lib,streams: check SharedArrayBuffer existence in fast-utf8-stream

[codebytere]

Refs #58897

Fixes the following error:

"Uncaught ReferenceError: SharedArrayBuffer is not defined"

caused by changes in the above PR that declare const kNil = new Int32Array(new SharedArrayBuffer(4)); when lib/internal/streams/fast-utf8-stream.js is imported and Utf8Stream() is used. This causes an error in any environment missing a SharedArrayBuffer.

I used an alternative sleep implementation in the missing case, but am happy to rework this however is preferred.

[nodejs-github-bot]

Review requested:

• @nodejs/streams

[aduh95]

Is the haveSAB variable useful?

Suggested change

	const haveSAB = typeof SharedArrayBuffer !== 'undefined';
	const kNil = haveSAB ? new Int32Array(new SharedArrayBuffer(4)) : null;
	const kNil = SharedArrayBuffer && new Int32Array(new SharedArrayBuffer(4));

[codebytere]

@aduh95 we need it below to choose sleep implementation, no?

[aduh95]

We could use kNil for that

[targos]

The suggested code would throw an error if SharedArrayBuffer is not defined.

[aduh95]

It is declared above, it wouldn't throw even if undefined:

node/lib/internal/streams/fast-utf8-stream.js

Line 15 in 6547f21

SharedArrayBuffer,

[mcollina]

lgtm

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.58%. Comparing base (ddbe136) to head (6547f21).
⚠️ Report is 30 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/streams/fast-utf8-stream.js	50.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60453      +/-   ##
==========================================
- Coverage   88.59%   88.58%   -0.01%     
==========================================
  Files         704      704              
  Lines      207774   207831      +57     
  Branches    40035    40044       +9     
==========================================
+ Hits       184068   184107      +39     
- Misses      15748    15761      +13     
- Partials     7958     7963       +5     

Files with missing lines	Coverage Δ
lib/internal/streams/fast-utf8-stream.js	73.91% <50.00%> (-0.30%)	⬇️

... and 39 files with indirect coverage changes

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