perf: move screen focus to LHNOptionsList to avoid re-renders by OlimpiaZurek · Pull Request #62968 · Expensify/App

OlimpiaZurek · 2025-05-28T15:32:39Z

Explanation of Change

Problem

OptionRowLHN use theuseFocusEffect hook locally inside each row component. This means that every time the screen focus changed (e.g., navigating between Inbox → Reports), all instances of OptionRowLHN triggered re-renders — even if nothing else changed.
In large lists (e.g., LHN with hundreds/thousands of rows), this caused significant performance hits and longer render durations.

Solution

Move the screen focus logic to the parent component (LHNOptionsList) and passed isScreenFocused value as a prop to each OptionRowLHN instead of using useFocusEffect within the row. Replace the custom focus hook with React Navigation’s built-in useIsFocused() in the parent for better clarity and simplicity. This avoided each row setting up its own focus listener and prevented cascading re-renders on screen transitions. This change preserves the required focus-based behavior while minimizing redundant work across many list items.

Performance gain

Android
Commit count dropped from 17 → 14, total render time down by ~29% ( from8941ms down to 6328ms -> Total Duration Difference: 2613.470 ms)
iOS - Commit count dropped from 25 → 22, total render time down by ~14% ( from 3297ms down to 2820ms -> Total Duration Difference: -477.069 ms)

Before:

After:

Fixed Issues

$ #60007
PROPOSAL:

Tests

This change is performance-related only — no functionality is expected to change. The goal is to avoid unnecessary re-renders in long LHN lists by lifting useFocusEffect `out of each row and managing focus state at the parent level.
Please check that there are no regressions in the behavior tied to screen focus

Verify that no errors appear in the JS console

Offline 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

PR Author Checklist

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

MacOS: Desktop

kacper-mikolajczak

Fantastic, LGTM!! Thank you for working on this - the perf results look promising❤️

One idea that popped in my head while looking at the changes, we might as an alternative use context instead of props drilling. It would simplify the types (no need to distinguish between isOptionFocused and isScreenFocused because it stays the same).

When looking at it further, it'd be nice for ScreenWrapper to expose that functionality, but that's story for different ticket :) Thanks once again!

kacper-mikolajczak · 2025-05-29T07:11:55Z

src/hooks/useIsScreenFocus.ts

+import {useFocusEffect} from '@react-navigation/native';
+import {useCallback, useState} from 'react';
+
+export default function useIsScreenFocusedRef() {


Tiny typo useIsScreenFocusedRef -> useIsScreenFocused

Would it be fine for our use-case (as we are using just state) to go with useIsFocus instead and avoid custom hook altogether?

Good point. Replaced custom hook with useIsFocused as it has the same behavior but simplifies the code

OlimpiaZurek · 2025-05-29T09:10:46Z

Fantastic, LGTM!! Thank you for working on this - the perf results look promising❤️

One idea that popped in my head while looking at the changes, we might as an alternative use context instead of props drilling. It would simplify the types (no need to distinguish between isOptionFocused and isScreenFocused because it stays the same).

When looking at it further, it'd be nice for ScreenWrapper to expose that functionality, but that's story for different ticket :) Thanks once again!

@kacper-mikolajczak Thank you for the feedback ❤️ .

Agree — using context could help avoid the prop drilling and clean up the types a bit. The main reason I went with props here was to keep things a bit more explicit and avoid introducing extra renders that might come from context updates (especially in big lists like LHN).

melvin-bot · 2025-05-29T11:36:57Z

@rushatgabhane 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]

github-actions · 2025-05-29T14:51:08Z

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

github-actions · 2025-05-29T15:24:04Z

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rushatgabhane · 2025-05-29T17:54:59Z

Reviewer Checklist

I have verified the author checklist is complete (all boxes are checked off).
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Screenshots/Videos

Android: HybridApp

WhatsApp.Video.2025-05-29.at.21.48.15.mp4

Android: mWeb Chrome

iOS: HybridApp

Screen.Recording.2025-05-30.at.13.00.31.mov

iOS: mWeb Safari

Screen.Recording.2025-05-30.at.13.06.15.mov

MacOS: Chrome / Safari

Screen.Recording.2025-05-30.at.05.10.30.mov

MacOS: Desktop

rushatgabhane

LGTM

mountiny

Really nice improvement, great job!

OSBotify · 2025-05-30T14:23:01Z

✋ This PR was not deployed to staging yet because QA is ongoing. It will be automatically deployed to staging after the next production release.

github-actions · 2025-06-02T19:57:16Z

🚀 Deployed to staging by https://github.com/mountiny in version: 9.1.55-0 🚀

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

IuliiaHerets · 2025-06-02T21:14:01Z

@OlimpiaZurek Do we have QA steps for this?

OlimpiaZurek · 2025-06-03T07:50:39Z

@IuliiaHerets

In this PR, we moved the focus logic to the parent to avoid unnecessary re-renders, so these QA steps are just to make sure nothing broke with focus-related behavior after the performance tweak:

Tooltip Behavior:

Create a new account and start a few chats.
Verify that a tooltip (e.g., “Get Started Here”) is shown on one of the reports in the LHN.

Context menu:

Long-press (on mobile) or right-click (on desktop/web) a chat in the LHN.
Verify that the context menu appears correctly with the expected options.

github-actions · 2025-06-03T12:52:07Z

🚀 Deployed to staging by https://github.com/mountiny in version: 9.1.56-2 🚀

platform	result
🖥 desktop 🖥	success ✅
🕸 web 🕸	success ✅
🤖 android 🤖	failure ❌
🍎 iOS 🍎	success ✅

IuliiaHerets · 2025-06-03T14:49:34Z

@OlimpiaZurek Get started tooltip was removed here. Or was it revert again?
QA team sees only the tooltip about GBR and RBR on Concierge chat.

Get.mp4

OlimpiaZurek · 2025-06-03T15:12:28Z

Based on the code, it shows one of 3 different tooltips depending on specific conditions, so it’s hard to say if the behavior was recently changed or reverted. In this PR, I didn’t touch the tooltip logic—so the only thing that needs to be checked is whether the tooltip still shows up correctly, just to make sure nothing broke as a side effect of the refactor.

IuliiaHerets · 2025-06-03T17:04:40Z

@OlimpiaZurek

so the only thing that needs to be checked is whether the tooltip still shows up correctly

Which tooltip do you mean?
Can you add clear steps to the QA Steps to check this correctly?

github-actions · 2025-06-03T20:04:32Z

🚀 Deployed to staging by https://github.com/mountiny in version: 9.1.58-0 🚀

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

roryabraham · 2025-06-03T23:14:55Z

confirmed that this caused a regression, so going to revert

roryabraham · 2025-06-03T23:15:56Z

Maybe when we redo it we can try to add an automated UI test that covers the regression? Not sure whether gestures like long-press are testable, but if they are it seems like it would be a good test

mountiny · 2025-06-04T13:00:18Z

Thanks for the revert

github-actions · 2025-06-04T16:20:46Z

🚀 Deployed to production by https://github.com/roryabraham in version: 9.1.58-4 🚀

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

perf: move screen focus to LHNOptionsList to avoid re-renders

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kacper-mikolajczak approved these changes May 29, 2025

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fix typo

f41dcff

add useIsFocused instead of custom hook

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OlimpiaZurek marked this pull request as ready for review May 29, 2025 11:36

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[Due for payment 2025-07-14] [CRITICAL] Improve the perfromance of bottom tabs switching #60007

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mountiny approved these changes May 30, 2025

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mountiny merged commit bf272cb into Expensify:main May 30, 2025
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Deploy Checklist: New Expensify 2025-06-02 #63263

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[Due for payment 2025-06-12] [Due for payment 2025-06-11] Inbox - Long-press menu not showing after entering and returning from a chat #63396

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roryabraham mentioned this pull request Jun 3, 2025

Revert "perf: move screen focus to LHNOptionsList to avoid re-renders" #63403

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