[HOLD for payment 2022-12-20] When you open or create a group chat and tap the Details page (top of page), the last added user in the list blinks and appears.

[kavimuru]

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Action Performed:

1. Open or create a group chat with least 4 or 5 people.
2. Tap into the Details page (tap the top of the group, where the list of chat members are shown)
3. Notice that the latest user blinks and appears right after you open the Detail Page.

Expected Result:

The last user should display as any other user.

Actual Result:

The last user is the only one that blinks.

Workaround:

N/A, this doesn't need a workaround. It's a UI inconsistency.

Platform:

Where is this issue occurring?

• iOS
• Android

Version Number: 1.2.30-0
Reproducible in staging?: Y
Reproducible in production?: Y

RPReplay_Final1669655149.MP4

Expensify/Expensify Issue URL:
Issue reported by: @hungvu193
Slack conversation: https://expensify.slack.com/archives/C049HHMV9SM/p1669655454960459

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[melvin-bot]

Triggered auto assignment to @michaelhaxhiu (Bug), see https://stackoverflow.com/c/expensify/questions/14418 for more details.

[trjExpensify]

I wonder whether this is actually a bug, or more of a choice that was made somewhere for performance reasons to limit the number of members rendered in the list ahead of loading the rest of the participants? We should confirm that.

For example, you can reproduce in a #room with way more than 4/5 participants. It's not the "last participant" that is delayed loading, it's all participants beyond 4.

[melvin-bot]

@michaelhaxhiu Uh oh! This issue is overdue by 2 days. Don't forget to update your issues!

[aldo-expensify]

I wonder whether this is actually a bug, or more of a choice that was made somewhere for performance reasons to limit the number of members rendered in the list ahead of loading the rest of the participants? We should confirm that.

For example, you can reproduce in a #room with way more than 4/5 participants. It's not the "last participant" that is delayed loading, it's all participants beyond 4.

You are right about this being there for performance reasons, but the recommended number is a number that is enough to fill the screen: https://reactnative.dev/docs/flatlist#initialnumtorender. The code is here:

App/src/components/OptionsList/BaseOptionsList.js

Line 232 in 367119d

initialNumToRender={5}

initialNumToRender={5} is too small in my opinion. This depends on the size of the screen, but I think a number around 12 would work better.

[aldo-expensify]

I reproduced this in Android so I added it to the list of devices.

[aldo-expensify]

I'm trying to figure out if we can calculate this number based on the screen size or if we should just pick a fixed higher number like "12"

If we go dynamic, we can get the windowHeight using the HOC withWindowDimensions and do some calculation like props.windowHeight / 64. Each row is using around 64 pixels, and I think at the moment, all usages of the OptionList have rows of this same height. In the future, if OptionList was used to render rows of a different high, the height of a single row (64) could become a prop.