fitler_gh_notifications.js

function filterGhNotifications() {
  var sourceLabel = GmailApp.getUserLabelByName('GH');
  var addedLabel = GmailApp.getUserLabelByName('GH -- mde');
  var pat = /@mde/;
  var threads;
  var foundThreads = [];
  threads = sourceLabel.getThreads(0, 20);
  threads.forEach(function (thread) {
    var messages = thread.getMessages();
    var subject;
    var found = messages.some(function (message) {
      subject = message.getSubject();
      return pat.test(message.getBody());
    });
    if (found) {
      foundThreads.push({
        obj: thread,
        subj: subject
      });
    }
  });

  Logger.log('Found ' + foundThreads.length + ' matching threads');
  Logger.log('Adding to ' + addedLabel.getName());
  foundThreads.forEach(function (thread) {
    addedLabel.addToThread(thread.obj);
    Logger.log('Added ' + thread.subj);
  });
}