elementui中的写法
scrollIntoView (container, selected) {
if (!selected) {
container.scrollTop = 0
return
}
const offsetParents = []
let pointer = selected.offsetParent
// 获取目标节点的上层节点,
// 层层遍历,依次将目标节点的外层节点push到数组中
// Node.contains()返回的是一个布尔值,来表示传入的节点是否为该节点的后代节点
while (pointer && container !== pointer && container.contains(pointer)) {
// 当遍历到上层节点为容器container时终止
offsetParents.push(pointer)
pointer = pointer.offsetParent
}
// reduce出目标节点距离容器的top距离
const top = offsetParents.reduce((prev, curr) => (prev + curr.offsetTop), selected.offsetTop)
// bottom距离即为top距离+目标节点的高度
const bottom = top + selected.offsetHeight
// 容器的已经滚动了的高度,指已经隐藏起来的部分的高度
const viewRectTop = container.scrollTop
// 容器展示的高度 + 容器已经滚动的距离
const viewRectBottom = viewRectTop + container.clientHeight
if (top < viewRectTop) {
container.scrollTop = top
} else if (bottom > viewRectBottom) {
container.scrollTop = bottom - container.clientHeight
}
}
简单粗暴的版本,直接将目标节点滚动到容器中心
if (!selected) {
container.scrollTop = 0
return
}
const offsetParents = []
let pointer = selected.offsetParent
// 获取目标节点的上层节点,
// 层层遍历,依次将目标节点的外层节点push到数组中
// Node.contains()返回的是一个布尔值,来表示传入的节点是否为该节点的后代节点
while (pointer && container !== pointer && container.contains(pointer)) {
// 当遍历到上层节点为容器container时终止
offsetParents.push(pointer)
pointer = pointer.offsetParent
}
// reduce出目标节点距离容器的top距离
const top = offsetParents.reduce((prev, curr) => (prev + curr.offsetTop), selected.offsetTop)
container.scrollTop = top - (container.clientHeight / 2) + selected.clientHeight
}