diff --git a/src/service-workers/cache.worker.js b/src/service-workers/cache.worker.js
deleted file mode 100644
index 966eb99..0000000
--- a/src/service-workers/cache.worker.js
+++ /dev/null
@@ -1,8 +0,0 @@
-const addResourcesToCache = async (resources) => {
-  const cache = await caches.open('v1');
-  await cache.addAll(resources);
-};
-
-self.addEventListener('install', (event) => {
-  event.waitUntil(addResourcesToCache(['/', '/index.html', '/style.css', '/app.js', '/image-list.js', '/star-wars-logo.jpg', '/gallery/bountyHunters.jpg', '/gallery/myLittleVader.jpg', '/gallery/snowTroopers.jpg']));
-});
diff --git a/src/service-workers/cache.worker.ts b/src/service-workers/cache.worker.ts
new file mode 100644
index 0000000..f3789c5
--- /dev/null
+++ b/src/service-workers/cache.worker.ts
@@ -0,0 +1,22 @@
+declare var self: ServiceWorkerGlobalScope;
+
+const addResourcesToCache = async (resources: string[]): Promise<void> => {
+  const cache = await caches.open('v1');
+  await cache.addAll(resources);
+};
+
+self.addEventListener('install', (event: ExtendableEvent) => {
+  event.waitUntil(
+    addResourcesToCache([
+      '/',
+      '/index.html',
+      '/style.css',
+      '/app.js',
+      '/image-list.js',
+      '/star-wars-logo.jpg',
+      '/gallery/bountyHunters.jpg',
+      '/gallery/myLittleVader.jpg',
+      '/gallery/snowTroopers.jpg'
+    ])
+  );
+});
\ No newline at end of file