Nodejs file download

gistfile1.txt

const fileDownload = (req, res, next) => {
    const requestedFileName = `${req.params.id}:${req.params.filename}`;
    const filePath = path.join([req.app.get('basedir'), 'storage'].join('/') , requestedFileName);

    if (!fileSystem.existsSync(filePath)) {
      return res.status(403).send({error: 'FileNotExists'}).end();
    }

    const stat     = fileSystem.statSync(filePath);
    const filename = path.basename(filePath);
    const mimetype = mime.getType(filePath);

    res.setHeader('Content-disposition', 'attachment; filename=' + filename);
    res.setHeader('Content-type', mimetype);

    const readStream = fileSystem.createReadStream(filePath);
    readStream.pipe(res);
}