“Error: ENOENT: no such file or directory, mkdir” in deployed website

In my website I need to create a folder and save some file in it, my code works as long I’m running it in local, but once I’ve doplyed it on render I’m getting this error

Error: ENOENT: no such file or directory, mkdir '/opt/render/desktop/data/filename
[...]
Apr 24 07:37:41 PM    syscall: 'mkdir',
Apr 24 07:37:41 PM    code: 'ENOENT',
Apr 24 07:37:41 PM    path: '/opt/render/desktop/data/filename

This is the code I’m using to create the folder:

const fs = require("fs");

createFolder = (folderName) => {
  var dir = require("path").join(
    require("os").homedir(),
    `desktop/data/${filename}`
  );
  if (!fs.existsSync(dir)) {
    fs.mkdirSync(dir);
  }
};

I think the problem may be the path /opt/render/desktop/data/filename .
How can I solve it?