如何知道用户何时向上/向下滑动？

let startY;

document.addEventListener('touchstart', (event) => {
    startY = event.touches[0].clientY;
});

document.addEventListener('touchmove', (event) => {
    const currentY = event.touches[0].clientY;
    const deltaY = startY - currentY;

    if (deltaY > 0) {
        console.log('向上滑动');
    } else if (deltaY < 0) {
        console.log('向下滑动');
    }

    startY = currentY;
});

document.addEventListener('wheel', (event) => {
    if (event.deltaY > 0) {
        console.log('向下滚动');
    } else if (event.deltaY < 0) {
        console.log('向上滚动');
    }
});

<script src="https://hammerjs.github.io/dist/hammer.min.js"></script>
<script>
    const element = document.getElementById('yourElementId');
    const hammer = new Hammer(element);

    hammer.on('swipeup', () => {
        console.log('向上滑动');
    });

    hammer.on('swipedown', () => {
        console.log('向下滑动');
    });
</script>