wsclock_front/src/AlarmNotif.js

/* Small set of function for Notification handling */

/* Stores Notifications instance associated with alarm name */
var _notifications = {};
var _requested = false;

/* Return True if the browser supports Notifications
 * Note : Return False in case user denied the permission to notify
 */
function support() {
	return "Notification" in window && Notification.permission !== 'denied'
}

/* Return True if Notifications are supported and permission granted */
function granted() {
	if(!support()) {
		return false;
	}
	return Notification.permission === 'granted'
}

/* Request permission for notifications */
function requestPermission() {
	if(_requested) { return; }
	_requested = true
	Notification.requestPermission()
}

/* Given an alarm name and a ringtime, create a new notification
 * for the ringing alarm if none existing
 */
function set_notif_alrm(name:string, time_str:string) {
	if(!support()) { return; }
	if(!granted()) {
		if(_requested) { return; } // allready requested
		_requested = true
		Notification.requestPermission().then(function (perm) {
			set_notif_alrm(name)
		})
	}
	if(name in _notifications) { return; }

	let notif = new Notification(time_str+" '"+name+"'",
				{body:time_str+' alarm "'+name+'" is ringing.'})
	
	notif.addEventListener('close', () => {
		if(!name in _notifications) {
			delete _notifications[name];
		}
	});

	notif.addEventListener('error', () => {
		if(!name in _notifications) {
			delete _notifications[name];
		}
	});

	_notifications[name] = notif;
}

/* Given an alarm name, delete & close associated Notification if one exists */
function unset_notif_alrm(name:string) {
	if(!support()) { return; }
	if(name in _notifications) {
		_notifications[name].close()
		delete _notifications[name]
	}
}

const Notif = {

	set: set_notif_alrm,
	unset: unset_notif_alrm,
	requestPermission: requestPermission,

};

export default Notif;