// simple function to create a notification
function notify(bodyTxt) {
  new Notification('Notification Title', {
    body: bodyTxt,
    icon: '/img/favicon.png'
  });
};

switch(Notification.permission) {
  // user previously denied permission
  case "denied":
    window.alert('You denied permission. Please change your browser settings for this page to view notifications');
  // user already has accepted permission
  case "granted":
    notify('You have already granted permission');
    break;
  // should be "default", but catch all anyways
  default:
    Notification.requestPermission((status) => {
      if (status === "granted") notify('Thank you for granting permission');
    });
}