inbox-zero.js

function autoArchive() {
  var archiveLabels = ["<...>"],
      deleteLabels = ["<...>"],
      maxAgeDays = 7,
      log = DocumentApp.openById("<Log Document ID>"),
      logger = log.getBody();
  
  var maxDate = new Date();
  logger.appendParagraph(maxDate.toString());
  maxDate.setDate(maxDate.getDate()-maxAgeDays);
  for (var i = 0; i < archiveLabels.length; i++) {
    var label = archiveLabels[i];
    var threads = GmailApp.search("is:read in:inbox label:" + label);
    for (var j = 0; j < threads.length; j++) {
      var thread = threads[j];
      if (thread.getLastMessageDate() <= maxDate) {
        logger.appendParagraph("Archiving Thread: " + thread.getFirstMessageSubject());
        GmailApp.moveThreadToArchive(thread);
      }
    }
  }
  for (var i = 0; i < deleteLabels.length; i++) {
    var label = deleteLabels[i];
    var threads = GmailApp.search("is:read label:" + label);
    for (var j = 0; j < threads.length; j++) {
      var thread = threads[j];
      if (thread.getLastMessageDate() <= maxDate) {
        logger.appendParagraph("Deleting Thread: " + thread.getFirstMessageSubject());
        thread.addLabel("fake-bin");
        GmailApp.moveThreadToArchive(thread);
      }
    }
  }
  logger.appendHorizontalRule();
  log.saveAndClose();
}