Error "SyntaxError: Cannot use import statement outside a module" when using node-fetch in Jest with Typescript

[roblframpton]

I am trying to write an integration test in Typescript with Jest which uses node-fetch, like this:

import fetch from 'node-fetch';

test('Hello', async () => {
    await fetch("http://www.google.com");
});

But I am getting the following error:

Jest encountered an unexpected token

[...]

Details:

/home/xxx/node_modules/node-fetch/src/index.js:9
import http from 'node:http';
^^^^^^

SyntaxError: Cannot use import statement outside a module

> 1 | import fetch from 'node-fetch';
    | ^
  2 |
  3 | test('Hello', async () => {
  4 |     await fetch("http://www.google.com");

  at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1796:14)
  at Object.<anonymous> (temp.test.ts:1:1)

I believe this is specifically a problem with node-fetch because it only affects imports from this package. For example, I can do import express from 'express' without any difficulty.

Reproduction

Steps to reproduce the behavior:

1. Run the following:

npm init
npm install --save-dev jest typescript ts-jest @types/jest node-fetch @types/node-fetch
npx ts-jest config:init

2. Create the file temp.test.ts:

import fetch from 'node-fetch';

test('Hello', async () => {
    await fetch("http://www.google.com");
});

3. Run npx jest

Expected behavior

The test calls fetch

Your Environment

software	version
node-fetch	3.2.6
node	v16.0.0
npm	8.5.5
jest	28.1.1
Operating System	Windows 10 x64

[roblframpton]

I solved this - it was not an issue with node-fetch, apoligies. See here if you need the solution.

[corderop]

I don't think this has been resolved. It's still happening to me. I don't think the solution is to downgrade the library to the 2.x version.

We will need to upgrade at any moment, which will continue to fail. Is there any solution to get this working with 3.x version?

[jimmywarting]

An alternative method is switching to using NodeJS v18 \w built in fetch, FormData, and the rest. it's more spec compliant using web streams instead.

[corderop]

@jimmywarting I didn't know that Node v18 comes with built-in fetch. I will consider switching instead of migrating to the 3.x version.

However, thanks to your fantastic effort with this library. It helped me solve particular problems I was facing with other libraries.

[Plausiblebowhead26]

After a thorough search, I found the answer to my question

https://nodeer.space/questions/typescript-when-using-ts-node-dev-an-error-occurred-while-trying-to-import-express-due-to-an-unexpected