Save Gmail Attachments on Google drive - unknown file type

Question

I looked for previous questions on this subject and found some posts from a few years ago. They don't exactly match my problem and when I try them I get more run errors than the script I am using. In my case, my script creates the files but they show up in my google drive as "unknown file" and can't be opened or previewed in Google drive. However, if I download the file to my pc, it opens and previews correctly and without any problem. How do I correct the "unknown" designation in my Google Drive?
I've tried a lot of possible solutions but either they get run time errors or I end up with an "empty" file.

Does anyone have any ideas on why this is happening or how to correct the unknown files attribute?

//pasted by Cooper as an example
function  putyourcodehere() {
  //this was posted via a ctrl-K
}

Answer 1

Save Attachment to a folder

function lfunko() {
  const query = 'subject:ThisIsATestMessage';
  Gmail.Users.Messages.list(gobj.globals.calendarid, { q: query }).messages.forEach(m => {
    GmailApp.getMessageById(m.id).getAttachments().forEach(a => {
      DriveApp.getFolderById(gobj.globals.testfolderid).createFile(a.copyBlob()).setName(a.getName());
    })
  })
}

gobj.globals is an object of global variables I use so that I don't have to redact them when used within answers that will be posted on SO. Just treat them as things you will have to replace with your own local variables. I used gobj.globals.calendarid because that's my email address which is what they want for the userid

Of course you will have to enable the Gmail API