ExpressJS Res.Download() Not Sending File to Download

I am trying to download the file from expressjs backend using Axios. The file is of size 1kB but on attempting to download it every time, I am getting 17 bytes file that does not open.

Here is my backend code:

const __dirname = path.resolve();

app.get("/download", function(req, res, next) {

        const dirPath = `${__dirname}/images/${req.query.dir}/output`;

        let files = fs.readdirSync(dirPath);

        res.download(`${dirPath}/${files[0]}`);

        res.status(200).send("Download complete");
});

And my frontend code is:

axios({
      url: `http://example.com/download?dir=${someDir}`,
      method: "GET",
      responseType: "blob"
    })
      .then(res => {
        //console.log(res.data);
        const href = URL.createObjectURL(res.data);
        //console.log(href);
        
        const link = document.createElement("a");
        link.href = href;
        link.setAttribute("download", output.jpeg);
        document.body.appendChild(link);
        link.click();

        document.body.removeChild(link);
        URL.revokeObjectURL(href);
      })
      .catch(er => console.log(er));

I am puzzled to find the root cause of this. Help on this appreciated