Anyone interested… here is the code which worked for me: https://github.com/google/google-api-nodejs-client/issues/1098

Finnaly I was able to fix it… here is more info: https://stackoverflow.com/questions/49447186/exporting-file-from-google-drive-using-googleapi-in-node-js

Hi ninja :)
I have come to same problem as you 2 months ago, did you solve the Error: Required parameter: mimeType?

Thanks in advance for your reply ;)