websocket.js

import ws from "k6/ws";
import { check } from "k6";

export default function () {
    var url = "ws://echo.websocket.org";
    var params = { "tags": { "my_tag": "hello" } };

    var response = ws.connect(url, params, function (socket) {
        socket.on('open', function open() {
            console.log('connected');
            socket.send(Date.now());

            socket.setInterval(function timeout() {
                socket.ping();
                console.log("Pinging every 1sec (setInterval test)");
            }, 1000);
        });

        socket.on('ping', function () {
            console.log("PING!");
        });

        socket.on('pong', function () {
            console.log("PONG!");
        });

        socket.on('pong', function () {
            // Multiple event handlers on the same event
            console.log("OTHER PONG!");
        });

        socket.on('message', function incoming(data) {
            console.log(`Roundtrip time: ${Date.now() - data} ms`);
            socket.setTimeout(function timeout() {
                socket.send(Date.now());
            }, 500);
        });

        socket.on('close', function close() {
            console.log('disconnected');
        });

        socket.on('error', function (e) {
            if (e.error() != "websocket: close sent") {
                console.log('An unexpected error occured: ', e.error());
            }
        });

        socket.setTimeout(function () {
            console.log('2 seconds passed, closing the socket');
            socket.close();
        }, 2000);
    });

    check(response, { "status is 101": (r) => r && r.status === 101 });
};