npm-websocket-demo.js

const WebSocketServer = require('websocket').server
const WebSocketClient = require('websocket').client
const http = require('http')

const command = process.argv[2]

if (command === undefined) {
    console.log('Please provide a command: server or client')
    process.exit(1)
}

if (command === 'server') {
    serverCmd()
} else if (command === 'client') {
    clientCmd()
} else {
    console.error(`${command} not found`)
    process.exit(1)
}

function serverCmd() {
    const server = http.createServer((_, res) => {
        res.writeHead(404)
        res.end()
    })
    server.listen(8080, () => {
        console.log('Listening on port 8080')
    })
    const wsServer = new WebSocketServer({ httpServer: server })
    wsServer.on('request', request => {
        const client = request.accept()
        client.on('message', message => {
            console.log('Received message:', message.utf8Data)
            client.sendUTF('Hello, world!')
        })
        client.on('close', () => {
            console.log('Connection closed')
        })
    })
}


function clientCmd() {
    const client = new WebSocketClient()
    client.on('connectFailed', err => {
        console.error('Connect error:', err)
    })
    client.on('connect', connection => {
        console.log('Connected')
        connection.on('error', err => {
            console.error('Connection error:', err)
        })
        connection.on('close', () => {
            console.log('Connection closed')
        })
        connection.on('message', message => {
            console.log('Received message:', message.utf8Data)
        })
        connection.sendUTF('Hello, world!')
    })
    client.connect('ws://localhost:8080')
}

Thanks! I will workaround this.