diff --git a/src/components/frame/XImgWorker.ts b/src/components/frame/XImgWorker.ts
index ed2db2d8..6b5d3f33 100644
--- a/src/components/frame/XImgWorker.ts
+++ b/src/components/frame/XImgWorker.ts
@@ -1,6 +1,8 @@
 import { CacheExpiration } from 'workbox-expiration';
 import { workerExport } from '../../worker';
 
+declare var self: ServiceWorkerGlobalScope;
+
 interface BlobCallback {
   resolve: (blob: Blob) => void;
   reject: (err: Error) => void;
diff --git a/src/service-worker.js b/src/service-worker.ts
similarity index 97%
rename from src/service-worker.js
rename to src/service-worker.ts
index f3bcfad5..bfafb885 100644
--- a/src/service-worker.js
+++ b/src/service-worker.ts
@@ -3,6 +3,8 @@ import { NetworkFirst, CacheFirst } from 'workbox-strategies';
 import { registerRoute } from 'workbox-routing';
 import { ExpirationPlugin } from 'workbox-expiration';
 
+declare var self: ServiceWorkerGlobalScope;
+
 precacheAndRoute(self.__WB_MANIFEST);
 cleanupOutdatedCaches();
 
diff --git a/tsconfig.json b/tsconfig.json
index ea8055d2..5fd8843c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,6 +2,7 @@
   "compilerOptions": {
     "lib": [
       "dom",
+      "WebWorker",
       "es2017"
     ],
     "target": "ES2017",
diff --git a/webpack.config.ts b/webpack.config.ts
index 0462c561..42c91fc2 100644
--- a/webpack.config.ts
+++ b/webpack.config.ts
@@ -109,7 +109,7 @@ module.exports = {
 
     // Bundle service worker
     new WorkboxPlugin.InjectManifest({
-      swSrc: path.resolve(path.join('src', 'service-worker.js')),
+      swSrc: path.resolve(path.join('src', 'service-worker.ts')),
       swDest: 'memories-service-worker.js',
       maximumFileSizeToCacheInBytes: (isDev ? 10 : 4) * 1024 * 1024,
     }),