caching only while fetching new records (#39)

Co-authored-by: Gokul K <[email protected]>

Author: gokulk16

sw.js

@@ -1,30 +1,50 @@
 // sw.js
 const CACHE_NAME = "ttc-cache-v1";
-const urlsToCache = [
-  "/",
-  "/index.html",
-  "/css/*.css",
-  "/js/editor.js",
-  "/favicon-150.png",
-  "/favicon-48.png",
-  "/favicon-512.png",
-  "/favicon-192.png",
-];
 
-// Install the service worker
-self.addEventListener("install", (event) => {
-  event.waitUntil(
-    caches.open(CACHE_NAME).then((cache) => {
-      return cache.addAll(urlsToCache);
+// Fetch event: Cache responses immediately after fetching
+self.addEventListener("fetch", (event) => {
+  event.respondWith(
+    caches.match(event.request).then((cachedResponse) => {
+      // If a match is found in the cache, return it; otherwise, fetch from network
+      return (
+        cachedResponse ||
+        fetch(event.request).then((networkResponse) => {
+          // Check if we received a valid response
+          if (
+            !networkResponse ||
+            networkResponse.status !== 200 ||
+            networkResponse.type !== "basic"
+          ) {
+            return networkResponse; // Return the response if it's not valid for caching
+          }
+
+          // Clone the response because we can only use it once
+          const responseToCache = networkResponse.clone();
+
+          // Open the cache and store the response
+          caches.open(CACHE_NAME).then((cache) => {
+            cache.put(event.request, responseToCache);
+          });
+
+          return networkResponse; // Return the original network response
+        })
+      );
     })
   );
 });
 
-// Fetch the cached assets
-self.addEventListener("fetch", (event) => {
-  event.respondWith(
-    caches.match(event.request).then((response) => {
-      return response || fetch(event.request);
+// Activate event: Clean up old caches if necessary
+self.addEventListener("activate", (event) => {
+  const cacheWhitelist = [CACHE_NAME];
+  event.waitUntil(
+    caches.keys().then((cacheNames) => {
+      return Promise.all(
+        cacheNames.map((cacheName) => {
+          if (cacheWhitelist.indexOf(cacheName) === -1) {
+            return caches.delete(cacheName);
+          }
+        })
+      );
     })
   );
-});
+});