@motion-probe/react-native

The in-app half of motion-probe: an Expo Module that records what the native view layer actually renders on every display frame — position, transform, opacity, clipping, occlusion, scrolling — for the views you name by testID (iOS: CADisplayLink + presentation layer, Android: Choreographer + view matrix).

It works regardless of what drives the animation (Animated with or without the native driver, Reanimated, layout transitions, scroll views), and it never needs a screen recording.

Install (development builds)

npx expo install @motion-probe/react-native

import { installMotionProbe } from '@motion-probe/react-native';

if (__DEV__) installMotionProbe();

Rebuild the app once (native code; Expo Go is not supported). The app dials the local motion-probe daemon at ws://<metro host>:7357/app; on an Android emulator run adb reverse tcp:7357 tcp:7357.

Deterministic triggers (optional)

Register handlers that scripts and agents can call with motion-probe send <name> or motion-probe record --send <name> — no deep links (iOS simulators confirm every openurl) and no UI automation:

import { onMotionProbeCommand } from '@motion-probe/react-native';

useEffect(
  () =>
    onMotionProbeCommand((name) => {
      if (name !== 'open-sheet') return false; // not mine
      setSheetOpen(true);
    }),
  [],
);

Then record and verify with @motion-probe/cli or the @motion-probe/mcp server.

License

MIT