gmail - delete emails in threads

delete.gs

function dothedew() {
  emptyGmail();
  deleteTrashEmailsPermanently();
}

function emptyGmail() {
  var mymail = "[email protected]";
  var labels = ['INBOX', 'Archive/CSV', 'Archive/Purchase', 'Builder', 'Junk', 'Logwatches', 'MySQL', 'Notes' ]; // Add your labels here
  labels.forEach(function(label) {
  var pageToken;
    do {
      processEmail('in:' + label , 'moveThreadsToTrash');
    } while (pageToken);
  })
}

function deleteEmailsPermanently(emailThread) {
  Gmail.Users.Threads.remove('me', emailThread.getId());
}

function deleteTrashEmailsPermanently() {
  do {
    var trashMailThreads = GmailApp.getTrashThreads(0,400);
    console.log('Got a list with size: ', trashMailThreads.length);

    console.log('Now Deleting Trash Emails permanently');
    trashMailThreads.forEach((trashMailThread) => {
      console.log('Deleting email thread with Subject :', trashMailThread.getMessages()[0].getSubject());
      deleteEmailsPermanently(trashMailThread);
    });
  } while (trashMailThreads.length>0)
}

function processEmail(search, batchAction) {
  var batchSize = 100; // Process up to 100 threads at once
  var searchSize = 400; // Limit search result to a max of 500 threads. (google doesn't allow more)
  do {
    var threads = GmailApp.search(search, 0, searchSize);
    console.log('processing ' + threads.length + ' threads');
    for (j = 0; j < threads.length; j += batchSize) {
      console.log('removing batch: ' + j + '-' + Number(j + batchSize));
      GmailApp[batchAction](threads.slice(j, j + batchSize));
    }
    console.log('done with search size: ' + threads.length);
  } while (threads.length>0) // keep script running until there are no threads left
}