MailParser attachment arrives without filename

[stavbi1]

The problem:

MailParser attachment arrives without the filename

The code:

const processAndWriteStream = async (stream: SMTPServerDataStream) => {
  const parser = new MailParser();

  parser.on('data', async data => {
    if (data.type === 'attachment') {
      const filename = data.filename; // is undefined and I don't know why ):

      await writeToFile(filename, data.content); // Works fine! but the filename is undefined
      data.release();
      stream.end();
    }
  });

  stream.pipe(parser);
}