feat: Reduce amount of items displayed per page of SelectionList

[MrMuzyk]

Explanation of Change

Changed CONST that was used in BaseSelectionList to indicate how many items we should initially render. Decreased it to 50 to make it more in-line with usual amount of items displayed per page of paginated content.

I've also fixed a case where user loaded more items on the list and selected one of the items that wasn't initially loaded. Previously it was resetting the set page.

Fixed Issues

$ #65634
PROPOSAL:

Tests

Same as QA steps

• Verify that no errors appear in the JS console

Offline tests

QA Steps

Note:
All of the selection lists in the project will now initially load 50 items instead of 500. Most notable cases are long list that are in the app, ie: selecting users in filters or Tags list. Verifying that one of the lists works correctly should give us confidence that the remaining lists work without any issues as well.

Precondition: Be on account that has many reports from 100+ different users

• Go to reports page
• Click on From filter
• List should now load initially 50 items and after scrolling to the end of it user should get Show more button allowing him to load more items
• Scroll the list and click on Show more button
• Select freshly loaded items
• Options should remain in place and displayed page shouldn't reset
• 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)
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• I followed proper code patterns (see Reviewing the code)
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• 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)
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Screenshots/Videos

Android: Native

android.native.mov

Android: mWeb Chrome

android.web.mov

iOS: Native

ios.native.mov

iOS: mWeb Safari

ios.web.mov

MacOS: Chrome / Safari

web.mov

MacOS: Desktop

desktop.mov

[melvin-bot]

@jayeshmangwani 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]

[MrMuzyk]

When recording test evidence I've noticed an issue that became more apparent after decreasing the amount of initially rendered items to 50. Whenever a user was selecting an item past the initial threshold currently displayed page was getting reset. This is also currently a problem on main that was happening regardless of the set amount of items to render.

I've updated a PR with a fix for that as well. Changing the CONST to 50 made this issue popup more frequently now so I've decided to fix it here. Hope it's not a problem 😅

[jayeshmangwani]

@MrMuzyk @mountiny , just confirming - after this PR, we're now displaying 50 tags, whereas on staging currently shows 500 on the first render(initially). Can we confirm that this is the expected behavior going forward?

Then we should explicitly specify this in the QA steps; otherwise, it might cause a deploy blocker - since, according to the issue #31218, showing 500 tags on the initial render is the expected behavior.

Staging version

After this PR

[MrMuzyk]

@jayeshmangwani Sure, I can mention this list. But since we're updating all of the lists in the app it's hard for me to mention every single one. Searching the project for usage of SelectionList gives me +100 results

[jayeshmangwani]

Okay cool, let’s not do it for every list - if anything comes up related to the number of items to display, we’ll clarify then.

[jayeshmangwani]

Reviewer Checklist

• I have verified the author checklist is complete (all boxes are checked off).
• I verified the correct issue is linked in the ### Fixed Issues section above
• I verified testing steps are clear and they cover the changes made in this PR
  • I verified the steps for local testing are in the Tests section
  • I verified the steps for Staging and/or Production testing are in the QA steps section
  • I verified the steps cover any possible 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 checked that screenshots or videos are included for tests on all platforms
• I included screenshots or videos for tests on all platforms
• I verified that the composer does not automatically focus or open the keyboard on mobile unless explicitly intended. This includes checking that returning the app from the background does not unexpectedly open the keyboard.
• I verified tests pass on all platforms & I tested again on:
  • Android: HybridApp
  • Android: mWeb Chrome
  • iOS: HybridApp
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
  • MacOS: Desktop
• If there are any errors in the console that are unrelated to this PR, I either fixed them (preferred) or linked to where I reported them in Slack
• I verified there are no new alerts related to the canBeMissing param for useOnyx
• I verified proper code patterns were followed (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
  • 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 verified that this PR follows the guidelines as stated in the Review Guidelines
• I verified other components that can be impacted by these changes have been tested, and I retested again (i.e. if the PR modifies a shared library or component like Avatar, I verified the components using Avatar have been tested & I retested again)
• 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
• If a new component is created I verified that:
  • A similar component doesn't exist in the codebase
  • All props are defined accurately and each prop has a /** comment above it */
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• 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.
• For any bug fix or new feature in this PR, I verified that sufficient unit tests are included to prevent regressions in this 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.
• I have checked off every checkbox in the PR reviewer checklist, including those that don't apply to this PR.

Screenshots/Videos

Android: HybridApp

Android.mov

Android: mWeb Chrome

mweb-chrome.mov

iOS: HybridApp

iOS.mov

iOS: mWeb Safari

mweb-safari.mov

MacOS: Chrome / Safari

web.mov

MacOS: Desktop

desktop.mov

[jayeshmangwani]

LGTM 🚀

[mountiny]

Thanks!

[OSBotify]

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

[s77rt]

This change caused a regression when rendering lists with more than 50 items e.g. country list

Screen.Recording.2025-07-10.at.2.30.26.AM.mov

[jayeshmangwani]

@mountiny @MrMuzyk , Should we consider reverting MAX_SELECTION_LIST_PAGE_LENGTH back to 500 for now, and then investigate and fix the other places where the scrollToIndex out of range error is occurring?

[ikevin127]

I reproduced the crash as well, looks like a deploy blocker if it'll do the same thing on staging / production. Better get it fixed before it hits staging 💯

[jayeshmangwani]

Thanks for reporting this, @ikevin127.
I think we should revert the change back to 500 for now, before the PR hits staging.

[MrMuzyk]

Because there are possibly more places where this happened the best way would probably be to revert that and I will investigate and fix these issues today

[mountiny]

Thanks

[jayeshmangwani]

Thanks, @s77rt, for reporting this - we’ve reverted this PR.

[github-actions]

🚀 Deployed to staging by https://github.com/mountiny in version: 9.1.79-0 🚀

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

[github-actions]

🚀 Deployed to production by https://github.com/Julesssss in version: 9.1.79-11 🚀

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