stream: rename Duplex.toWeb() type option to readableType

[Renegade334]

The webstreams standard uses the name readableType for a source property which specifies the type of the readable component of a constructed readable-writable pair.¹ Although this is only future-proofed nomenclature at the moment, we should probably follow this convention here, for consistency and just in case we also need to support WritableStream types in the future.

This paradigm would also be consistent with Duplex.toWeb() taking readableStrategy and writableStrategy options in the future, if so desired.

Because Duplex.toWeb() is no longer marked as experimental, I believe that removing options.type entirely would need a full deprecation cycle, so I've just turned it into a silent alias for simplicity.

Refs: #58664

Footnotes

1. https://streams.spec.whatwg.org/#dictdef-transformer ↩

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.73%. Comparing base (6c44d31) to head (c16967a).
⚠️ Report is 60 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #61632      +/-   ##
==========================================
- Coverage   89.73%   89.73%   -0.01%     
==========================================
  Files         673      675       +2     
  Lines      203948   204531     +583     
  Branches    39193    39308     +115     
==========================================
+ Hits       183022   183528     +506     
- Misses      13240    13301      +61     
- Partials     7686     7702      +16     

Files with missing lines	Coverage Δ
lib/internal/webstreams/adapters.js	85.66% <100.00%> (+0.08%)	⬆️

... and 51 files with indirect coverage changes

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[Renegade334]

cc @nodejs/streams – would be grateful for eyeballs.

[MattiasBuelens]

This also came up during the initial implementation. But I agree, readableType is more future-proof. 👍

[mcollina]

Can you do it in a non-breaking way? Add the new option and keep the old one.
Add a deprecation for the old one.

[Renegade334]

Can you do it in a non-breaking way? Add the new option and keep the old one.

As stands, this silently accepts the old option as an alias to the new. Deprecation could follow, or we can keep this behaviour in perpetuity.

[MattiasBuelens]

As stands, this silently accepts the old option as an alias to the new. Deprecation could follow, or we can keep this behaviour in perpetuity.

I believe @mcollina means that the old type parameter should not yet be removed from the documentation and the JSDoc types. We want to make it clear that both readableType and type are still supported, without having to look at the Node.js source code. 😉

[Renegade334]

We want to make it clear that both readableType and type are still supported, without having to look at the Node.js source code. 😉

Would this be particularly useful?

The last precedent for this that I can recall was 68dc15e, and the documentation was just straight-up changed to reflect the renaming, even though the old name was initially left as a deprecated alias.

[jasnell]

LGTM. A couple of nits. I would recommend just going ahead and adding a docs-only deprecation for types in deprecated.md