Added automatic refresh on mercure events

src/mercure/helpers/index.js

@@ -0,0 +1,25 @@
+import { EventSourcePolyfill as EventSource } from 'event-source-polyfill';
+
+export const bindToMercureTopic = (mercureInfo, topic, onMessage) => () => {
+  const { mercureHubUrl, token, loading, error } = mercureInfo;
+
+  if (loading || error) {
+    return undefined;
+  }
+
+  const hubUrl = new URL(mercureHubUrl);
+
+  hubUrl.searchParams.append('topic', topic);
+  const es = new EventSource(hubUrl, {
+    headers: {
+      Authorization: `Bearer ${token}`,
+    },
+  });
+
+  es.onmessage = ({ data }) => onMessage(JSON.parse(data));
+
+  // TODO Handle errors and get a new token
+  es.onerror = () => {};
+
+  return () => es.close();
+};