Bundle error - nodejs EventSource

Hello guys,

I’m encountering an issue while trying to use the “eventsource” module in Node.js to perform a test using Server-Sent Events (SSE). I’m following the step-by-step guide from k6 modules to create a bundle. The bundle is being created successfully, but when I run the code, I receive the following

error: [0025] TypeError: Cannot read property 'protocol' of undefined

I’m not sure if the error lies in my code or if I’m doing something wrong in the process.

My code:

import EventSource from 'eventsource';
import { check, sleep } from 'k6';

export let options = {
  stages: [
    { duration: '30s', target: 1 },
    { duration: '30s', target: 1 },
    { duration: '30s', target: 0 },

export default function () {
  const url = "x";

  const es = new EventSource(url);

  let event;

  const processEvent = e => {
    event = e;

  es.addEventListener("open", processEvent);
  es.addEventListener("error", processEvent);


  check(event, { 'is a valid event': (e) => e.type == "open" });

the output:

TypeError: Cannot read property 'protocol' of undefined
running at file:///Users/rafael.nascimentoo/Documents/clones/testebundle/example-project/dist/login.bundle.js:2:113336(22)
        at call (native)
        at file:///Users/rafael.nascimentoo/Documents/clones/testebundle/example-project/dist/login.bundle.js:2:50978(12)
        at O (file:///Users/rafael.nascimentoo/Documents/clones/testebundle/example-project/dist/login.bundle.js:2:36222(195))
        at h (file:///Users/rafael.nascimentoo/Documents/clones/testebundle/example-project/dist/login.bundle.js:2:38211(88))
        at u (file:///Users/rafael.nascimentoo/Documents/clones/testebundle/example-project/dist/login.bundle.js:2:150251(14))
        at native  executor=ramping-vus scenario=default source=stacktrace
running (0m01.6s), 0/1 VUs, 1778 complete and 1 interrupted iterations
default ✗ [--------------------------------------] 0/1 VUs  0m01.6s/1m30.0s

     data_received........: 0 B  0 B/s
     data_sent............: 0 B  0 B/s
     iteration_duration...: avg=527.51µs min=160.55µs med=317.13µs max=28.16ms p(90)=722.15µs p(95)=1.17ms
     iterations...........: 1779 1084.441345/s
     vus..................: 1    min=1         max=1
     vus_max..............: 1    min=1         max=1

I would appreciate any insights or suggestions to help resolve this issue. Thank you in advance for your assistance!