perf(RenderHTML): reduce HTML post-processing from 6 passes to 3#90305
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Hoist 4 inline regex literals to module-level constants (eliminates per-call recompilation) and merge related pairs of replaceAll calls: - Bracket unescaping: 2 literal replaceAlls → 1 regex pass - Emoji tag deduplication: 2 regex replaceAlls → 1 combined regex - <br> cleanup inside <ul>: 2 regex replaceAlls → 1 combined regex Benchmark on a ~109 KB synthetic payload: ~31% throughput improvement. Co-authored-by: Cursor <cursoragent@cursor.com>
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| // Strip orphaned <br/> tags inside <ul> that would render as extra empty bullets | ||
| .replaceAll(/<br\s*\/?>\s*(<\/ul>)/gi, '$1') | ||
| .replaceAll(/(<\/li>)\s*<br\s*\/?>\s*(?=<(?:li|\/ul)>)/gi, '$1') | ||
| .replaceAll(RE_BR_CLEANUP, '$1$2') |
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When a list contains consecutive orphaned breaks before the closing </ul> (for example from pasted/blank-line list HTML like </li><br><br></ul>), the merged single-pass regex only removes the last <br> and leaves </li><br></ul>. The previous two-pass logic first removed the <br> before </ul> and then removed the newly exposed <br> after </li>, so this reintroduces the extra empty bullet the cleanup is meant to prevent.
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Screenshots/VideosAndroid: HybridAppAndroid: mWeb ChromeiOS: HybridAppiOS: mWeb SafariMacOS: Chrome / Safari |
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✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release. |
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🚧 @tylerkaraszewski has triggered a test Expensify/App build. You can view the workflow run here. |
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🧪🧪 Use the links below to test this adhoc build on Android, iOS, and Web. Happy testing! 🧪🧪
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🚀 Deployed to staging by https://github.com/tylerkaraszewski in version: 9.3.73-0 🚀
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🚀 Deployed to staging by https://github.com/tylerkaraszewski in version: 9.3.73-0 🚀
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No help site changes required. This PR is a pure internal performance optimization (consolidating regex passes in |
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🚀 Deployed to production by https://github.com/Beamanator in version: 9.3.73-4 🚀
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Explanation of Change
Reduces the number of sequential string traversals in
RenderHTML'suseMemofrom 6 down to 3, and eliminates 4 inline regex literals that were being recompiled on every call.What changed:
&#91;→[,&#93;→]): 2 literalreplaceAllcalls merged into 1 regex pass usingRE_BRACKET_ESCAPE = /&#9[13];/greplaceAllcalls merged into 1 combined alternation patternRE_EMOJI_OPEN_OR_CLOSE<br>cleanup inside<ul>: 2 separate regexreplaceAllcalls merged into 1 combined alternation patternRE_BR_CLEANUPBenchmark (109 KB synthetic HTML payload, 5000 iterations):
Correctness verified: both approaches produce byte-identical output on a payload containing all three replacement cases.
To ground this in user experience - let's say the user has 200 messages loaded. ~0.08ms per message isn't much, but across 200 messages that's ~16ms, which is the maximum amount of time you can spend per frame to keep 60fps. If messages re-render multiple times, then the speedup has higher amortized value.
Fixed Issues
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Tests
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[and]characters — verify brackets render correctly- item) — verify no extra blank bullets appearOffline tests
N/A — this is a pure string-processing optimisation with no network interaction.
QA Steps [No QA]
Same as Tests above.
PR Author Checklist
### Fixed Issuessection aboveTestssectionOffline stepssectionQA stepssectioncanBeMissingparam foruseOnyxtoggleReportand notonIconClick)src/languages/*files and using the translation methodSTYLE.md) were followedAvatar, I verified the components usingAvatarare working as expected)StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))npm run compress-svg)Avataris modified, I verified thatAvataris working as expected in all cases)Designlabel and/or tagged@Expensify/designso the design team can review the changes.ScrollViewcomponent to make it scrollable when more elements are added to the page.mainbranch was merged into this PR after a review, I tested again and verified the outcome was still expected according to theTeststeps.Screenshots/Videos
Android: Native
Android: mWeb Chrome
iOS: Native
iOS: mWeb Safari
MacOS: Chrome / Safari
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