added useChannelMetadata and support kind 41

src/utils/hooks/useChannelMetadata.tsx

@@ -0,0 +1,52 @@
+import { RelayContext } from '@components/relaysProvider';
+
+import { updateChannelMetadata } from '@utils/storage';
+
+import { useCallback, useContext, useEffect, useRef, useState } from 'react';
+
+export const useChannelMetadata = (id: string, fallback: string) => {
+  const [pool, relays]: any = useContext(RelayContext);
+  const [metadata, setMetadata] = useState(null);
+  const unsubscribe = useRef(null);
+
+  const fetchMetadata = useCallback(() => {
+    unsubscribe.current = pool.subscribe(
+      [
+        {
+          kinds: [41],
+          '#e': [id],
+        },
+      ],
+      relays,
+      (event: { content: string }) => {
+        const json = JSON.parse(event.content);
+        // update state
+        setMetadata(json);
+        // update metadata in database
+        updateChannelMetadata(id, event.content);
+      },
+      undefined,
+      undefined,
+      {
+        unsubscribeOnEose: true,
+        logAllEvents: false,
+      }
+    );
+  }, []);
+
+  useEffect(() => {
+    const json = JSON.parse(fallback);
+    setMetadata(json);
+
+    // fetch kind 41
+    fetchMetadata();
+
+    return () => {
+      if (unsubscribe.current) {
+        unsubscribe.current();
+      }
+    };
+  }, [fetchMetadata]);
+
+  return metadata;
+};