Useful Javascript function

This is the javascript function that allow you to check if the internet connection is available or not. Simply call this function will return true or false.

navigator.onLine

import React, { useState, useEffect } from 'react';

const Online = () => {

    const [mode, setMode] = useState(navigator.onLine);

    useEffect(() => {
        window.addEventListener('online', handleNetwork);
        window.addEventListener('offline', handleNetwork);

        // componentDidMount() 
        // componentDidUpdate()
        // componentWillUnMount()
        return () => {
            window.removeEventListener('online', handleNetwork);
            window.removeEventListener('offline', handleNetwork);
        }
    }, [mode]); // value inside array will execute everytime after effect


    const handleNetwork = (event) => {
        setMode(!mode);
    };

    return (
        <div>
            <h1>Online status</h1>
            <p> Mode: {mode ? "online" : "offline"} </p>
        </div>
    );
};

export default Online;