fix: use message.content -- limitation from stompjs

Author: fortin-mo

src/socket-sockjs.js

@@ -66,7 +66,7 @@ export default function (socketUrl, customData, _path, options) {
       socketProxy.emit('connect');
     } else if (message.type === 'LEAVE') {
       socket.close();
-      socketProxy.emit('disconnect', message.reason || 'server left');
+      socketProxy.emit('disconnect', message.content || 'server left');
     } else if (message.type === 'SESSION_CONFIRM') {
       socketProxy.emit('session_confirm', socketProxy.id);
     } else if (message.type === 'CHAT') {