Update sw.js

sw.js

@@ -11,8 +11,8 @@ const assetsToCache = [
 
 self.addEventListener('install', event => {
     event.waitUntil(
-        caches.open(cacheName).then(cache => {
-            cache.addAll(assets);
+        caches.open(CACHE_NAME).then(cache => {
+            cache.addAll(assetsToCache);
         })
     );
 });
@@ -34,4 +34,4 @@ self.addEventListener('activate', event => {
             );
         })
     );
-});
+});