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perf: optimize array mutations and repeat reconciliation - #7784
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John Kreitlow (radium-v) wants to merge 1 commit into
Open
John Kreitlow (radium-v) wants to merge 1 commit into
John Kreitlow (radium-v) wants to merge 1 commit into
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- Reduce sort bookkeeping and large-array splice normalization costs - Compose reorders and minimize DOM moves while retaining stable views - Fix mixed mutation batches and repeat positioning updates - Add regression tests and CSR/SSR mutation benchmarks
John Kreitlow (radium-v)
requested review from
Chris Holt (chrisdholt) and
Jane Chu (janechu)
as code owners
October 28, 2026 05:10
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There are additional existing repeat bugs that have been discovered out of this investigation. I'm testing fixes for them now. This PR may get split up. |
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Pull Request
📖 Description
Reduce array-observation and repeat-rendering overhead for large or frequently mutated lists. Optimize sort bookkeeping, large-array splice normalization, and view reconciliation while preserving item-view associations and keeping stable views mounted.
Fix mixed reorder/splice batches so subscribers reconcile against the final array, and refresh repeat positioning metadata after reorders.
Add regression tests and observer-only, CSR/SSR mutation, and hydration benchmarks. Update design documentation, API documentation, and export-size reports.
📑 Test Plan
BENCH_ITERATIONS=20 npm run bench -w @microsoft/fast-bench -- repeat-mutations.✅ Checklist
General
$ npm run changeAgents