feat(streams/unstable): toByteStream()

[BlackAsLight]

This pull request introduces a small function to @std/streams that allows someone to easily upgrade a ReadableStream<Uint8Array> to support BYOB if it doesn't already.

Example

import { upgradeReadable } from "@std/streams/unstable-upgrade-readable-stream";

const reader = upgradeReadable(ReadableStream.from([
  new Uint8Array(100),
  new Uint8Array(78),
  new Uint8Array(125),
]))
  .getReader({ mode: "byob" });

reader.releaseLock()

[kt3k]

This might be useful in some cases, but I'm not sure if it's common to call this operation/util 'upgrade'...('upgrade' reminds me of upgrading http connection to websocket connection). How about calling this 'toReadableByteStream'?

@crowlKats @lucacasonato What do you think about this?

[BlackAsLight]

toByteStream is a slightly shorter name.

I use a similar function a lot in the cbor pull request and thought it's unique enough and useful enough to offer as a utility.

I also found if you don't end up enqueuing or responding in each pull then you end up with that promise left in the event loop error.

[kt3k]

toByteStream sounds good to me

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.76%. Comparing base (ea85486) to head (2fd5a88).
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6046      +/-   ##
==========================================
+ Coverage   96.75%   96.76%   +0.01%     
==========================================
  Files         508      509       +1     
  Lines       39140    39185      +45     
  Branches     5793     5803      +10     
==========================================
+ Hits        37869    37917      +48     
+ Misses       1229     1226       -3     
  Partials       42       42              

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[BlackAsLight]

I'd just like to say that getting this function right was quite hard as there always seemed like another hiccup.

I've found that when using the min property, value will always be a Uint8Array, even when done is true and TypeScript infers it might be undefined. value is still a Uint8Array, even if that length is zero. value when done is true will contain the amount it was able to get that's less than min.

[kt3k]

LGTM. Thanks!