Expenses list performance

[perunt]

It's not a complete fix, but just another enhancement that lets you see better performance in the Expenses list.

Explanation of Change

Fixed Issues

$ #55562
PROPOSAL:

Tests

• Verify that no errors appear in the JS console

Offline tests

QA Steps

1. Open the app
2. Navigate to Report search > Expenses
3. Scroll up and down through the list.
4. Try to switch bottom tabs few times.
5. Again go to report search > Expenses
6. Scroll up and down through the list.
7. See the freezes (and drop in frame rates when scrolling the App)
8. If you don't see the freezes yet, do step 4, and try again.

Test the multiselect feature

// 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

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
  • MacOS: Desktop
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
• I followed proper code patterns (see Reviewing the code)
  • I verified that any callback methods that were added or modified are named for what the method does and never what callback they handle (i.e. toggleReport and not onIconClick)
  • I verified that comments were added to code that is not self explanatory
  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
  • I verified any copy / text shown in the product is localized by adding it to src/languages/* files and using the translation method
    • If any non-english text was added/modified, I used JaimeGPT to get English > Spanish translation. I then posted it in #expensify-open-source and it was approved by an internal Expensify engineer. Link to Slack message:
  • I verified all numbers, amounts, dates and phone numbers shown in the product are using the localization methods
  • I verified any copy / text that was added to the app is grammatically correct in English. It adheres to proper capitalization guidelines (note: only the first word of header/labels should be capitalized), and is either coming verbatim from figma or has been approved by marketing (in order to get marketing approval, ask the Bug Zero team member to add the Waiting for copy label to the issue)
  • I verified proper file naming conventions were followed for any new files or renamed files. All non-platform specific files are named after what they export and are not named "index.js". All platform-specific files are named for the platform the code supports as outlined in the README.
  • I verified the JSDocs style guidelines (in STYLE.md) were followed
• If a new code pattern is added I verified it was agreed to be used by multiple Expensify engineers
• I followed the guidelines as stated in the Review Guidelines
• I tested other components that can be impacted by my changes (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar are working as expected)
• I verified all code is DRY (the PR doesn't include any logic written more than once, with the exception of tests)
• I verified any variables that can be defined as constants (ie. in CONST.ts or at the top of the file that uses the constant) are defined as such
• I verified that if a function's arguments changed that all usages have also been updated correctly
• If any new file was added I verified that:
  • The file has a description of what it does and/or why is needed at the top of the file if the code is not self explanatory
• If a new CSS style is added I verified that:
  • A similar style doesn't already exist
  • The style can't be created with an existing StyleUtils function (i.e. StyleUtils.getBackgroundAndBorderStyle(theme.componentBG))
• If the PR modifies code that runs when editing or sending messages, I tested and verified there is no unexpected behavior for all supported markdown - URLs, single line code, code blocks, quotes, headings, bold, strikethrough, and italic.
• If the PR modifies a generic component, I tested and verified that those changes do not break usages of that component in the rest of the App (i.e. if a shared library or component like Avatar is modified, I verified that Avatar is working as expected in all cases)
• If the PR modifies a component related to any of the existing Storybook stories, I tested and verified all stories for that component are still working as expected.
• If the PR modifies a component or page that can be accessed by a direct deeplink, I verified that the code functions as expected when the deeplink is used - from a logged in and logged out account.
• If the PR modifies the UI (e.g. new buttons, new UI components, changing the padding/spacing/sizing, moving components, etc) or modifies the form input styles:
  • I verified that all the inputs inside a form are aligned with each other.
  • I added Design label and/or tagged @Expensify/design so the design team can review the changes.
• If a new page is added, I verified it's using the ScrollView component to make it scrollable when more elements are added to the page.
• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

MacOS: Desktop

[melvin-bot]

@shubham1206agra 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]

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

[shubham1206agra]

@perunt The frames look super choppy on expense list when scrolling up and down.

[hannojg]

Okay, I fixed the failing of three of the reassure tests.
One test is still failing though:

➡️  Count changes
 - [SelectionList] should scroll and select a few items [render]: 0.0 ms → 0.0 ms  | 12 → 13 (+1, +8.3%) 🔴

However, this is expected. Before the test was setup wrong. The contentSize for the scroll even is the total size of the list with all items. We render thousands of items so the contentSize should be pretty long. However, it was set to a size of 10 items. This way the VirtualizedList (which is backing SectionList) was internally re-rendering less often as its logic acted like its already done rendering all possible items.

We fixed the test for correctness, set the correct contentSize and thus we have an additional re-render.

If we run the tests with the changes of this PR but use the faulty values we can see that we actually have less renders (which is what this PR aims to achieve):

So its actually fine merging this PR with the one failing reassure test!

Ready for review

[github-actions]

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

[github-actions]

🧪🧪 Use the links below to test this adhoc build on Android, iOS, Desktop, and Web. Happy testing! 🧪🧪

Android 🤖	iOS 🍎
https://ad-hoc-expensify-cash.s3.amazonaws.com/android/56884/index.html	https://ad-hoc-expensify-cash.s3.amazonaws.com/ios/56884/index.html
Desktop 💻	Web 🕸️
https://ad-hoc-expensify-cash.s3.amazonaws.com/desktop/56884/NewExpensify.dmg	https://56884.pr-testing.expensify.com

---

👀 View the workflow run that generated this build 👀

[shubham1206agra]

@hannojg Sorry, but the performance is still laggy. Can you check why is it this laggy?

[hannojg]

Sure!
I think this PR wasn't intended as a full fix, but as a first effort

It's not a complete fix, but just another enhancement that lets you see better performance in the Expenses list.

I can try to fix the performance in this PR, or we go ahead with this one as it slightly improves performance, and then a follow up PR that fixes the problem entirely (so maybe that would be easier for review?)

[shubham1206agra]

@hannojg The problem is performance looks more laggy than it was on start of the PR.

[hannojg]

Alright, thanks for the info, we will double check!

[perunt]

I'm measuring the difference to analyze the numbers since I’m noticing a boost, and it can be hard to judge by eye. I’ll provide you with the numbers soon. Also, tomorrow morning I’ll be able to test it on a super low-end device to confirm the result

[perunt]

I tested scrolling performance under the same conditions:

• 45 regular downward swipes with a 0.3s delay between each. (The first two were intentionally slower to check animation smoothness, while the rest followed a steady rhythm)
• 17 rapid upward swipes to quickly return to the top
• 20 rapid downward swipes for additional stress testing

Comparing both implementations side by side, I noticed a significant reduction in whitespace compared to the main branch. That said, there’s still room for improvement. As I mentioned earlier, this is just the first step in optimizing performance for Expenses - not the final version.

The attached screen recording shows the entire test, making it easy to compare both versions

Old Implementation

Old_r_480.mov

New Implementation

New_r_480.mov

@shubham1206agra what method are you using to compare the old and new implementations? Could you share some details on where exactly it performs worse? Is it related to scroll smoothness, whitespace, or jumping issues? Thanks in advance!

[shawnborton]

What's the latest on this one? it's been stale for a few weeks now.

[perunt]

What's the latest on this one? it's been stale for a few weeks now.

This PR was on hold because the screen was being migrated to a different list component (SectionList was replaced with FlashList)
Next, I’ll measure the performance gains from this PR and also check how much of a boost FlashList (or other lists) actually gives

[perunt]

Closing in favor of #61185