refactor: 2.0

src/utils/scroll-into-view.js

@@ -0,0 +1,23 @@
+export default function scrollIntoView (container, selected) {
+  if (!selected) {
+    container.scrollTop = 0
+    return
+  }
+
+  const offsetParents = []
+  let pointer = selected.offsetParent
+  while (pointer && container !== pointer && container.contains(pointer)) {
+    offsetParents.push(pointer)
+    pointer = pointer.offsetParent
+  }
+  const top = selected.offsetTop + offsetParents.reduce((prev, curr) => (prev + curr.offsetTop), 0)
+  const bottom = top + selected.offsetHeight
+  const viewRectTop = container.scrollTop
+  const viewRectBottom = viewRectTop + container.clientHeight
+
+  if (top < viewRectTop) {
+    container.scrollTop = top
+  } else if (bottom > viewRectBottom) {
+    container.scrollTop = bottom - container.clientHeight
+  }
+}