How to detect click outside React component ?

We can use the createRef()  method to create a reference for any element in the class-based component. Then we can check whether click event occurred in the component or outside the component.

In the functional component, we can use the useRef() hook to create a reference for any element.

Creating React Application And Installing Module:

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

npx create-react-app foldername

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

cd foldername

Project Structure: It will look like the following.

App.js: Now write down the following code in the App.js file. Here, App is our default component where we have written our code.

Filename- App.js: Using Class base Component

import React from 'react';
class App extends React.Component {

  constructor(props) {
    super(props);

    // Creating a reference
    this.box = React.createRef();
  }

  componentDidMount() {

    // Adding a click event listener
    document.addEventListener('click', this.handleOutsideClick);
  }

  handleOutsideClick = (event) => {
    if (this.box && !this.box.current.contains(event.target)) {
      alert('you just clicked outside of box!');
    }
  }

  render() {
    return <div style={{
      margin: 300,
      width: 200, height: 200, backgroundColor: 'green'
    }}

      // Assigning the ref to div component
      ref={this.box}>{this.props.children}</div>;
  }
}

export default App;

Filename- App.js:< Using Functional Component/p> JavaScript

import React, { useEffect, useRef } from 'react'

function App(props) {
  const box = useRef(null);
  useOutsideAlerter(box);
  return (<div style={{
    margin: 300,
    width: 200, height: 200, backgroundColor: 'green'
  }}
    ref={box}>{props.children}</div>
  )
}

export default App;

function useOutsideAlerter(ref) {
  useEffect(() => {

    // Function for click event
    function handleOutsideClick(event) {
      if (ref.current && !ref.current.contains(event.target)) {
        alert("you just clicked outside of box!");
      }
    }

    // Adding click event listener
    document.addEventListener("click", handleOutsideClick);
    return () => document.removeEventListener("click", handleOutsideClick);
  }, [ref]);
}

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

npm start

Output: Now open your browser and go to http://localhost:3000/, you will see the following output: