How to send music from express server to website?

Question

JavaScript

I want to get a song from the server to the site: All songs are stored in a certain folder, and I want to get the first one in the folder:
<audio src="/getAudio" controls></audio>

app.get("/getAudio", (req, res) => {
    const files = fs.readdirSync(__dirname, "uploads");
    res.sendFile(files[0]);
});

But it gives me an error 500. How can I fix this?