Handle vapid public get init

src/hub.js

@@ -500,7 +500,10 @@ document.addEventListener("DOMContentLoaded", async () => {
   retPhxChannel
     .join()
     .receive("ok", async data => subscriptions.setVapidPublicKey(data.vapid_public_key))
-    .receive("error", res => console.error(res));
+    .receive("error", res => {
+      subscriptions.setVapidPublicKey(null);
+      console.error(res);
+    });
 
   linkChannel.setSocket(socket);
 });

src/subscriptions.js

@@ -50,6 +50,10 @@ export default class Subscriptions {
     // registration becomes null if failed, non null if registered
     while (this.registration === undefined) await nextTick();
     if (!this.registration || !this.registration.pushManager) return null;
+
+    while (this.vapidPublicKey === undefined) await nextTick();
+    if (this.vapidPublicKey === null) return null;
+
     try {
       const convertedVapidKey = urlBase64ToUint8Array(this.vapidPublicKey);