Image compression using sharp in node js

Question

I am building an app in flutter where user can upload image of max-size 20mb and want image to be compressed before storing it on server side. Basically compression will be done at server site.

Ive tried sharp but it couldn't compressed even a single byte. Above is the code

module.exports = function resize(path, format, width, height) {
  const readStream = fs.createReadStream(path);
  let transform = sharp(path).png({
    compressionLevel: 9,
    adaptiveFiltering: true,
    force: true,
    quality: 80,
  }).withMetadata().toFile('output.png',function(err){
      console.log("error :- ",err);
  });

  return readStream;
};

Is image compression is possible using sharp?