Flatlist onMomentumScrollEnd called inconsistently between Android and iOS

[clicktodev]

Description

it seems the behavior isn't consistent between android and ios.

on android it works when you flick and release, it also works when you scroll and hold thereby controlling the scrolling.

on IOS it only works when you flick and let the scroll momentum end by itself.

https://reactnative.dev/docs/scrollview#onmomentumscrollend
Called when the momentum scroll ends (scroll which occurs as the ScrollView glides to a stop).
in this case, i believe it means the behavior is incorrect on Android because it's called when it glides to a stop and when the user controls the stop.
or since there's no specific event for when both the scroll and glide are ended by the user controlling it, we should fix the behavior on iOS to behave the same on Android and update the docs to Called when the momentum scroll ends (scroll which occurs as the ScrollView stops).

Steps to reproduce

1. android: flick and release -> momentum end event called
2. android: scroll and hold at one position then release -> momentum end event called
3. ios: flick and release -> momentum end event called
4. ios: scroll via scrollbar, hold then release -> momentum end event is called
5. ios: flick and release via scrollbar -> momentum end event is called
6. ios: scroll, hold at one position then release -> momentum end event is not called

React Native Version

0.76.5

Same behavior on both the new and old architecture

Affected Platforms

Runtime - Android, Runtime - iOS

Output of npx react-native info

expo-env-info 1.2.1 environment info:
    System:
      OS: macOS 14.3.1
      Shell: 5.9 - /bin/zsh
    Binaries:
      Node: 20.18.0 - ~/.nvm/versions/node/v20.18.0/bin/node
      Yarn: 1.22.22 - ~/.nvm/versions/node/v20.18.0/bin/yarn
      npm: 10.8.2 - ~/.nvm/versions/node/v20.18.0/bin/npm
    Managers:
      CocoaPods: 1.16.2 - /opt/homebrew/bin/pod
    SDKs:
      iOS SDK:
        Platforms: DriverKit 23.2, iOS 17.2, macOS 14.2, tvOS 17.2, visionOS 1.0, watchOS 10.2
    IDEs:
      Android Studio: 2022.3 AI-223.8836.35.2231.11090377
      Xcode: 15.2/15C500b - /usr/bin/xcodebuild
    npmPackages:
      expo: ~52.0.23 => 52.0.23 
      expo-router: ~4.0.15 => 4.0.15 
      react: 18.3.1 => 18.3.1 
      react-dom: 18.3.1 => 18.3.1 
      react-native: 0.76.5 => 0.76.5 
      react-native-web: ~0.19.13 => 0.19.13 
    npmGlobalPackages:
      eas-cli: 13.4.2
    Expo Workflow: managed

Stacktrace or Logs

no errors, just inconsistent behavior

Reproducer

https://snack.expo.dev/@hichemfa/onmomentumscrollend-example

Screenshots and Videos

Android:

25-01-01-17-51-42.mp4

iOS:

RPReplay_Final1735750367.mp4

[spyshower]

I have been playing with the exact same thing yesterday. Can confirm.

[react-native-bot]

This issue is stale because it has been open for 180 days with no activity. It will be closed in 7 days unless you comment on it or remove the "Stale" label.

[clicktodev]

still relevant in expo 53

[react-native-bot]

This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[clicktodev]

still relevant in expo 54

[Benj846]

yup can confirm this with RN 0.79.6 and I have scrollto with animated: true
but no event is fired from android

I know there is a fix merged in 0.77 #45187
but still no luck in 0.79.6