Function onWheel

demo/App.tsx:247–251

(e: WheelEvent)

    let touchStartY = 0;

    const onWheel = (e: WheelEvent) => {
      if (e.deltaY < 0) {
        userScrolledUpRef.current = true;
      }
    };
    const onTouchStart = (e: TouchEvent) => {
      touchStartY = e.touches[0]?.clientY ?? 0;
    };