@lancercomet/utils/dist/scroll.js

My personal utils lib.

/**
 * 获取页面滚动高度.
 *
 * @return {number}
 */
function getScrollTop() {
    return document.documentElement.scrollTop ||
        document.body.scrollTop ||
        window.pageYOffset;
}
/**
 * 以动画效果滚动 Y 轴.
 *
 * @param {[number = 0]} y 滚动至目标位置，默认为 0.
 */
function scrollYWithAnimation(y) {
    if (y === void 0) { y = 0; }
    var scrollTop = getScrollTop();
    var delta = y - scrollTop;
    var target = scrollTop + delta * 0.4;
    var reachedTarget = Math.abs(y - target) < 30;
    var reachedEnd = target + window.innerHeight >= (document.documentElement.scrollHeight || document.body.scrollHeight);
    if (reachedTarget || reachedEnd) {
        target = y;
    }
    window.scrollTo(0, target);
    if (target !== y) {
        requestAnimationFrame(function () { return scrollYWithAnimation(y); });
    }
}
/**
 * 检查是否滚动到了顶部.
 */
function checkIsReachTop(element) {
    return element.scrollTop <= 0;
}
/**
 * 检查是否滚动到了底部.
 */
function checkIsReachBottom(element) {
    return element.scrollHeight - element.scrollTop <= element.offsetHeight;
}
export { getScrollTop, scrollYWithAnimation, checkIsReachTop, checkIsReachBottom };