Javascirpt Battery Status Browser API

battery.js

function updateChargeInfo(battery) {
    var message = battery.charging ? "Charging now :D": "Need Charge" ;
    var batteryStatusNode = document.querySelector('.charging-status');
    var classes = batteryStatusNode.classList;
    document.querySelector('#message').innerHTML =message;
    if(battery.charging) {
        if (classes.contains('charging') === false) {
             classes.add('charging');
            classes.remove('not-charging');
        }
    } else {
            classes.remove('charging');
            classes.add('not-charging');
    }
}



navigator.getBattery().then(battery => {
 updateChargeInfo(battery);   battery.addEventListener('chargingchange', function(){
    updateChargeInfo(battery);
  });
})