How to get the most recent Gmail message in Google Apps Script?

The docs are thin.

Using GAS, how do I get the most recent Gmail message in my inbox matching a specific subject string?

function getConfig() {
  var email = {
    subject: 'My subject string', 
  };
  email.q = [
    [ 'label'   , 'inbox'       , ].join(':'),
    [ 'subject' , email.subject , ].join(':'),
  ].join(' ');
  var config = {
    me: 'me',
    email: email
  };
  return config;
}

function getMessages() {
  var config = getConfig();
  var me = config.me;
  var email = config.email;
  var q = email.q;
  var msgs = Gmail.Users.Messages.list(me, {
    q: q,
  });
  Logger.log('Messages length: %s', msgs.length); // undefined
}

As you can see, the logger returns undefined.

You can use GmailApp to get the Messages. It will return you data in an array and you can easily sort it.

Also, you can search the messages by passing a specific query.

Document Link

Hope it helps!.