refactor: isolate SSE setup

api/sse/index.js

@@ -0,0 +1,39 @@
+import pg from 'pg';
+
+export function registerSse(app) {
+  const sseClients = [];
+
+  app.get('/events', (req, res) => {
+    res.set({
+      'Content-Type': 'text/event-stream',
+      'Cache-Control': 'no-cache',
+      Connection: 'keep-alive'
+    });
+    res.flushHeaders();
+    res.write(':\n\n');
+    sseClients.push(res);
+
+    res.on('close', () => {
+      const idx = sseClients.indexOf(res);
+      if (idx !== -1) sseClients.splice(idx, 1);
+      res.end();
+    });
+  });
+
+  const broadcast = (data) => {
+    const payload = `data: ${data}\n\n`;
+    sseClients.forEach((client) => client.write(payload));
+  };
+
+  const { Client: PgClient } = pg;
+  const pgClient = new PgClient({ connectionString: process.env.DATABASE_URL });
+  pgClient.connect()
+    .then(() => pgClient.query('LISTEN sse_events'))
+    .then(() => console.log('🛎️  Listening to Postgres channel sse_events'))
+    .catch((err) => console.error('PG listen error', err));
+
+  pgClient.on('notification', (msg) => {
+    console.log('Notificación Postgres:', msg.payload);
+    broadcast(msg.payload);
+  });
+}