CODE EXAMPLE FOR JAVASCRIPT

react click outside class implementation

import React, { Component } from 'react';
import PropTypes from 'prop-types';

/**
 * Component that alerts if you click outside of it
 */
export default class OutsideAlerter extends Component {
    constructor(props) {
        super(props);

        this.wrapperRef = React.createRef();
        this.setWrapperRef = this.setWrapperRef.bind(this);
        this.handleClickOutside = this.handleClickOutside.bind(this);
    }

    componentDidMount() {
        document.addEventListener('mousedown', this.handleClickOutside);
    }

    componentWillUnmount() {
        document.removeEventListener('mousedown', this.handleClickOutside);
    }

    /**
     * Alert if clicked on outside of element
     */
    handleClickOutside(event) {
        if (this.wrapperRef && !this.wrapperRef.current.contains(event.target)) {
            alert('You clicked outside of me!');
        }
    }

    render() {
        return <div ref={this.wrapperRef}>{this.props.children}</div>;
    }
}

OutsideAlerter.propTypes = {
    children: PropTypes.element.isRequired,
};