Convert and Email Google Spreadsheets as Excel Files

function emailAsExcel(config) {
  if (!config || !config.to || !config.subject || !config.body) {
    throw new Error('Configure "to", "subject" and "body" in an object as the first parameter');
  }

  var spreadsheet   = SpreadsheetApp.getActiveSpreadsheet();
  var spreadsheetId = spreadsheet.getId()
  var file          = Drive.Files.get(spreadsheetId);
  var url           = file.exportLinks[MimeType.MICROSOFT_EXCEL];
  var token         = ScriptApp.getOAuthToken();
  var response      = UrlFetchApp.fetch(url, {
    headers: {
      'Authorization': 'Bearer ' +  token
    }
  });

  var fileName = (config.fileName || spreadsheet.getName()) + '.xlsx';
  var blobs   = [response.getBlob().setName(fileName)];
  if (config.zip) {
    blobs = [Utilities.zip(blobs).setName(fileName + '.zip')];
  }

  GmailApp.sendEmail(
    config.to,
    config.subject,
    config.body,
    {
      attachments: blobs
    }
  );
}