akamyshanov

function gmailAutoarchive() {
  var threads = GmailApp.search("in:inbox label:auto-archive older_than:2d");
  
  Logger.log("found " + threads.length + " threads:");
  for(var i = 0; i < threads.length; i++) {
   var thread = threads[i];
   Logger.log((i+1) + ". " + thread.getFirstMessageSubject());
  }
  
  var batch_size = 100;

gmailAutoarchive.js

function gmailAutoarchive() {
  
  var delayDays = 2; // will only impact emails more than 48h old
  var maxDate = new Date();
  maxDate.setDate(maxDate.getDate()-delayDays); // what was the date at that time?

  // Get all the threads labelled 'autoarchive'
  var label = GmailApp.getUserLabelByName("autoarchive");
  var threads = label.getThreads(0, 400);