diff --git a/app/assets/javascripts/service-worker.js.erb b/app/assets/javascripts/service-worker.js.erb
index 959ed9a7160..fba1cfdef2d 100644
--- a/app/assets/javascripts/service-worker.js.erb
+++ b/app/assets/javascripts/service-worker.js.erb
@@ -165,7 +165,7 @@ self.addEventListener('notificationclick', function(event) {
   );
 });
 
-self.addEventListener('message', event => {
+self.addEventListener('message', function(event) {
   if('lastAction' in event.data){
     lastAction = event.data.lastAction;
   }});