Multipart upload streaming (busboy)

                  import Busboy from 'busboy';
import type { Request, Response } from 'express';

export function upload(req: Request, res: Response) {
  const bb = Busboy({ headers: req.headers, limits: { fileSize: 10 * 1024 * 1024 } });
  let bytes = 0;

  bb.on('file', (_name, stream, info) => {
    if (!['image/png', 'image/jpeg'].includes(info.mimeType)) {
      stream.resume();
      return;
    }

    stream.on('data', (chunk) => (bytes += chunk.length));
    stream.on('limit', () => res.status(413).end());
    stream.on('end', () => {
      res.status(200).json({ ok: true, bytes });
    });
  });

  req.pipe(bb);
}