Returning redirect from loader not working in jest (web-fetch used)

[Rafal-Jenczelewski]

Hi,

In my unit test env (Node 18.9.1 and jest 29.0.3) redirect call does not work as intended. After searching for solution, I have learned that I should use @remix-run/web-fetch to polyfill Response, so I did just that:

import { fetch, Request, Response } from "@remix-run/web-fetch";

global.fetch = fetch;
global.Request = Request;
global.Response = Response;

but that did not fix the problem. I have debugged react-router's code and I'm pretty sure I have found the cause.

Function isResponse requires response.body to not be undefined:

function isResponse(value: any): value is Response {
  return (
    value != null &&
    typeof value.status === "number" &&
    typeof value.statusText === "string" &&
    typeof value.headers === "object" &&
    typeof value.body !== "undefined"
  );
}

But that check fails in my setup, even tho web-fetch should be compatible.