[feat] Add category filtering

pages/api/getTopicList.ts

 function getTopicsInDatabase(notionResp: any): Topic[] {
   return notionResp.results.map((block: any) => ({
     blockId: block.id,
-    name: block.properties.Name.title[0].plain_text,
+    name: block.properties.Name?.title?.[0]?.plain_text ?? "Untitled",
   }));
 }
 
   });
 
   const {
-    query: { type },
+    query: { type, category },
   } = req;
   const blockId = getDatabaseId(type as DatabaseType);
   if (!blockId) {
     res.status(404).json({ status: "Not found." });
   } else {
+    const categoryFilter = category
+      ? {
+          filter: {
+            property: "Category",
+            select: {
+              equals: category,
+            },
+          },
+        }
+      : {};
     const resp = await notion.databases.query({
       database_id: blockId,
       sorts: [
           direction: "ascending",
         },
       ],
+      ...categoryFilter,
     });
+    console.log(resp);
     res.status(200).json(getTopicsInDatabase(resp));
   }
 }