db/events: don't return `author` unless it exists

src/db/events.ts

@@ -200,26 +200,31 @@ async function getFilters<K extends number>(
     query = query.limit(opts.limit);
   }
 
-  return (await query.execute()).map((row) => ({
+  return (await query.execute()).map((row) => {
+    const event: DittoEvent<K> = {
       id: row.id,
-    kind: row.kind,
+      kind: row.kind as K,
       pubkey: row.pubkey,
       content: row.content,
       created_at: row.created_at,
       tags: JSON.parse(row.tags),
-    author: row.author_id
-      ? {
+      sig: row.sig,
+    };
+
+    if (row.author_id) {
+      event.author = {
         id: row.author_id,
-        kind: row.author_kind!,
+        kind: row.author_kind! as 0,
         pubkey: row.author_pubkey!,
         content: row.author_content!,
         created_at: row.author_created_at!,
         tags: JSON.parse(row.author_tags!),
         sig: row.author_sig!,
+      };
     }
-      : undefined,
-    sig: row.sig,
-  } as DittoEvent<K>));
+
+    return event;
+  });
 }
 
 /** Delete events based on filters from the database. */