1 files changed, 51 insertions, 0 deletions
diff --git a/src/worker/sw.ts b/src/worker/sw.ts
new file mode 100644
index 0000000..e125879
--- /dev/null
+++ b/src/worker/sw.ts
@@ -0,0 +1,51 @@
+declare var self: ServiceWorkerGlobalScope;
+export {};
+
+
+const sw_cache = {
+	offline: "/offline",
+	default: [
+		"/index.js",
+		"/index.css",
+		"/app.webmanifest",
+		"/favicon.svg"
+	],
+	store: "app",
+}
+
+async function install() {
+	const cache = await self.caches.open(sw_cache.store)
+	return cache.addAll([sw_cache.offline, ...sw_cache.default])
+}
+
+async function activate() {
+	const keys = await self.caches.keys()
+	return Promise.all(keys.map(key => {
+		return key !== sw_cache.store ? self.caches.delete(key) : undefined
+	}))
+}
+
+async function req(event: FetchEvent) {
+	const cache = await caches.open(sw_cache.store)
+	const cachedResponse = await cache.match(event.request)
+	var networkResponse
+	try {
+		networkResponse = await fetch(event.request)
+		if (networkResponse.ok) {
+			cache.put(event.request, networkResponse.clone())
+		}
+	} catch(error) {
+		console.error(error)
+		if (event.request.mode === "navigate") {
+			networkResponse = await caches.match("/offline")
+		}
+	}
+	return (cachedResponse || networkResponse) as Response
+
+}
+
+self.addEventListener("install", event => event.waitUntil(install()))
+
+self.addEventListener("activate", event => event.waitUntil(activate()))
+
+self.addEventListener("fetch", event => event.respondWith(req(event)))