onSnapToItem & onBeforeSnapToItem do not fire reliably on left / right edges on Android

Is this a bug report, a feature request, or a question?

Bug report

Have you followed the required steps before opening a bug report?

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• I have read the guidelines regarding bug report.
• I have reviewed the documentation in its entirety, including the dedicated documentations 📚.
• I have searched for existing issues and made sure that the problem hasn't already been reported.
• I am using the latest plugin version.
• I am following the issue template closely in order to produce a useful bug report.

Have you made sure that it wasn't a React Native bug?

Yes.

Is the bug specific to iOS or Android? Or can it be reproduced on both platforms?

Android only, I believe

Is the bug reproductible in a production environment (not a debug one)?

Yes.

Environment

Env:

• React: 16.6.0-alpha.8af6728

• react-native: 0.57.4

• react-native-snap-carousel: 3.7.5

Target platform:

• Android 7.1

Expected Behavior

Expected onSnapToItem to be fired reliably for every index.

Actual Behavior

onSnapToItem does not fire if scrolling all the way to the left or right edges.

gfycat video (look at the bottom for the Active index display)

Reproducible Demo

https://snack.expo.io/SJ6vPURhm

Steps to Reproduce

From the example, scroll to a middle slide on Android.

Scroll all the way to the left or right and release.

The state index is not updated.

Start with the linked Expo reproducible demo and the repository example, reproducing the Android 7.1 behavior by scrolling from a middle slide to either edge. Trace where onSnapToItem and onBeforeSnapToItem are triggered and verify the index state update at both edges. Done means both callbacks fire reliably for every index, including the leftmost and rightmost slides.