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stream: drop per-chunk Promise alloc in pipeTo #63572

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stream: drop per-chunk Promise alloc in pipeTo #63572

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52772fe
stream: drop per-chunk Promise alloc in pipeTo
mcollina May 25, 2026
7932aae
stream: import markPromiseAsHandled directly in pipeTo
mcollina May 28, 2026
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10 changes: 7 additions & 3 deletions lib/internal/webstreams/readablestream.js
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,10 @@ const {
DOMException,
} = internalBinding('messaging');

const {
markPromiseAsHandled,
} = internalBinding('util');

const {
isArrayBufferView,
isDataView,
Expand Down Expand Up @@ -1569,9 +1573,9 @@ function readableStreamPipeTo(
}

// Write the chunk - we're already in a separate microtask from enqueue
// because we awaited writer[kState].ready.promise above
// because we awaited writer[kState].ready.promise above.
state.currentWrite = writableStreamDefaultWriterWrite(writer, chunk);
setPromiseHandled(state.currentWrite);
markPromiseAsHandled(state.currentWrite);

// Check backpressure after each write
if (dest[kState].backpressure) {
Expand Down Expand Up @@ -1675,7 +1679,7 @@ class PipeToReadableStreamReadRequest {
// "ReadableStreamPipeTo" step 15's "chunk steps".
queueMicrotask(() => {
this.state.currentWrite = writableStreamDefaultWriterWrite(this.writer, chunk);
setPromiseHandled(this.state.currentWrite);
markPromiseAsHandled(this.state.currentWrite);
this.promise.resolve(false);
});
}
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