Add nonblocking/asyn I/O operations

backend/routes/notes.routes.js

@@ -1,25 +1,38 @@
 import { Router } from 'express';
-import { getAllNotes } from '../db/notes.dao.js';
+import { pipeline } from 'node:stream/promises';
+import { getAllNotes, streamAllNotes } from '../db/notes.dao.js';
 import { clusterNotes } from '../services/clustering.service.js';
+import { jsonArray } from '../lib/streams.js';
 
 const router = Router();
 
 router.get('/', async (req, res) => {
   try {
-    const notes = await getAllNotes();
-    res.json(notes);
+    const rows = await streamAllNotes();
+    res.type('application/json');
+    await pipeline(rows, jsonArray(), res);
   } catch (err) {
     console.error(`Error loading notes: ${err}`);
+    if (res.headersSent) {
+      res.destroy(err);
+      return;
+    }
     res.status(500).json({ error: 'Failed to load notes' });
   }
 });
 
 router.post('/cluster', async (req, res) => {
+  const controller = new AbortController();
+  res.on('close', () => {
+    if (!res.writableEnded) controller.abort();
+  });
+
   try {
     const notes = await getAllNotes();
-    const result = await clusterNotes(notes);
+    const result = await clusterNotes(notes, { signal: controller.signal });
     res.json(result);
   } catch (err) {
+    if (controller.signal.aborted) return;
     console.error(`Clustering failed: ${err}`);
     res.status(500).json({ error: 'Clustering failed' });
   }