animate-expo

Use Gesture.Pan with a shared value, capture the current position in onStart, project flick velocity to decide dismissal, and hand velocity to a spring so the animation continues seamlessly. Rubber-band upward overshoot and fire a light haptic when it snaps home.

Use Reanimated for anything a finger touches or anything derived from scroll. Core Animated cannot be driven by a gesture without crossing the bridge, and useNativeDriver only supports transform and opacity, while Reanimated worklets run entirely on the UI thread.

Stutter usually comes from setState in gesture or scroll handlers, animating layout properties like height or width, or scheduling JS calls per frame. Move values into shared values with useAnimatedStyle and judge feel only on a release build.

Use a spring whenever a finger was involved, because springs carry velocity through interruptions. Use timing with an ease-out curve for state-driven changes like entrances, and never use ease-in on UI elements.

Reanimated 4 requires the New Architecture, and babel-preset-expo configures the worklets plugin automatically. Expo Go is not a valid performance environment, so verify feel in a release build on the slowest supported device.

Use expo-haptics: selectionAsync for detents, impactAsync for snaps and commits, and notificationAsync for success or failure. Fire exactly one haptic per user action in the same frame as the visual, scheduled from worklets via scheduleOnRN.