cannot read form data with `readFormData` on vercel edge

[pi0]

Moving from https://github.com/unjs/nitro/discussions/1718 reported by @cosbgn

Minimal reproduction:

routes/index.ts:

export default defineEventHandler(async (event) => {
  if (event.method === "POST") {
    return await readFormData(event)
      .then((r) => r.get("name"))
      .catch((e) => e.stack);
  }
  return `
  <script type="module">
    console.log('Fetching...')
    const data = new FormData();
    data.append("name", "John Doe");
    const res = await fetch("/", { method: 'POST', body: data });
    const text = await res.text();
    console.log('Fetch complete: ' + text) 
    alert(text)
  </script>
  <h1>Check Console</h1>
`;
});

(checking console, response never handles)

Workaround

You can use the older readMultipartFormData utility. It returns an array of form datas:

export default defineEventHandler(async (event) => {
  if (event.method === "POST") {
    return await readMultipartFormData(event)
      .then((data) =>
        data.find((d) => d.name === "name")?.data.toString("utf8")
      )
      .catch((e) => e.stack);
  }
  return `
  <script type="module">
    console.log('Fetching...')
    const data = new FormData();
    data.append("name", "John Doe");
    const res = await fetch("/", { method: 'POST', body: data });
    const text = await res.text();
    console.log('Fetch complete: ' + text)
    alert(text)
  </script>
  <h1>Check Console</h1>
`;
});

https://nitro-ppspi2qf2-pi0.vercel.app/