of componentDidCatch() method.

Filename: App.js:  

import React, { Component } from 'react';

export default class App extends Component {
  // Initializing the state
  state = {
    error: false,
  };

  componentDidCatch(error) {
    // Changing the state to true 
    // if some error occurs
    this.setState({
      error: true
    });
  }

  render() {
    return (
      <React.StrictMode>
        <div>
          {this.state.error ? <div>Some error</div> : <GFGComponent />}
        </div>
      </React.StrictMode>
    );
  }
}

class GFGComponent extends Component {

  // GFGComponent throws error as state of 
  // GFGCompnonent is not defined
  
  render() {
    return <h1>{this.state.heading}</h1>;
  }
}

Step to Run Application: Run the application using the following command from the root directory of the project:

npm start

Output:

Reference: https://legacy.reactjs.org/docs/react-component.html#componentdidcatch