Auto Delete / Archive Emails in Gmail

autoDeleteGmail.js

function autoDelete() {
  console.log('Started autoDelete run.');
  var delayDays = 2;
  var maxDate = new Date();
  maxDate.setDate(maxDate.getDate()-delayDays);
  var label = GmailApp.getUserLabelByName("delete me");
  var threads = label.getThreads();
    
  if(threads.length > 0){
      console.log('Found ' + threads.length + ' emails marked for deletion.');
    var counter = 0;
    try {
      for(var i =0; i < threads.length; i++){
        if (threads[i].getLastMessageDate()<maxDate){ 
          Logger.log('deleted email: ' + threads[i].getFirstMessageSubject());
          threads[i].markUnimportant();
          threads[i].markRead();
          threads[i].moveToTrash();
          counter++;
        }
      }
       console.log('Successfully moved ' + counter + 'emails to the trash.');
    }
    catch(e){
      console.error('Could Not Start Run: ' + e);
    }
  }
  else{
    console.log('Found ' + threads.length + 'emails marked for deletion. Exiting.');
  }
}

function autoArchive() {
  console.log('Started autoArchive run.');
  var delayDays = 2;
  var maxDate = new Date();
  maxDate.setDate(maxDate.getDate()-delayDays);
  var label = GmailApp.getUserLabelByName("archive me");
  var threads = label.getThreads();
    
  if(threads.length > 0){
      console.log('Found ' + threads.length + ' emails marked for archival.');
    var counter = 0;
    try {
      for(var i =0; i < threads.length; i++){
        if (threads[i].getLastMessageDate()<maxDate){ 
          Logger.log('archived email: ' + threads[i].getFirstMessageSubject());
          threads[i].markRead();
          threads[i].moveToArchive();
          threads[i].markUnimportant();
          counter++;
        }
      }
       console.log('Successfully archived ' + counter + 'emails.');
    }
    catch(e){
      console.error('Could Not Start Run: ' + e);
    }
  }
  else{
    console.log('Found ' + threads.length + 'emails marked for archival. Exiting.');
  }
}

And just saw in the forks that someone has already done a much more complete version of this:
https://gist.github.com/zoidy/38773c6f128d4dfb94e77df99af7c446

Shoutout to @klinquist for adding a few enhancements: https://gist.github.com/klinquist/78f81e55c094111a9d3ba675c3bfd3a0