diff --git a/components/serviceworker.js b/components/serviceworker.js
index 6bb42e43..f6cb0368 100644
--- a/components/serviceworker.js
+++ b/components/serviceworker.js
@@ -99,7 +99,7 @@ export const ServiceWorkerProvider = ({ children }) => {
     // since (a lot of) browsers don't support the pushsubscriptionchange event,
     // we sync with server manually by checking on every page reload if the push subscription changed.
     // see https://medium.com/@madridserginho/how-to-handle-webpush-api-pushsubscriptionchange-event-in-modern-browsers-6e47840d756f
-    navigator.serviceWorker.controller.postMessage({ action: 'SYNC_SUBSCRIPTION' })
+    navigator?.serviceWorker?.controller?.postMessage?.({ action: 'SYNC_SUBSCRIPTION' })
   }, [])
 
   useEffect(() => {
diff --git a/sw/index.js b/sw/index.js
index 654caeb6..ccd95cf8 100644
--- a/sw/index.js
+++ b/sw/index.js
@@ -7,6 +7,7 @@ import { enable } from 'workbox-navigation-preload'
 import manifest from './precache-manifest.json'
 import ServiceWorkerStorage from 'serviceworker-storage'
 
+// comment out to enable workbox console logs
 self.__WB_DISABLE_DEV_LOGS = true
 
 const storage = new ServiceWorkerStorage('sw:storage', 1)
@@ -15,9 +16,6 @@ const storage = new ServiceWorkerStorage('sw:storage', 1)
 // https://developer.chrome.com/docs/workbox/modules/workbox-navigation-preload/
 enable()
 
-// uncomment to disable workbox console logs
-// self.__WB_DISABLE_DEV_LOGS = true
-
 // ignore precache manifest generated by InjectManifest
 // they statically check for the presence of this variable
 console.log(self.__WB_MANIFEST)