Fix LHN flickers and scroll position restoring #55486

rezkiy37 · 2025-01-20T17:31:49Z

Explanation of Change

The PR enhances LHN (FlashList) performance. Especially when the user switches between tabs. It allows FlashList to avoid auto-measuring by setting the static estimated list size.

Fixed Issues

$ #53605
PROPOSAL: #53605 (comment)

Tests

Verify that no errors appear in the JS console

Scroll LHN down.
Tap on the "Search" tab.
Tap on the "Inbox" tab.
Verify that LHN does not flicker when rendering rows.
Verify that LHN always scrolls on the correct previous position.

Offline tests

Same as "Tests".

QA Steps

// TODO: These must be filled out, or the issue title must include "[No QA]."

Verify that no errors appear in the JS console

Same as "Tests".

PR Author Checklist

Screenshots/Videos

Android: Native

Android.mp4

Android: mWeb Chrome

Android.Chrome.mp4

iOS: Native

IOS.mp4

iOS: mWeb Safari

IOS.Safari.mp4

MacOS: Chrome / Safari

Chrome.mp4

MacOS: Desktop

Desktop.mp4

…/53605-lhn-flickers

hungvu193 · 2025-01-23T09:48:23Z

@rezkiy37 It looks pretty cool so far. Can you resolve the linting and mark this as ready for review?

rezkiy37 · 2025-01-23T10:00:34Z

@hungvu193, hi!
Yes, of course. Can we assume that the proposal has been approved?

hungvu193 · 2025-01-23T10:01:34Z

@hungvu193, hi! Yes, of course. Can we assume that the proposal has been approved?

Yes. You got assigned to the issue already. Please go ahead 😄

…/53605-lhn-flickers

melvin-bot · 2025-01-23T17:55:47Z

@hungvu193 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]

rezkiy37 · 2025-01-23T17:58:17Z

Local tests have passed well.

hungvu193 · 2025-01-24T03:15:45Z

@rezkiy37 on mWeb Chrome, there's an empty view display for a while before LHN displays. It looks like it display the first index of LHN first then scroll to the current position.

Screen.Recording.2025-01-24.at.10.10.42.mov

hungvu193 · 2025-01-24T03:31:46Z

It happens also on Desktop and Chrome

Screen.Recording.2025-01-24.at.10.29.45.mov

…/53605-lhn-flickers

rezkiy37 · 2025-01-24T16:26:33Z

@hungvu193, I am thinking about the next fix for web-based platforms. The app uses the scrollToOffset method anyway

App/src/components/LHNOptionsList/LHNOptionsList.tsx

Line 256 in 264728f

flashListRef.current.scrollToOffset({offset});

What if apply animated: true? It really smoothly scrolls to the previous position. When the list is extremely long it can take time to render items. However, it does not flicker. Yeah, there is a blank area but I don't think it is critical.

Moreover, the current behavior does not restore the position at all. So the user has to do it manually.

Video

Example.mp4

WDYT?

hungvu193 · 2025-01-25T17:29:25Z

It looks weird to me 😄. I think that's fine to keep current behavior on web (stay at top) if we can't fix the empty issue.

Screen.Recording.2025-01-26.at.00.28.01.mov

rezkiy37 · 2025-01-27T09:40:19Z

@hungvu193, well. I will apply the current changes for native platforms only for now. Also, I can work on a follow-up to find a web solution.

hungvu193 · 2025-01-27T09:55:14Z

@hungvu193, well. I will apply the current changes for native platforms only for now. Also, I can work on a follow-up to find a web solution.

Thank you 😁

…/53605-lhn-flickers

rezkiy37 · 2025-01-27T16:56:32Z

@hungvu193, done 🙂

Video

Web.mp4

IOS.mp4

hungvu193 · 2025-01-28T05:20:27Z

Ty. Look good to me. I'll complete the checklist today 🤞

hungvu193

Reviewer Checklist

I have verified the author checklist is complete (all boxes are checked off).
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I checked that screenshots or videos are included for tests on all platforms
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I verified tests pass on all platforms & I tested again on:
- Android: Native
- Android: mWeb Chrome
- iOS: Native
- iOS: mWeb Safari
- MacOS: Chrome / Safari
- MacOS: Desktop
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If any new file was added I verified that:
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Screenshots/Videos

Android: Native

Android.mov

Android: mWeb Chrome

Screen.Recording.2025-01-24.at.10.10.42.mov

iOS: Native

ios.mov

iOS: mWeb Safari

mSafari.mov

MacOS: Chrome / Safari

Screen.Recording.2025-01-24.at.10.29.45.mov

MacOS: Desktop

Screen.Recording.2025-01-24.at.10.29.45.mov

melvin-bot · 2025-01-28T09:08:40Z

We did not find an internal engineer to review this PR, trying to assign a random engineer to #53605 as well as to this PR... Please reach out for help on Slack if no one gets assigned!

…/53605-lhn-flickers

rezkiy37 · 2025-01-28T09:37:44Z

I've synced it up.

puneetlath · 2025-01-28T20:54:53Z

src/hooks/useEstimatedListSize/index.native.ts

+import variables from '@styles/variables';
+import type UseEstimatedListSize from './types';
+
+const useEstimatedListSize: UseEstimatedListSize = () => {


What list is this referring to? The LHN? Or any list?

Also, can we add some comments explaining what this is and when one might use it.

The LHN. Working on it.

Done - 717c184, 88f6bda.

puneetlath · 2025-01-28T20:55:22Z

Also, are there any tests we can add related to this change?

…/53605-lhn-flickers

…edListSize hook

rezkiy37 · 2025-01-29T09:54:17Z

Also, are there any tests we can add related to this change?

No, I don't think so.

…/53605-lhn-flickers

rezkiy37 · 2025-01-30T11:19:59Z

I've run the perf-test locally and it passed successfully.

puneetlath · 2025-01-30T20:08:29Z

I've run the Reassure test 3 times and it has failed every time. Can you look into it further @rezkiy37

rezkiy37 · 2025-01-31T09:39:27Z

I've run the Reassure test 3 times and it has failed every time. Can you look into it further @rezkiy37

Yes, I can, However, I already have mentioned that it works properly for me locally. I will take a look one more time.

…/53605-lhn-flickers

… tests

rezkiy37 · 2025-01-31T12:33:36Z

@puneetlath, I just needed to mock the newly added hook in the test file. It works properly now. The tests have been passed. It is ready to merge 🙂

github-actions · 2025-02-03T23:33:42Z

🚀 Deployed to staging by https://github.com/puneetlath in version: 9.0.94-0 🚀

platform	result
🤖 android 🤖	success ✅
🖥 desktop 🖥	success ✅
🍎 iOS 🍎	success ✅
🕸 web 🕸	success ✅
🤖🔄 android HybridApp 🤖🔄	success ✅
🍎🔄 iOS HybridApp 🍎🔄	success ✅

IuliiaHerets · 2025-02-04T11:15:21Z

This PR is failing because of issue #56323

rezkiy37 · 2025-02-04T13:19:42Z

@IuliiaHerets, this PR is not failing on the web because it fixes only native platforms.

IuliiaHerets · 2025-02-04T17:22:37Z

@rezkiy37 Ok, thanks for letting me know

rezkiy37 added 2 commits January 20, 2025 18:30

Add window dimensions to LHNOptionsList for dynamic list sizing

58fc9c9

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

7bf55d1

…/53605-lhn-flickers

rezkiy37 added 4 commits January 23, 2025 17:46

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

2d48c07

…/53605-lhn-flickers

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

c6cad82

…/53605-lhn-flickers

Use named imports LHNOptionsList

4d6dfea

Do not default string IDs LHNOptionsList

e7bd150

rezkiy37 changed the title ~~[WIP] Fix LHN flickers and scroll position restoring~~ Fix LHN flickers and scroll position restoring Jan 23, 2025

rezkiy37 marked this pull request as ready for review January 23, 2025 17:55

rezkiy37 requested a review from a team as a code owner January 23, 2025 17:55

melvin-bot bot requested review from hungvu193 and removed request for a team January 23, 2025 17:55

rerun tests

838ee69

rezkiy37 mentioned this pull request Jan 23, 2025

[$250] Android - LHN flickers when scrolled down and switching between Search and Inbox #53605

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Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

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…/53605-lhn-flickers

rezkiy37 added 3 commits January 27, 2025 17:38

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

1acb9ad

…/53605-lhn-flickers

create useEstimatedListSize

fd4ea52

use useEstimatedListSize

45220f2

hungvu193 approved these changes Jan 28, 2025

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rezkiy37 added 3 commits January 29, 2025 10:26

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

9853e57

…/53605-lhn-flickers

Rename and refactor estimated list size hook for LHN usage

717c184

Add documentation for native and web implementations of useLHNEstimat…

88f6bda

…edListSize hook

rezkiy37 requested a review from puneetlath January 29, 2025 09:54

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

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rezkiy37 added 3 commits January 31, 2025 10:40

Merge branch 'main' of https://github.com/rezkiy37/Expensify into fix…

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…/53605-lhn-flickers

retest

6f2c91e

Add mock for useLHNEstimatedListSize hook in SidebarLinks performance…

8576b7e

… tests

rezkiy37 dismissed puneetlath’s stale review via 8576b7e January 31, 2025 12:19

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puneetlath merged commit 7b48dcf into Expensify:main Jan 31, 2025
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Deploy Checklist: New Expensify 2025-02-03 #56280

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IuliiaHerets mentioned this pull request Feb 4, 2025

LHN - LHN scrolls to the top when navigating between tabs #56323

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Fix LHN flickers and scroll position restoring #55486

Fix LHN flickers and scroll position restoring #55486

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Fix LHN flickers and scroll position restoring #55486

Fix LHN flickers and scroll position restoring #55486

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Explanation of Change

Fixed Issues

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