fix(TransitionGroup): should collect raw children with Fragment

fix vuejs#1045

packages/runtime-dom/src/components/TransitionGroup.ts

@@ -101,12 +101,7 @@ const TransitionGroupImpl = {
  const cssTransitionProps = resolveTransitionProps(rawProps)
  const tag = rawProps.tag || Fragment
  prevChildren = children
- children = slots.default ? slots.default() : []
-
- // handle fragment children case, e.g. v-for
- if (children.length === 1 && children[0].type === Fragment) {
- children = children[0].children as VNode[]
- }
+ children = getTransitionRawChildren(slots.default ? slots.default() : [])
 
  for (let i = 0; i < children.length; i++) {
  const child = children[i]
@@ -136,6 +131,20 @@ const TransitionGroupImpl = {
  }
 }
 
+function getTransitionRawChildren(children: VNode[]): VNode[] {
+ let array: VNode[] = []
+ for (const child of children) {
+ const { type, children } = child
+ // handle fragment children case, e.g. v-for
+ if (type === Fragment) {
+ array = array.concat(getTransitionRawChildren(children as VNode[]))
+ } else {
+ array.push(child)
+ }
+ }
+ return array
+}
+
 // remove mode props as TransitionGroup doesn't support it
 delete TransitionGroupImpl.props.mode