Not responding with correct status code

Environment

Name	Version
msw	0.26.2
node	14.15.4
OS	Windows 10

Request handlers

import { setupServer } from 'msw/node'
import { rest } from 'msw'

const handlers = [
  rest.patch("/api/Resources/:id", (req, res, ctx) => {
    if (!req.headers.has("Authorization")) {
      return res(ctx.status(401));
    }

    let element = serverData.findIndex((e) => e.id === req.params.id);

    if (element === -1) {
      // this code block is entered
      return res(ctx.status(404), ctx.text(""));
    } else {
      return res(ctx.status(204), ctx.text(""));
    }
  }),
  rest.get("/api/Resources", (req, res, ctx) => {
    if (!req.headers.has("Authorization")) {
      return res(ctx.status(401));
    }

    return res(
      ctx.status(200),
      ctx.json({
        "@odata/stuff": "string",
        values: serverData,
      })
    );
  }),
];

const server = setupServer(...handlers);

Actual request

fetch(`${baseUrl}/${data.id}`, {
      method: "PATCH",
      headers: authHeaderWithContentType,
      body: JSON.stringify(data),
    }).then(handleResponse);

const handleResponse = (response: Response): Promise<any> => {
  console.log(response.status);
  if (response.ok) {
    if (isJson(response)) {
      return response.json();
    } else {
      return response.text();
    }
  } else {
    console.log(response.statusText);
    const error = new ResponseError(response.statusText);
    error.response = response;
    throw error;
  }
};

Current behavior

It returns 200 as a status code. This changes when I change the status code of the second route. The code block that is supposed to return a 404 status is entered but doesn’t return as it seems. Am I missing something?

Expected behavior

It should return a 404 status code causing the fetch request to throw an error.

[flexwie]

I recreated the error in this repository:

https://github.com/flexwie/msw_error

Running npm test will result in a failed test run. I have uncommented another test, that is using the samen handler succesfully for better readability.

[flexwie]

Hey @kettanaito, we added that handleResponse function to throw an error if the status code is >2xx.

element does exists and is -1 (aka not found in the array), what is what I am describing with my test case:

it("should throw error on unknown id", async () => {
    const { update } = useResourceService(mockState as any);

    const response = async () =>
      await update({
        id: "123-456-78",
        no: "123",
        name: "New Name",
      });

    expect(response).toThrowError();
  });

When I try to return some text along the 404 status, the fetch call receives an undefined body and still a 200 status code.

I will try reproduce this issue in a repository and come back to you! Thanks for you assistance so far!