Hoist _children into a local in constructNewChildrenArray - #5198
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Size Change: -5 B (-0.03%) Total Size: 15.9 kB 📦 View Changed
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Every normalization branch in the loop wrote through `newParentVNode._children[i]`, reloading the property each time. Bind it once and write through the local instead. -5 B brotli (4582 -> 4577), performance-neutral across update, mount, keyed-reorder and hydration benchmarks. This replaces the earlier "avoid allocating arrays for single children" approach from this branch. Passing the single child unwrapped did win 3-7% on update10th1k, but it cost ~3% on first-paint hydration, so it was dropped. For the record, hydrate1k's reported 45-55% regression on that earlier version was a measurement artifact, not a throughput regression: the benchmark does exactly 5 warmup hydrations and times the 6th, and each iteration clones and discards ~8000 DOM nodes, which produces a deterministic periodic slow hydration every ~4-5 iterations. Each build has its own phase. Timing only #6 sampled the patched build's slow phase. Holding the build pair fixed and varying only the warmup count gave -16.8% / +30.8% / +6.4% / +0.9% / -21.8% / +7.0% for hydrations 5-10 (mean ~+1%), while a main-vs-main control over the same protocol stayed flat at +0.2% / -0.5% / -1.3%. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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JoviDeCroock
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_children into a local in constructNewChildrenArray
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coverage: 99.297%. remained the same — JoviDeCroock/issue-2618-algo-learnings into main |
JoviDeCroock
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August 7, 2026 04:02
marvinhagemeister
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Every normalization branch in
constructNewChildrenArray's loop wrote throughnewParentVNode._children[i], reloading the property on each branch. Bind it once and write through the local instead.−5 B brotli (4582 → 4577), performance-neutral everywhere.
Fixed up by Claude opus