self.addEventListener('push', function(event) {
    var apiPath = 'https://kprucontrol.kpru.ac.th/notification.php';
    event.waitUntil(registration.pushManager.getSubscription().then(function(subscription) {

        return fetch(apiPath).then(function(response) {
            if (response.status !== 200) {
                throw new Error();
            }

            return response.json().then(function(data) {
                var title = data.title;
                // var message = data.body;
                // var icon = data.icon;
                // var tag = data.tag;
                // var url = data.url;
                return self.registration.showNotification(title, {
                    // body: message,
                    // icon: icon,
                    // tag: tag,
                    // data: url
                });
            })
        }).catch(function(err) {

        })

    }));
    return;
});