Google Apps Script to mark all non-starred unread emails as read

code.gs

function getInboxUnreadCount() {
  Logger.log(GmailApp.getInboxUnreadCount() + " unread emails");
}

function setAllUnreadNonStarredAsRead() {
// Define the search string to identify emails 
  var searchString = "is:unread -is:starred in:inbox";

  // Get all threads matching search string
  var threads = GmailApp.search(searchString,0,500);
  for (var i=0; i<threads.length; i++) {
    var thread = threads[i];
    Logger.log(Utilities.formatDate(thread.getLastMessageDate(),"GMT","yyyy-MM-dd") + " : " + thread.getFirstMessageSubject());
    if (threads[i].hasStarredMessages()) {
      Logger.log("  ➰ Starred so skipped")
    } else {
      threads[i].markRead()
      Logger.log("  ✅ Marked as read")
    }
  }
}

getInboxUnreadCount()
// this will only do 500 at a time, but I'll just keep running it
setAllUnreadNonStarredAsRead()