improved service worker

package.json

@@ -11,6 +11,7 @@
   "license": "ISC",
   "dependencies": {
     "express": "^4.16.3",
+    "fs-extra": "^7.0.0",
     "globby": "^8.0.1"
   }
 }

server.js

@@ -5,6 +5,8 @@ const router = express.Router();
 
 const globby = require("globby");
 
+const fs = require("fs-extra");
+
 router.use(express.static(__dirname + "/static"));
 
 router.get("/js/preloadDependencies.js", async (req, res) => {
@@ -24,6 +26,11 @@ router.get("/js/preloadDependencies.js", async (req, res) => {
 	res.set("Content-Type", "text/javascript").send(js);
 })
 
+router.get("/sw.js", async (req, res) => {
+	let fileName = process.env.NODE_ENV === "production" ? "sw-prod.js" : "sw-dev.js";
+	res.set("Content-Type", "text/javascript").send(await fs.readFile(__dirname + "/static/" + fileName));
+})
+
 if(require.main === module) {
 	server.use(router);
 	server.listen(process.env.PORT || 35452);

static/sw-dev.js

@@ -0,0 +1,2 @@
+
+// sw-dev.js

static/sw-prod.js

@@ -0,0 +1,38 @@
+
+// sw-prod.js
+
+let cacheName = "RCSv2";
+
+self.addEventListener("install", event => {
+	console.log("RubiksCubeSimulator ServiceWorker installing");
+	event.waitUntil((async () => {
+		let cache = await caches.open(cacheName);
+
+		console.log("Opened cache", cacheName)
+
+		await cache.addAll([]);
+
+		console.log("Finished adding to cache")
+
+		return true;
+	})());
+});
+
+self.addEventListener("activate", event => {
+	console.log("RubiksCubeSimulator ServiceWorker activated");
+})
+
+self.addEventListener("fetch", event => {
+	if(event.request.method !== "GET") return;
+
+	event.respondWith((async () => {
+
+		const cache = await caches.open(cacheName);
+		const cachedResponse = await cache.match(event.request);
+
+		event.waitUntil(cache.add(await event.request.clone()));
+
+		return cachedResponse || fetch(event.request);
+
+	})());
+});