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Title: stream: speed up WHATWG web streams by anonrig · Pull Request #65273 · nodejs/node · GitHub

Open Graph Title: stream: speed up WHATWG web streams by anonrig · Pull Request #65273 · nodejs/node

X Title: stream: speed up WHATWG web streams by anonrig · Pull Request #65273 · nodejs/node

Description: Leftover construction-path work on node:stream/web after #65138 landed the shared hot-path reductions (thenAlgorithmResult, kResolvedPromise, raw pull/write callbacks, parkOnReady). Rebased onto current main, including #65143 (transform backpressure decoupling). That PR's raw defaultTransformAlgorithm / createRawCallback2Params path is kept. The earlier body described work that is no longer in this tree (pipeTo sync-fill, write-queue drain, native webstreams binding, shared kResolvedPromise on public slots). This is what remains. What remains Deferred empty ReadableStream controller. new ReadableStream() with no source/strategy skips validateObject and does not allocate a default controller until getReader(), cancel() (only while readable), pipeTo(), tee(), or values(). createReadableStreamState() initializes controller: undefined so empty and non-empty streams share the same hidden class. Interop error() on an empty stream marks it errored without materializing a controller. Subclasses that call those methods after super() still get a controller before the subclass constructor finishes; passing a source leaves this path and creates the controller during super() as usual. Cheaper empty WritableStream / TransformStream construction. Skip validateObject on the shared empty sentinels. The writable AbortController is created lazily and materialized on abort() or first controller.signal access, so a signal observed after abort is still aborted with that reason. isNonThenable() stays in JS. Shared helper for start/pull/write results. null / primitives take the allocation-free kResolvedPromise reaction; objects and functions stay on the maybe-thenable path (no observable .then lookup). There is no native webstreams binding. Review follow-up (removed) Addressed #65273 (comment): readableStreamDefaultControllerFillSync is gone (one pull per microtask) pipeTo write-queue drain loop is gone (one write completion per microtask) writer.ready / writer.closed / cancel() mint distinct promises (no shared kResolvedPromise) cancel/close/abort/flush/transform keep async wrappers so thenable results keep the previous microtask count native internalBinding('webstreams') removed; cloneAsUint8Array is still the JS ArrayBuffer.prototype.slice path (detached buffers stay TypeError) Semver The earlier semver-major concerns were the removed fillSync / drain / shared-promise / timing-helper changes. Public constructors, methods, and WHATWG Streams behavior (backpressure, BYOB, pipeTo, tee, errors, transfer) are intended to be unchanged. @MattiasBuelens noted the remaining scope does not look semver-major. Benchmarks The numbers previously posted here were measured against a base that predates #65138 and included the removed optimizations. They are not this PR's remaining delta. A full webstreams/ compare against current main still needs to be posted. Tests test/wpt/test-streams.js test/parallel/test-whatwg-readable*, writable*, transform*, webstreams*, test-webstreams*, test-global-webstreams.js new test/parallel/test-whatwg-webstreams-hotpath.js (public read() / pipeTo, deferred controller / subclass constructors, isNonThenable / Proxy, cloneAsUint8Array edge cases, abort-before-signal, distinct writer.ready / writer.closed / cancel() promises) abort-before-signal case in test-whatwg-writablestream.js AI assistance This change was developed with assistance from Grok. I reviewed, tested, and take responsibility for the submitted code.

Open Graph Description: Leftover construction-path work on node:stream/web after #65138 landed the shared hot-path reductions (thenAlgorithmResult, kResolvedPromise, raw pull/write callbacks, parkOnReady). Rebased onto cu...

X Description: Leftover construction-path work on node:stream/web after #65138 landed the shared hot-path reductions (thenAlgorithmResult, kResolvedPromise, raw pull/write callbacks, parkOnReady). Rebased onto cu...

Opengraph URL: https://github.com/nodejs/node/pull/65273

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