.........../node_modules/socket.io/lib/transports/websocket.js:168
    var length = Buffer.byteLength(data)
                        ^
TypeError: Argument must be a string
    at WebSocket.write (.........../node_modules/socket.io/lib/transports/websocket.js:168:25)
    at WebSocket.flush (.........../node_modules/socket.io/lib/transports/websocket.js:197:10)
    at Socket.<anonymous> (.........../node_modules/socket.io/lib/transports/websocket.js:143:14)
    at Socket.emit (events.js:64:17)
    at Socket._onReadable (net.js:673:31)
    at IOWatcher.onReadable [as callback] (net.js:177:10)