Outlook Headers retrieval start...

retrieve.js

  var queryParams = {
    '$select': 'Subject,ReceivedDateTime,From,SingleValueExtendedProperties',
    '$orderby': 'ReceivedDateTime desc',
    '$top': 10,
    '$expand': 'SingleValueExtendedProperties($filter=PropertyId eq \'String 0x7D\')'
  };
  var token = req.session.access_token;
  var email = req.session.email;
// Set the API endpoint to use the v2.0 endpoint
outlook.base.setApiEndpoint('https://outlook.office.com/api/v2.0');
// Set the anchor mailbox to the user's SMTP address
outlook.base.setAnchorMailbox(email);
outlook.mail.getMessages({token: token, odataParams: queryParams},
  function(error, result){
    result.value.forEach(function(message) {
      console.log('Properties: ' + message.SingleValueExtendedProperties);
    }
  })