Add live reload on changes

server/src/live-reload.ts

@@ -0,0 +1,45 @@
+import type http from 'node:http';
+import { WebSocketServer, type WebSocket } from 'ws';
+import { logger } from './logger.js';
+
+let wss: WebSocketServer | null = null;
+
+export function initLiveReload(server: http.Server): void {
+  if (wss) return;
+
+  const enabled = process.env.LIVE_RELOAD_WS_ENABLED === 'true';
+  if (!enabled) {
+    logger.info({ event: 'live_reload.disabled' }, 'Live reload websocket disabled');
+    return;
+  }
+
+  const wsPath = process.env.LIVE_RELOAD_WS_PATH || '/__live_reload';
+
+  wss = new WebSocketServer({ server, path: wsPath });
+  wss.on('connection', (socket: WebSocket) => {
+    logger.info({ event: 'live_reload.connected' }, 'Live reload client connected');
+    socket.on('close', () => {
+      logger.info({ event: 'live_reload.disconnected' }, 'Live reload client disconnected');
+    });
+  });
+
+  logger.info({ event: 'live_reload.started', path: wsPath }, 'Live reload websocket started');
+}
+
+export function broadcastReload(reason: string, data?: Record<string, unknown>): void {
+  if (!wss) return;
+
+  const payload = JSON.stringify({
+    type: 'reload',
+    ts: Date.now(),
+    reason,
+    ...data,
+  });
+
+  for (const client of wss.clients) {
+    if (client.readyState === client.OPEN) {
+      client.send(payload);
+    }
+  }
+}
+