Cannot read properties of undefined ( ws + nodejs ) about unit HOT 4 OPEN

server = require('http').createServer(function() {});
webSocketServer = require('websocket').server;

server.listen(3010, function() {});

var wsServer = new webSocketServer({
    maxReceivedMessageSize: 0x1000000000,
    maxReceivedFrameSize: 0x1000000000,
    fragmentOutgoingMessages: false,
    fragmentationThreshold: 0x1000000000,
    httpServer: server,
})

var clients = [];


wsServer.on('request', request => {
    var connection = request.accept(null);
    console.log('New client connected!');

    clients.push(connection);

    connection.send('connection established');
    connection.on('message', data => {
        clients.forEach(client => {
            console.log(`distributing message: ${data}`)

            if (data.type === 'utf8') {
                client.send(data.utf8Data);
            } else if (data.type === 'binary') {
                client.send(data.binaryData);
            }

        })
    })
    connection.onerror = function () {
        console.log('websocket error')
    }

    connection.on('close', () => console.log('Client has disconnected!'));
})