adding status-update messages (isOnline, isLoggedIn)

Author: getify

web/js/blog.js

@@ -27,10 +27,12 @@
 		window.addEventListener("online",function online(){
 			offlineIcon.classList.add("hidden");
 			isOnline = true;
+			sendStatusUpdate();
 		},false);
 		window.addEventListener("offline",function offline(){
 			offlineIcon.classList.remove("hidden");
 			isOnline = false;
+			sendStatusUpdate();
 		},false);
 	}
 
@@ -40,11 +42,39 @@
 		});
 
 		svcworker = swRegistration.installing || swRegistration.waiting || swRegistration.active;
+		sendStatusUpdate(svcworker);
 
 		// listen for new service worker to take over
 		navigator.serviceWorker.addEventListener("controllerchange",async function onController(){
 			svcworker = navigator.serviceWorker.controller;
+			sendStatusUpdate(svcworker);
 		});
+
+		navigator.serviceWorker.addEventListener("message",onSWMessage,false);
+	}
+
+	function onSWMessage(evt) {
+		var { data } = evt;
+		if (data.statusUpdateRequest) {
+			console.log("Status update requested from service worker, responding...");
+			sendStatusUpdate(evt.ports && evt.ports[0]);
+		}
+	}
+
+	function sendStatusUpdate(target) {
+		sendSWMessage({ statusUpdate: { isOnline, isLoggedIn } },target);
+	}
+
+	function sendSWMessage(msg,target) {
+		if (target) {
+			target.postMessage(msg);
+		}
+		else if (svcworker) {
+			svcworker.postMessage(msg);
+		}
+		else if (navigator.serviceWorker.controller) {
+			navigator.serviceWorker.controller.postMessage(msg);
+		}
 	}
 
 })();

web/js/sw.js

@@ -1,17 +1,20 @@
 "use strict";
 
-var version = 1;
+var version = 2;
+var isOnline = true;
+var isLoggedIn = false;
 
 self.addEventListener("install",onInstall);
 self.addEventListener("activate",onActivate);
+self.addEventListener("message",onMessage);
 
 main().catch(console.error);
 
 
 // ****************************
 
 async function main() {
-	console.log(`Service Worker (v${version}) started`);
+	await sendMessage({ statusUpdateRequest: true });
 }
 
 function onInstall(evt) {
@@ -27,3 +30,21 @@ async function handleActivation() {
 	await clients.claim();
 	console.log(`Service Worker (v${version}) activated`);
 }
+
+async function sendMessage(msg) {
+	var allClients = await clients.matchAll({ includeUncontrolled: true, });
+	return Promise.all(
+		allClients.map(function sendTo(client){
+			var chan = new MessageChannel();
+			chan.port1.onmessage = onMessage;
+			return client.postMessage(msg,[chan.port2]);
+		})
+	);
+}
+
+function onMessage({ data }) {
+	if ("statusUpdate" in data) {
+		({ isOnline, isLoggedIn } = data.statusUpdate);
+		console.log(`Service Worker (v${version}) status update... isOnline:${isOnline}, isLoggedIn:${isLoggedIn}`);
+	}
+}