TypeError: Cannot redefine property: Request at Function.defineProperty (<anonymous>)

[halilibrahimcelik]

Okay after dealing with TextEncoder and ReadableStream is not defined errors, I finally got chance to test my api but now
I'm getting this error when I run my test on my reservation.test.tsx file.

TypeError: Cannot redefine property: Request
    at Function.defineProperty (<anonymous>)

   9 | import { server } from './__tests__/__mocks__/msw/server';
  10 |
> 11 | beforeAll(() => server.listen());
     |                        ^
  12 | afterEach(() => server.resetHandlers());
  13 | afterAll(() => server.close());
  14 |

  at recordRawFetchHeaders (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/interceptors/ClientRequest/utils/recordRawHeaders.ts:157:10)
  at _ClientRequestInterceptor.setup (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/interceptors/ClientRequest/index.ts:112:5)
  at _ClientRequestInterceptor.apply (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/Interceptor.ts:130:10)
  at BatchInterceptor.setup (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/BatchInterceptor.ts:44:19)
  at BatchInterceptor.apply (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/Interceptor.ts:130:10)
  at SetupServerApi.listen (node_modules/.pnpm/[email protected][email protected]/node_modules/msw/src/node/SetupServerCommonApi.ts:102:22)
  at Object.listen (jest.setup.js:11:24)

https://github.com/halilibrahimcelik/jest-test-repo-base-venue this is the project repo btw, you can look at my configurations on msw handlers and servers file as well as jest files.

Any help really appreciated.

[halilibrahimcelik]

When I look at Discussed in #2271, I thought the problem might related to version, so I changed it from 2.4.8 to 2.4.7 as described but my problem was still there. So after further research, I saw this comment #2271 (comment) and finally 2.4.3 version solved my problem.
I also configured my setupfile like this

  const { TextDecoder, TextEncoder } = require('node:util');
const { ReadableStream } = require('node:stream/web');
Object.defineProperties(globalThis, {
TextDecoder: { value: TextDecoder },
TextEncoder: { value: TextEncoder },
ReadableStream: { value: ReadableStream },
});

const { Blob, File } = require('node:buffer');
const { fetch, Headers, FormData, Request, Response } = require('undici');

Object.defineProperties(globalThis, {
fetch: { value: fetch, writable: true },
 Blob: { value: Blob },
File: { value: File },
Headers: { value: Headers },
FormData: { value: FormData },
 Request: { value: Request },
Response: { value: Response },
});

[Hagendorn]

I ran in the same issue and switched to this setup and removed undici completely:
#1916 (comment)
and with this switch the error is gone

[okusarobert]

When I look at Discussed in #2271, I thought the problem might related to version, so I changed it from 2.4.8 to 2.4.7 as described but my problem was still there. So after further research, I saw this comment #2271 (comment) and finally 2.4.3 version solved my problem. I also configured my setupfile like this

  const { TextDecoder, TextEncoder } = require('node:util');
const { ReadableStream } = require('node:stream/web');
Object.defineProperties(globalThis, {
TextDecoder: { value: TextDecoder },
TextEncoder: { value: TextEncoder },
ReadableStream: { value: ReadableStream },
});

const { Blob, File } = require('node:buffer');
const { fetch, Headers, FormData, Request, Response } = require('undici');

Object.defineProperties(globalThis, {
fetch: { value: fetch, writable: true },
 Blob: { value: Blob },
File: { value: File },
Headers: { value: Headers },
FormData: { value: FormData },
 Request: { value: Request },
Response: { value: Response },
});

this solved my issue. Hopefully this gets fixed in the future versions

[iamlucasgomes]

Okay after dealing with TextEncoder and ReadableStream is not defined errors, I finally got chance to test my api but now I'm getting this error when I run my test on my reservation.test.tsx file.

TypeError: Cannot redefine property: Request
    at Function.defineProperty (<anonymous>)

   9 | import { server } from './__tests__/__mocks__/msw/server';
  10 |
> 11 | beforeAll(() => server.listen());
     |                        ^
  12 | afterEach(() => server.resetHandlers());
  13 | afterAll(() => server.close());
  14 |

  at recordRawFetchHeaders (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/interceptors/ClientRequest/utils/recordRawHeaders.ts:157:10)
  at _ClientRequestInterceptor.setup (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/interceptors/ClientRequest/index.ts:112:5)
  at _ClientRequestInterceptor.apply (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/Interceptor.ts:130:10)
  at BatchInterceptor.setup (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/BatchInterceptor.ts:44:19)
  at BatchInterceptor.apply (node_modules/.pnpm/@[email protected]/node_modules/@mswjs/interceptors/src/Interceptor.ts:130:10)
  at SetupServerApi.listen (node_modules/.pnpm/[email protected][email protected]/node_modules/msw/src/node/SetupServerCommonApi.ts:102:22)
  at Object.listen (jest.setup.js:11:24)

https://github.com/halilibrahimcelik/jest-test-repo-base-venue this is the project repo btw, you can look at my configurations on msw handlers and servers file as well as jest files.

Any help really appreciated.

the error TypeError: Cannot redefine property: Request at Function.defineProperty (<anonymous>)

happens because in your polyfill, you didn't allow Request to be configurable

You can adjust it like this

Object.defineProperties(globalThis, {
fetch: { value: fetch, writable: true },
 Blob: { value: Blob },
File: { value: File },
Headers: { value: Headers },
FormData: { value: FormData },
 Request: { value: Request, configurable: true },
Response: { value: Response, configurable: true },
});

[halilibrahimcelik]

Yes but also there is a version issue, when I lowered to 2.4.3 all my problems were gone away.

[takakikasuga]

[IMHO]

@halilibrahimcelik

I refered this document and it's completely worked at [email protected]

https://mswjs.io/docs/faq/#requestresponsetextencoder-is-not-defined-jest

// jest.polyfills.js
/**
 * @note The block below contains polyfills for Node.js globals
 * required for Jest to function when running JSDOM tests.
 * These HAVE to be require's and HAVE to be in this exact
 * order, since "undici" depends on the "TextEncoder" global API.
 *
 * Consider migrating to a more modern test runner if
 * you don't want to deal with this.
 */
 
const { TextDecoder, TextEncoder } = require('node:util')
 
Object.defineProperties(globalThis, {
  TextDecoder: { value: TextDecoder },
  TextEncoder: { value: TextEncoder },
})
 
const { Blob, File } = require('node:buffer')
const { fetch, Headers, FormData, Request, Response } = require('undici')
 
Object.defineProperties(globalThis, {
  fetch: { value: fetch, writable: true },
  Blob: { value: Blob },
  File: { value: File },
  Headers: { value: Headers },
  FormData: { value: FormData },
  Request: { value: Request, configurable: true },
  Response: { value: Response, configurable: true },
})

[kettanaito]

Please note that the Jest usage instructions have been updated today. You are encouraged to use jest-fixed-jsdom environment instead of doing these manual patches.