miniflare: The requested module 'ws' does not provide an export named 'WebSocketServer'

custom-test-env.mjs

import NodeEnvironment from 'jest-environment-node'

export default class CustomTestEnvironment extends NodeEnvironment {
  async setup() {
    await super.setup()
    ;['atob', 'btoa', 'AbortSignal'].forEach((fn) => {
      if (typeof this.global[fn] === 'undefined') {
        this.global[fn] = global[fn]
      }
    })
  }
}

index.test.ts

import { Miniflare } from 'miniflare'

test('miniflare', async () => {
  const mf = new Miniflare({
    script: `export default {
      async fetch() {
        return new Response('Ok')
      }
    }`,
    modules: true,
  })

  const res = await mf.dispatchFetch('file:')

  expect(await res.text()).toBe('Ok')
})

jest.config.js

/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
const config = {
  testEnvironment: '<rootDir>/custom-test-env.mjs',
  verbose: true,
  preset: 'ts-jest/presets/default-esm',
  globals: { 'ts-jest': { useESM: true } },
  transform: {},
  moduleNameMapper: {
    '^(\\.{1,2}/.*)\\.js$': '$1',
  },
}

export default config

package.json

{
  "name": "tmp",
  "version": "1.0.0",
  "type": "module",
  "license": "MIT",
  "scripts": {
    "test": "NODE_OPTIONS=--experimental-vm-modules jest",
    "postinstall": "patch-package"
  },
  "devDependencies": {
    "jest": "27.3.1",
    "jest-environment-node": "27.3.1",
    "miniflare": "2.0.0-next.2",
    "patch-package": "6.4.7",
    "ts-jest": "27.0.7"
  }
}

patches-@miniflare+http-server+2.0.0-next.2.patch

diff --git a/node_modules/@miniflare/http-server/dist/src/index.js b/node_modules/@miniflare/http-server/dist/src/index.js
index 69f51d0..e852c31 100644
--- a/node_modules/@miniflare/http-server/dist/src/index.js
+++ b/node_modules/@miniflare/http-server/dist/src/index.js
@@ -26,7 +26,7 @@ import {
 import { randomHex } from "@miniflare/shared";
 import { coupleWebSocket } from "@miniflare/web-sockets";
 import { Headers } from "undici";
-import { WebSocketServer } from "ws";
+import { WebSocketServer } from "ws/wrapper.mjs";
 
 // packages/http-server/src/helpers.ts
 import { networkInterfaces } from "os";

tsconfig.json

{
  "compilerOptions": {
    "moduleResolution": "node",
    "lib": ["esnext"],
    "esModuleInterop": true,
    "target": "es2020",
    "strict": true,
    "skipLibCheck": true,
    "module": "esnext",
    "types": ["jest"]
  },
  "include": ["src"],
  "exclude": ["node_modules", "dist/"]
}

Have you found a solution to this? I'm stuck with the same issue.

Hey, @metawrap-dev I think this was fixed in miniflare@v2.0.0-rc.2

The import now looks like this: https://github.com/cloudflare/miniflare/blob/666a69433f6c3131b6f85ad746207846cc5c04e9/packages/http-server/src/index.ts#L337-L341

Also the patch in this gist should fix it temporarily

Thanks! I was having this issue with another project and was trying to work out if it was a problem with ws (recent changes there with @types/ws with a similar issue) or a bug in jest, but it looks like you figured it out already. Much appreciated!

Do you know if the jest team is aware of this issue?

No sorry, I don't know if they are aware. You might report it to them