skip waiting for serviceworker if found to be waiting

app.js

@@ -70,6 +70,9 @@ class Setup {
           '/sw.js',
           {scope: '/'}
         )
+      if (registration.waiting) {
+        registration.active.postMessage(['skipWaiting'])
+      }
     } catch (err) {
       console.error(
         'error registering service worker', err

sw.js

@@ -61,4 +61,10 @@ self.addEventListener('fetch', event => {
 
 self.addEventListener('activate', event => {
   event.waitUntil(clients.claim())
+})
+
+self.addEventListener('message', e => {
+  if (Array.isArray(e.data) && e.data[0] === 'skipWaiting') {
+    self.skipWaiting()
+  }
 })