form-data for multipart/mixed

prog.ts

import fs from "fs";
import path from "path";
import FormData from 'form-data';

const main = async () => {
  const file = fs.readFileSync(path.resolve(__dirname, '../../scripts/example.txt.zip'));

  const form = new FormData();
  form.append('data', file.toString('base64'), {
    filename: 'example.txt.zip',
    contentType: 'application/octet-stream; charset=utf-8',
    header: {
      'Content-Transfer-Encoding': 'binary'
    }
  });
  form.append('username', 'john', {
    contentType: 'text/plain'
  });
  form.append('password', 'pass', {
    contentType: 'text/plain'
  });

  form.submit({
    host: 'localhost',
    port: '3000',
    path: '/p',
    headers: {
      'Content-Type': 'multipart/mixed; boundary=' + form.getBoundary()
    }
  }, (err, res) => {
    console.log(res.statusCode);

    let c = ""
    res.on('data', (chunk) => {
      c += chunk
    })
    res.on('end', () => {
      console.log(c)
    })
  });
}

main().then(() => {
  console.log('done');
}).catch(err => {
  console.log(err);
});