Avoid traversing retained subtrees - #5182
Merged
Merged
Conversation
Use getDomSibling to recover the position after a retained subtree instead of recursively walking it through insert(). Keep leaf VNodes on the direct nextSibling path and reserve insert() for actual placements. PR #5172 independently improves keyed reordering on v10.x and is not included in this branch.
📊 Tachometer Benchmark ResultsSummaryduration
usedJSHeapSize
Resultscreate10kduration
usedJSHeapSize
filter-listduration
usedJSHeapSize
hydrate1kduration
usedJSHeapSize
many-updatesduration
usedJSHeapSize
replace1kduration
usedJSHeapSize
run-warmup-0
run-warmup-1
run-warmup-2
run-warmup-3
run-warmup-4
run-final
text-updateduration
usedJSHeapSize
tododuration
usedJSHeapSize
update10th1kduration
usedJSHeapSize
|
|
Size Change: -86 B (-0.11%) Total Size: 79.4 kB 📦 View Changed
ℹ️ View Unchanged
|
- Inline the now single-use shouldPlace flag - Use insertBefore's return value to set oldDom in insert() - Set oldDom via getDomSibling directly in diff()'s bailout block so the retained-children identity branch in diffChildren can be dropped; the existing result branch picks it up -12 B gzip / -16 B brotli on preact.min.js
marvinhagemeister
approved these changes
Jul 30, 2026
jviide
pushed a commit
to jviide/preact
that referenced
this pull request
Jul 30, 2026
Port of preactjs#5182 to v11. On a successful shouldComponentUpdate/memo bailout, set oldDom via getDomSibling directly in diff()'s bailout block instead of recursively walking the retained child tree through insert(); the existing result branch in diffChildren picks it up. Actual placements still use insert(), which now only handles placement and drops its shouldPlace flag. -20 B gzip / -18 B brotli on preact.mjs
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Use
getDomSibling()after successfulshouldComponentUpdate/memo bailouts instead of recursively walking retained child trees throughinsert(). Actual placements still useinsert().