Hacktoberfest 2026: the issues maintainers tagged for October, open and beginner-friendly. Browse Hacktoberfest issues

Failed to execute 'postMessage' on 'DedicatedWorkerGlobalScope': function transformRequest(data, headers) { normalizeHeaderName(headers, 'Accept'); normalizeHeaderName(...<omitted>... } could not be cloned.

Open
#121 1 comment 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
javascript, webpack
Domain
tooling, web-dev

Research direction

Start with the worker.js and app.js examples, then inspect the workerize-loader!./worker entry point and its message-passing path. Reproduce expensive() with the shown axios request and trace the returned value through postMessage; done means the worker call no longer produces the reported structured-clone error.

Written by the indexing model from the issue text.

Description

I query a large Firebase collection in my app.
I'd like to use axios in my app. But it is wrong

`
// worker.js

import axios from "axios";
import 'regenerator-runtime';

export async function expensive() {
const res = await axios.get('https://vdata.amap.com/tiles?mapType=normal&v=3&style=5&key=f97efc35164149d0c0f299e7a8adb3d2&version=1.4.17&rd=2&flds=roadlabel,poilabel&t=9,432,204;9,436,204;9,432,201;9,436,201;9,432,203;9,436,203;9,433,204;9,435,204;9,432,202;9,436,202&lv=9&key=f97efc35164149d0c0f299e7a8adb3d2&preload=0');
console.log(res)
return res;
}
`
When I run the worker as follows:

// app.js
import Worker from 'workerize-loader!./worker';

`
let instance = worker()

instance.expensive().then(data => {
  console.log(`${data}`)
})

`

Failed to execute 'postMessage' on 'DedicatedWorkerGlobalScope': function transformRequest(data, headers) { normalizeHeaderName(headers, 'Accept'); normalizeHeaderName(...... } could not be cloned.

Is it a bug in workerize or is it me doing something wrong?

Dominant language
JavaScript
Stars
2.3k
Forks
85
PR merge metrics
No merged PRs in 30d

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from developit/workerize-loader

All issues in developit/workerize-loader

Similar issues

More JavaScript issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.