How to convert this file path in buffer format

I am converting this file path data into buffer format. I am sending this data to server but server needs buffer format data. Anyone knows how to do this converting of file path into buffer format.

const chooseFile = async () => {
  try {
    const res = await DocumentPicker.pick({
      type: [DocumentPicker.types.images]
    });
    console.log("res : " + JSON.stringify(res));
  } catch (err) {
    setFile(null);
    if (DocumentPicker.isCancel(err)) {
    } else {
      throw err;
    }
  }
};
console.log("file", file);
const buffer = new Buffer.from(file);
console.log("Buffer", buffer);