Extract shlink-web-component outside of src folder

shlink-web-component/mercure/helpers/index.ts

@@ -0,0 +1,31 @@
+import { EventSourcePolyfill as EventSource } from 'event-source-polyfill';
+import type { MercureInfo } from '../reducers/mercureInfo';
+
+export const bindToMercureTopic = <T>(mercureInfo: MercureInfo, topics: string[], onMessage: (message: T) => void, onTokenExpired: () => void) => { // eslint-disable-line max-len
+  const { mercureHubUrl, token, loading, error } = mercureInfo;
+
+  if (loading || error || !mercureHubUrl) {
+    return undefined;
+  }
+
+  const onEventSourceMessage = ({ data }: { data: string }) => onMessage(JSON.parse(data) as T);
+  const onEventSourceError = ({ status }: { status: number }) => status === 401 && onTokenExpired();
+
+  const subscriptions = topics.map((topic) => {
+    const hubUrl = new URL(mercureHubUrl);
+
+    hubUrl.searchParams.append('topic', topic);
+    const es = new EventSource(hubUrl, {
+      headers: {
+        Authorization: `Bearer ${token}`,
+      },
+    });
+
+    es.onmessage = onEventSourceMessage;
+    es.onerror = onEventSourceError;
+
+    return es;
+  });
+
+  return () => subscriptions.forEach((es) => es.close());
+};