Initial PWA assistant proof of concept

static/sw.js

@@ -0,0 +1,31 @@
+const CACHE_NAME = "opensquared-assistant-v1";
+const ASSETS = [
+  "/",
+  "/styles.css",
+  "/app.js",
+  "/manifest.webmanifest",
+  "/icons/icon.svg"
+];
+
+self.addEventListener("install", (event) => {
+  event.waitUntil(caches.open(CACHE_NAME).then((cache) => cache.addAll(ASSETS)));
+  self.skipWaiting();
+});
+
+self.addEventListener("activate", (event) => {
+  event.waitUntil(
+    caches.keys().then((keys) =>
+      Promise.all(keys.filter((key) => key !== CACHE_NAME).map((key) => caches.delete(key)))
+    )
+  );
+  self.clients.claim();
+});
+
+self.addEventListener("fetch", (event) => {
+  if (event.request.method !== "GET") return;
+  event.respondWith(
+    caches.match(event.request).then((cached) => {
+      return cached || fetch(event.request);
+    })
+  );
+});