Gmail Inbox maintenance - automatically cleans up older email notifications that have only a transient use - either by sender or by filter-folder

gmailautocleanup.js

// adapted from idea in https://gist.github.com/anonymous/2cca33d376f7f924fdaa67891ad098cc

function EmailIdFromMailer(mailer)
{
  var start = mailer.indexOf('<');
  var end = mailer.indexOf('>');
  if (start > -1 && end > -1)
  {
    return mailer.substring(start+1,end);
  }
  return mailer
}

function gmailAutoCleanup() 
{
  var archiveDelayDays = 5; // will only impact emails more than 5d old
  var archiveFromSender = ['[email protected]','[email protected]'] // add others as you see fit
  var trashDelayDays = 30; // will only impact emails more than 30d old
  var trashFolders = ['Social', 'online shopping']
  var considerMsgWindow=60; //only messages in last 2 months will be processed.

  
  var archiveThresholdDate = new Date();
  archiveThresholdDate.setDate(archiveThresholdDate.getDate()-archiveDelayDays);

  // Get first 400 emails from one-off notifiers and mostly-spammers
  var threads = GmailApp.getInboxThreads(0,400);
  if (threads == null || threads == undefined) return -1;

  // we archive all the threads if they're unread AND older than the limit we set in delayDays
  for (var i = 0; i < threads.length; i++) 
  {
    messages = threads[i].getMessages();
    if (messages == null || messages.length == 0)
    {
      Logger.log("*** Null messages...skipping");
      continue;
    }
    if (threads[i].getLastMessageDate() < new Date() - considerMsgWindow) break;
    
    var mailer=EmailIdFromMailer(messages[0].getFrom());
    //Logger.log("considering '%s'...%s < %s", mailer, threads[i].getLastMessageDate(),archiveThresholdDate);
    if (archiveFromSender.indexOf(mailer) > -1 && threads[i].getLastMessageDate() < archiveThresholdDate)
    {
      if (!threads[i].hasStarredMessages() && !threads[i].isImportant())
      {
        threads[i].markRead();
        threads[i].moveToArchive();
        Logger.log("Archiving thread %s : %s", messages[0].getFrom(), threads[i].getFirstMessageSubject());
      }
      else
      {
        Logger.log("Retaining (important/starred) thread %s : %s", messages[0].getFrom(), threads[i].getFirstMessageSubject());
      }
    }
    else
    {
      //Logger.log("      Retaining thread %s : %s", messages[0].getFrom(), threads[i].getFirstMessageSubject());
    }
  }
  
  var trashThresholdDate = new Date();
  trashThresholdDate.setDate(trashThresholdDate.getDate()-trashDelayDays);
  
  // Get emails in folders listed above
  for (lbl in trashFolders)
  {
    var threads = GmailApp.getUserLabelByName(lbl);
    if (threads == null || threads == undefined) continue;
    for (var i = 0; i < threads.length; i++) 
    {
      messages = threads[i].getMessages();
      if (messages == null || messages.length == 0) continue;
      if (threads[i].getLastMessageDate() < new Date() - considerMsgWindow) break;
      
      if (threads[i].getLastMessageDate() < trashDelayDays && !threads[i].hasStarredMessages() && !threads[i].isImportant())
      {
        Logger.log("Trashing thread %s : %s", messages[0].getFrom(), threads[i].getFirstMessageSubject());
        threads[i].moveToTrash();
      }
      else
      {
        Logger.log("Not trashing thread %s : %s", messages[0].getFrom(), threads[i].getFirstMessageSubject());
      }
    }
  }
  
  if (Logger.getLog().length > 0)
  {
    var email = Session.getActiveUser().getEmail(); # your email id
    GmailApp.sendEmail(email, 'Auto-email Cleanup', 
                       Logger.getLog() +
                       "Please restore trashed items within 30d.\nStar or mark important to prevent archival from Inbox or trashing from folder\n");
  }
}