withRepeat not working with withDecay

[InkaAlicja]

Description

Using withRepeat with withDecay doesn't work. I use withDecay to create a bouncing ball effect. But wrapping it with withRepeat doesn't make the animation repeat

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2024-11-25.at.12.07.07.mp4

With repeat expects an animation object (docs), and withDecay returns an animation object (docs), so I think this should work.

I should mention that if I run the animation before the previous one ends, the repeat does seem to kind of work

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2024-11-25.at.12.11.36.mp4

Steps to reproduce

1. Setup a new reanimated app
2. Animate a position of a view with withDecay wrapped with withRepeat:

  const tap = Gesture.Tap()
    .maxDuration(100000)
    .onEnd(() => {
      position.value = withRepeat(withDecay({
        velocity: -1000,
        deceleration: 0.998,
        clamp: [-1, 1],
        velocityFactor: 1,
        rubberBandEffect: true,
        rubberBandFactor: 0.6,
      }),5)
    });

3. Run iOS simulator and tap the circle

(please see the provided snack)

Snack or a link to a repository

https://snack.expo.dev/s_qw5YUp3xjzXDdDXKX5A

Reanimated version

3.16.1

React Native version

0.76.2

Platforms

iOS

JavaScript runtime

None

Workflow

None

Architecture

Fabric (New Architecture)

Build type

None

Device

iOS simulator

Device model

No response

Acknowledgements

Yes

[patrycjakalinska]

Hi @InkaAlicja,

It turned out velocity from withDecay wasn't resetting after each rep. I prepared a PR that should resolve this issue.

Screen.Recording.2024-11-28.at.14.18.54.mov