XMLHttpRequest

[KhafraDev]

This would solve...

Similar legacy web-apis (atob and btoa) have been added to the node core, it could be useful for developing cross-platform code.

Also, XMLHttpRequest supports progress events which could be useful since this has been an ongoing discussion in fetch for well over half a decade now (whatwg/fetch#607 & whatwg/fetch#65).

The spec itself hardly receives updates so once a stable version is completed, it shouldn't cause any extra maintenance burden. I'd be willing to fix bugs in the implementation, similar to what I do with fetch 😛.

On npm, packages emulating xmlhttprequest have millions of downloads weekly, so there does seem to be some demand for it.
https://www.npmjs.com/package/xmlhttprequest
https://www.npmjs.com/package/xmlhttprequest-ssl
https://www.npmjs.com/package/xhr2

The implementation should look like...

https://github.com/KhafraDev/undici/tree/xmlhttprequest (not done, a prototype for now)

I have also considered...

By exporting a few things from fetch, this could entirely be done by a third-party module piggy-backing on undici's fetch. Since the logic of xhr is intertwined with fetch, it can't be done as easily with node's http/s modules.

Additional context

Mostly just want to ask for your opinions 😄.