Generate Google JWT from nodejs

Question

I'm trying to create a micro-service on Node to send requests on the Google Compute API via POST (for example here). This micro-service will be hosted on a App Engine application.

If I understand the documentation, I need to generate a JWT token before (with the google-auth-library) and send that token with the request.

I set up the env variable GOOGLE_APPLICATION_CREDENTIALS with the JSON file path of the Service Account used by the App Engine application on my debugger (to get the same authorization on my dev env).

But I can't reproduce the sample hosted on Github gave by the Google Documentation. I get error UnhandledPromiseRejectionWarning: ReferenceError: require is not defined because I'm using Node14 with "type": "module" on the package.json.

I searched but I found no solution on this. Do you have some hint ? Maybe I need to use a different code to generate JWT token or to authentificate these POST requests ?

Thank you