Missing Request constructor duplex option

[dcecile]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/Request/Request

What specific section or headline is this issue about?

Parameters

What information was incorrect, unhelpful, or incomplete?

The spec has a duplex option, but it's missing from the page

What did you expect to see?

A note about the parameter, and that it needs to be set to "half" when using a ReadableStream body.

It would also be nice to have a row for browser compatibility.

Do you have any supporting links, references, or citations?

Spec: https://fetch.spec.whatwg.org/#request-class
Chrome docs (showing how to do half-duplex fetch): https://developer.chrome.com/docs/capabilities/web-apis/fetch-streaming-requests
Related web platform test: https://wpt.fyi/results/fetch/api/request/request-init-stream.any.html?label=master&label=experimental&aligned&q=request-init-stream

Do you have anything more you want to share?

The Request class itself also has a duplex get-only property, so main page (https://developer.mozilla.org/en-US/docs/Web/API/Request) is affected and an instance property page is missing too

MDN metadata

Page report details

• Folder: en-us/web/api/request
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/Request
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/request/index.md
• Last commit: 261317e
• Document last modified: 2023-09-16T16:24:12.000Z

[Josh-Cena]

None of the browsers implement it yet. Check the browser bugs linked in whatwg/fetch#1493.

[dcecile]

Based on this test, I think Blink has the duplex constructor option implemented?

test((t) => {
  const body = new ReadableStream();
  assert_throws_js(TypeError,
                   () => new Request("...", { method, body }));
}, "It is error to omit .duplex when the body is a ReadableStream.");

https://github.com/web-platform-tests/wpt/blob/faa6d42ce21d126155dee771786ad7c74efbcba5/fetch/api/request/request-init-stream.any.js#L79-L83

https://wpt.fyi/results/fetch/api/request/request-init-stream.any.html?label=master&label=experimental&aligned&q=request-init-stream

[skyclouds2001]

also, the Request.duplex property is also missing

[skyclouds2001]

I think this should start to add an entry in bcd first (like init.duplex parameter), in mdn/browser-compat-data#25488