Review requested:

• @nodejs/streams

CI: https://ci.nodejs.org/job/node-test-pull-request/74768/

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.67%. Comparing base (14166a5) to head (3c2ae5a).
⚠️ Report is 111 commits behind head on main.

@@            Coverage Diff             @@
##             main   #64462      +/-   ##
==========================================
+ Coverage   90.23%   90.67%   +0.43%     
==========================================
  Files         741      744       +3     
  Lines      241375   245072    +3697     
  Branches    45483    50711    +5228     
==========================================
+ Hits       217800   222207    +4407     
+ Misses      15129    14459     -670     
+ Partials     8446     8406      -40     

... and 105 files with indirect coverage changes

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

I was under the impression that stateful transformers should not be yielding null at all, they should just mark the iterator as done to mark end-of-output?

stateful transformers should not be yielding null at all

A null output is accepted as per specification §9.3 Transforms

Transform return values are flexible. A transform may return: null (no output), Uint8Array[] (a batch), a single Uint8Array, a USVString (UTF-8 encoded), an iterable or async iterable (flattened), or a promise (awaited, async only).

And the bug is explained in #64461

@Renegade334 Would you like to create an issue on the specification?

I don't see a block from you, but I've removed author-ready.
I'll re-add it and land the fix based on your response.

Landed in 68dc116