diffClamp on v2

[neiker]

I'm translating a Animated.View inside a PanGestureHandler using useAnimatedGestureHandler and useAnimatedStyle hooks
I wrote a worklet to clamp de value:

const clamp = (value: number, lowerBound: number, upperBound: number) => {
  "worklet";
  return Math.min(Math.max(lowerBound, value), upperBound);
};

and I'm using it inside the onActive.

It works but I can't figure it out the way to store the diff and subtract it on the next onActive

const gestureHandler = useAnimatedGestureHandler<
    PanGestureHandlerGestureEvent,
    { startY: number }
  >({
    onStart: (_, ctx) => {
      ctx.startY = y.value;
    },
    onActive: (event, ctx) => {
      // TODO diffClamp
      const value = ctx.startY + event.translationY;
      const clampedValue = clamp(value, -headerHeight, 0);

      y.value = clampedValue;
    },
  });

[neiker]

I solved this by storing the previous value of translationY:

const gestureHandler = useAnimatedGestureHandler<
    PanGestureHandlerGestureEvent,
    { prevY: number }
  >({
    onStart: (_, ctx) => {
      ctx.prevY = 0;
    },
    onActive: (event, ctx) => {
      const diff = event.translationY - ctx.prevY;

      y.value = clamp(
        y.value + diff,
        -headerHeight,
        0
      );

      ctx.prevY = event.translationY;
    },
  });