perf: Migrate to Flashlist in MoneyRequestReportTransactionList by TMisiukiewicz · Pull Request #91422 · Expensify/App

TMisiukiewicz · 2026-05-22T11:58:02Z

Explanation of Change

Problem
On heavy money-request reports the RHP list was effectively non-virtualised. The inner transactions section was rendered via plain .map() inside the parent FlatList's ListHeaderComponent, which renders eagerly. Every transaction row mounted synchronously when the report opened, pushing report open time to ~20–30s for a report with 1600 expenses and producing a noticeable jank window on every navigation.

Solution

Unified list — merged the inner transactions section and the outer report-actions section into a single virtualised list. A discriminated-union UnifiedListItem (section-header | transaction | transactions-footer | report-action) flows through one renderItem dispatcher, so transactions and chat messages now share the same recycler window instead of one being eagerly rendered inside the other's header.
FlashList — migrated the list from react-native's FlatList (FlatListWithScrollKey). initialScrollIndex replaces the FlatList-specific useFlatListScrollKey wrapper
Controller + sub-component — MoneyRequestReportTransactionList continues to own the transaction-domain state (sort, group-by, selection, columns, totals, etc.) and exposes it to the parent via a render-prop controller. The parent renders a small MoneyRequestReportUnifiedList sub-component that assembles the FlashList from controller data plus the report-actions list

Fixed Issues

$ #91425
PROPOSAL:

Tests

Go to Spend tab
Go to Reports tab
Open Report with a couple of expenses - where list is not scrollable
Verify everything is displayed correctly
Open Report with a lot of expenses in multiple categories
Verify report opens correctly
Select a single report and verify it selects correctly
Select all reports from a category using category header and verify they are all selected (even if they are out of the viewport)
Select all reports from all categories using top table header and verify all reports in a list get selected
Send a message on the report and verify you are scrolled to the bottom of the list
Web only: Narrow down the viewport horizontally and verify the table is scrollable horizontally

Verify that no errors appear in the JS console

Offline tests

N/A

QA Steps

Same as tests

Verify that no errors appear in the JS console

PR Author Checklist

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

ios.mov

iOS: mWeb Safari

MacOS: Chrome / Safari

web.mov

…rt-list

…ation

codecov · 2026-05-22T12:13:37Z

Codecov Report

✅ Changes either increased or maintained existing code coverage, great job!

Files with missing lines	Coverage Δ
src/CONST/index.ts	`93.84% <ø> (ø)`
src/components/Table/TableBody.tsx	`96.00% <100.00%> (ø)`
...ansactionItemRow/DeferredTransactionItemRowRBR.tsx	`100.00% <100.00%> (ø)`
...ents/TransactionItemRow/TransactionItemRowWide.tsx	`96.26% <100.00%> (+0.03%)`	⬆️
src/components/TransactionItemRow/index.tsx	`83.58% <100.00%> (+0.50%)`	⬆️
src/hooks/useReportActionsScroll.ts	`97.89% <100.00%> (ø)`
src/hooks/useScrollToEndOnNewMessageReceived.ts	`94.11% <100.00%> (ø)`
...stReportView/MoneyRequestReportTransactionItem.tsx	`0.00% <0.00%> (ø)`
...ts/TransactionItemRow/TransactionItemRowNarrow.tsx	`0.00% <0.00%> (ø)`
...ew/MoneyRequestReportTransactionLongPressModal.tsx	`0.00% <0.00%> (ø)`
... and 4 more
... and 17 files with indirect coverage changes

…onents

…rt-list

melvin-bot · 2026-05-26T07:20:10Z

@aimane-chnaif Please copy/paste the Reviewer Checklist from here into a new comment on this PR and complete it. If you have the K2 extension, you can simply click: [this button]

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mountiny · 2026-06-10T13:20:46Z

@aimane-chnaif kind bump

…asts The unified list ref was bridged from the shared ActionList context's FlatList-typed slot to the FlashList via `as unknown as` casts, tripping the no-unsafe-type-assertion seatbelt (3 > 1 allowed). Mirror the InvertedFlashList pattern: type the ref prop as FlatListRefType and forward it through @components/FlashList as a spread prop, so no cast is needed at the call site. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

The type's only external consumers were the ref-cast imports in MoneyRequestReportActionsList and MoneyRequestReportTransactionList, both removed in the previous commit. It is still used internally, so keep the type and drop only the export. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

aimane-chnaif · 2026-06-10T14:26:43Z

When we have task report action in the middle, there's issue.
Production is also not working well but the behavior is different.

And the content is not rendered immediately.

production.mp4

this.branch.mp4

adhorodyski · 2026-06-15T08:38:21Z

Updating the PR now and I'll look into this issue.

…-list # Conflicts: # src/components/MoneyRequestReportView/MoneyRequestReportActionsList.tsx # src/components/MoneyRequestReportView/MoneyRequestReportTransactionList.tsx # src/components/TransactionItemRow/index.tsx

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

adhorodyski · 2026-06-15T13:16:08Z

@aimane-chnaif

When we have task report action in the middle, there's issue.
Production is also not working well but the behavior is different.
And the content is not rendered immediately.

This looks broken in both scenarios but I cannot reproduce this case locally yet. It's potentially recycling working on report-action only (not type-keyed).

…-list

aimane-chnaif · 2026-06-15T14:18:00Z

Please create 40+ expenses (easy to create using duplicate expense feature) to build long list.
And after task created (assign yourself as assignee), send many messages so the task report action is in the middle

TMisiukiewicz · 2026-06-16T10:29:12Z

Merged latest main and couldn't reproduce. @aimane-chnaif could you check again? Maybe it just resolved after resolving conflicts

Simulator.Screen.Recording.-.iPhone.17.Pro.-.2026-06-16.at.12.28.48.mov

mountiny · 2026-06-16T13:20:37Z

@aimane-chnaif please let us know in Slack

aimane-chnaif · 2026-06-16T13:30:55Z

Can you please run new build?

github-actions · 2026-06-16T21:00:32Z

🚧 @mountiny has triggered a test Expensify/App build. You can view the workflow run here.

mountiny · 2026-06-19T13:59:11Z

@aimane-chnaif Making freshest build

github-actions · 2026-06-19T14:00:21Z

🚧 @mountiny has triggered a test Expensify/App build. You can view the workflow run here.

github-actions · 2026-06-19T14:05:48Z

🧪🧪 Use the links below to test this adhoc build on Android, iOS, and Web. Happy testing! 🧪🧪
Built from App PR #91422.

Android 🤖	iOS 🍎
https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-android-Adhoc-6a58ae00066-912d4a2-827eb595a8b0c4d019ce3c627c45f2a8b67ff252/index.html	https://ad-hoc-expensify-cash.s3.us-east-1.amazonaws.com/rock-artifacts/ad-hoc/rock-ios-device-AdHoc-6a58ae0-912d4a2-3c48ff41d76822c5ad4cf17826e66136f0777d29/index.html

Web 🕸️
https://91422.pr-testing.expensify.com

👀 View the workflow run that generated this build 👀

aimane-chnaif · 2026-06-19T14:12:15Z

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Screenshots/Videos

Android: HybridApp

Android: mWeb Chrome

iOS: HybridApp

iOS: mWeb Safari

MacOS: Chrome / Safari

mountiny · 2026-06-22T18:40:54Z

@aimane-chnaif can you prioritize this please?

@TMisiukiewicz @adhorodyski conflicts

…rt-list # Conflicts: # src/components/MoneyRequestReportView/MoneyRequestReportActionsList.tsx

TMisiukiewicz · 2026-06-23T07:20:35Z

@mountiny resolved conflicts

aimane-chnaif · 2026-06-23T08:17:23Z

job 2 failing but seems not related

aimane-chnaif · 2026-06-23T08:41:47Z

Hopefully no conflict but let's wait until #93403 is deployed and then retest since it refactored FlashList scrolling behavior.

…rt-list # Conflicts: # src/CONST/index.ts

TMisiukiewicz · 2026-06-24T06:46:41Z

updated with latest main, @mountiny can you run a fresh adhoc?

melvin-bot Bot assigned TMisiukiewicz May 22, 2026

TMisiukiewicz added 3 commits May 22, 2026 14:00

Merge remote-tracking branch 'origin/main' into perf/virtualised-repo…

4b12b1a

…rt-list

perf: migrate transaction list from .map() to FlashList for virtualiz…

4551621

…ation

perf: unify transactions + actions into one virtualised list

f68b1ee

fix: restore lastTransactionID and isDesktopTableLayout

d64ff24

mountiny mentioned this pull request May 22, 2026

perf: virtualise transaction list in report screen #91425

Open

TMisiukiewicz added 8 commits May 25, 2026 09:14

fix: CI spellcheck and remove memoization wrappers

f4fbe38

fix: rephrase virtualized comment to satisfy cspell

1ee223b

use Flashlist

52ceec0

refactor: extract unified list render-prop body into sub-component

2779f70

fix: hoist long-press modal out of virtualised footer cell

71af131

Merge branch 'main' into perf/virtualised-report-list

81bb0f0

refactor: extract long-press modal and horizontal scroll wrapper comp…

1220e39

…onents

Merge remote-tracking branch 'origin/main' into perf/virtualised-repo…

6b5c9be

…rt-list

TMisiukiewicz changed the title ~~perf: virtualise transaction list in report screen~~ perf: Migrate to Flashlist in MoneyRequestReportTransactionList May 26, 2026

TMisiukiewicz marked this pull request as ready for review May 26, 2026 07:20

TMisiukiewicz requested review from a team as code owners May 26, 2026 07:20

melvin-bot Bot requested review from aimane-chnaif and joekaufmanexpensify and removed request for a team and joekaufmanexpensify May 26, 2026 07:20

github-actions Bot reviewed May 26, 2026

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Comment thread src/components/MoneyRequestReportView/MoneyRequestReportTransactionList.tsx Outdated

github-actions Bot reviewed May 26, 2026

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Comment thread src/components/MoneyRequestReportView/MoneyRequestReportActionsList.tsx Outdated

chatgpt-codex-connector Bot reviewed May 26, 2026

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Comment thread src/components/MoneyRequestReportView/MoneyRequestReportActionsList.tsx Outdated

TMisiukiewicz added 2 commits May 26, 2026 11:37

remove dead keyExtractor from transaction list controller

143946e

fix unread marker index offset when transactions are present

03ce297

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Merge branch 'Expensify:main' into perf/virtualised-report-list

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adhorodyski and others added 2 commits June 10, 2026 15:29

adhorodyski and others added 2 commits June 15, 2026 10:50

Remove unused eslint-disable directive for jsx-props-no-spreading

22ca09a

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Merge remote-tracking branch 'exfy/main' into perf/virtualised-report…

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…-list

Merge ck/main into perf/virtualised-report-list

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Merge branch 'Expensify:main' into perf/virtualised-report-list

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Merge remote-tracking branch 'origin/main' into perf/virtualised-repo…

b6f91e1

…rt-list # Conflicts: # src/components/MoneyRequestReportView/MoneyRequestReportActionsList.tsx

Merge remote-tracking branch 'origin/main' into perf/virtualised-repo…

80de6da

…rt-list # Conflicts: # src/CONST/index.ts

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