wpn/static/S3_sw.js

// (A) INSTANT WORKER ACTIVATION
self.addEventListener("install", evt => self.skipWaiting());

// (B) CLAIM CONTROL INSTANTLY
self.addEventListener("activate", evt => self.clients.claim());

// (C) LISTEN TO PUSH
self.addEventListener("push", evt => {
  const data = evt.data.json();
  console.log("got: " + evt.data);
  self.registration.showNotification(data.title, {
    body: data.body,
    icon: data.icon,
    image: data.image
  });
});

// (D) HANDLE USER INTERACTION
// https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerGlobalScope/notificationclick_event
self.addEventListener( "notificationclick", (event) => {
    event.notification.close();
    if (event.action === "archive") {
      // User selected the Archive action.
      //archiveEmail();
    } else {
      // User selected (e.g., clicked in) the main body of notification.
      //clients.openWindow("/inbox");
    }
  },
  false,
);