Version

v22.2.0

Platform

Microsoft Windows NT 10.0.22631.0 x64

Subsystem

idk :undici package (dependency used by Next.js)

What steps will reproduce the bug?

Create a new Next.js project using the latest version (as of writing, it's Next.js 13.2.4).
In one of the pages , import the Headers object from undici and try to set headers,
let headers = new Headers();
headers.set('Access-Control-Allow-Credentials', true);
headers.set('Access-Control-Allow-Origin', '*');
headers.set('x-auth-token',' process.env.EXAMPLE.TOKEN');

How often does it reproduce? Is there a required condition?

The issue reproduces consistently when running the above steps with Node.js version 22.2.0.

What is the expected behavior? Why is that the expected behavior?

The expected behavior is for the Headers object to correctly accept and set the provided header key-value pairs without throwing any errors. This is the expected behavior because the Headers object should handle string values for both header keys and values according to the documentation and specifications.

What do you see instead?

TypeError: Could not convert argument of type symbol to string.
at webidl.converters.DOMString (node:internal/deps/undici/undici:1977:15)
at webidl.converters.ByteString (node:internal/deps/undici/undici:1982:35)
at Object.record<ByteString, ByteString> (node:internal/deps/undici/undici:1894:30)
at webidl.converters.HeadersInit (node:internal/deps/undici/undici:3424:67)
at new Headers (node:internal/deps/undici/undici:3278:36)

Additional information

"undici": "5.23.0",

Everything is working fine with the Headers object when using Node.js 20.1.0

Fixed in #53034