The goal is to receive an archive form the client, add a file, and upload it to Cloud Storage without creating a temporary file. The client and the server both use the archiver library. The problem with the code below is that file2.txt does not get added to the archive.

Client:

import archiver from "archiver";

const archive = archiver("zip", {
    zlib: { level: 9 },
});

archive.append("string cheese!", { name: "file1.txt" });

await fetch(`/archive`, {
    method: "POST",
    body: archive,
});

Server:

import archiver from "archiver";
import { Storage } from "@google-cloud/storage";
import { Router } from "express";

const router = Router();
const storage = new Storage();

router.post("/", (req, res) => {
  const archive = archiver("zip", {
    zlib: { level: 9 },
  });

  const cloudFile = storage.bucket("archives").file("archive.zip");

  req.pipe(archive, {
    end: false,
  });

  archive.pipe(cloudFile.createWriteStream());

  req.on("end", async () => {
    archive.append("string cheese!", { name: "file2.txt" });
    archive.finalize();
    archive.end();
  });
});