Clarify that the buffer is transferred by ReadableStreamBYOBReader.read()

[Kaiido]

MDN URL

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

What specific section or headline is this issue about?

Not entirely sure, maybe the top section

What information was incorrect, unhelpful, or incomplete?

There is no mention that the passed ArrayBuffer will be transferred.

What did you expect to see?

The page should probably clarify that the ArrayBuffer passed along the view will get transferred by the call to read(), making it unavailable until the actual read operation returns, where it can be gotten back from value.buffer as is being done in the example section.

I must admit I'm not sure how it should be presented though, hence this issue rather than a PR.

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

If you follow the path from https://streams.spec.whatwg.org/#byob-reader-read, you end up at https://streams.spec.whatwg.org/#readable-byte-stream-controller-pull-into where step 10 will transfer the ArrayBuffer.

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/web/api/readablestreambyobreader/read
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamBYOBReader/read
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/readablestreambyobreader/read/index.md
• Last commit: 3fcc43c
• Document last modified: 2025-04-03T13:42:39.000Z

[Josh-Cena]

This is already mentioned in the return value:

The original view will be detached and no longer usable.

Also in the introduction:

Note that once the promise fulfills, the original view passed to the method will be detached and no longer usable.

[Kaiido]

Wow, not sure how I could miss the paragraph in the description, which is exactly what I wanted to see. Somehow I searched for "transfer" instead of "detached".

Sorry for the inconvenience.