Unable to import ESM-only modules in a test

What is your Scenario?

Importing ESM-only modules in a test throws ERR_REQUIRE_ESM error.

What is the Current behavior?

An error is thrown:

Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: node_modules\node-fetch\src\index.js
require() of ES modules is not supported.
require() of node_modules\node-fetch\src\index.js from test.js is an ES module file as it is a .js file whose nearest parent package.json contains "type": "module" which defines all .js files in that package scope as ES modules.
Instead rename index.js to end in .cjs, change the requiring code to use import(), or remove "type": "module" from node_modules\node-fetch\package.json.

    at Object.<anonymous> (test.js:3:1)

What is the Expected behavior?

Test executes correctly.

What is your public website URL? (or attach your complete example)

Please see the isolated test code below.

What is your TestCafe test code?

// Make sure node-fetch 3.2.0 is installed.
// It is an ESM-only module.
import fetch from 'node-fetch' // The test will fail at this line.

fixture`ESM-only module import error`

test('Will not run', () => {
  console.log('This code will not run')
})

Your complete configuration file

No specific configuration file.

Your complete test report

Please refer to the error message above.

Screenshots

Not applicable.

Steps to Reproduce

Please install node-fetch 3.2.0 and run the attached test code.

TestCafe version

1.18.3

Node.js version

14.17.1

Command-line arguments

testcafe chrome test.js

Browser name(s) and version(s)

chrome

Platform(s) and version(s)

Windows 11

Other

The test code runs with node-fetch 2.6.7, which supports require(). It seems that import statements are transpiled to require calls, which fails for all ESM-only modules.

[puneetpunj]

Any update on this issue? this is happening with @percy/testcafe package as well.

[AlexKamaev]

@bvklingeren, You are right, a fix for this issue might take significant time. We did not look into it yet. We have plans to research it, but I cannot give time estimates right now, unfortunately.