feat: timeline fragments

packages/system-react/src/useReactions.ts

@@ -0,0 +1,34 @@
+import { useMemo } from "react";
+import { RequestBuilder, EventKind, NoteCollection, NostrLink } from "@snort/system";
+import { useRequestBuilder } from "./useRequestBuilder";
+
+export function useReactions(
+  subId: string,
+  ids: Array<NostrLink>,
+  others?: (rb: RequestBuilder) => void,
+  leaveOpen?: boolean,
+) {
+  const sub = useMemo(() => {
+    const rb = new RequestBuilder(subId);
+    rb.withOptions({ leaveOpen });
+
+    if (ids.length > 0) {
+      const grouped = ids.reduce(
+        (acc, v) => {
+          acc[v.type] ??= [];
+          acc[v.type].push(v);
+          return acc;
+        },
+        {} as Record<string, Array<NostrLink>>,
+      );
+
+      for (const [, v] of Object.entries(grouped)) {
+        rb.withFilter().kinds([EventKind.Reaction, EventKind.Repost, EventKind.ZapReceipt]).replyToLink(v);
+      }
+    }
+    others?.(rb);
+    return rb.numFilters > 0 ? rb : null;
+  }, [ids]);
+
+  return useRequestBuilder(NoteCollection, sub);
+}