fix(components): [carousel] improper active item (#8904)

* fix(components): [carousel] none of active item

closed #8891

* fix: ts error

* fix: guarantee items order when reusing carousel-item component

* style: code format

* fix: test fail

* chore: correct type

* fix: sorting failed in some cases

* better implementation

better implementation

* impove code accroding to review comment

packages/components/carousel/__tests__/carousel.test.tsx

@@ -195,4 +195,30 @@ describe('Carousel', () => {
     await wait(60)
     expect(items[1].classList.contains('is-active')).toBeTruthy()
   })
+  it('should guarantee order of indicators', async () => {
+    const data = reactive([1, 2, 3, 4])
+    wrapper = mount({
+      setup() {
+        return () => (
+          <div>
+            <Carousel>
+              {data.map((value) => (
+                <CarouselItem label={value} key={value}>
+                  {value}
+                </CarouselItem>
+              ))}
+            </Carousel>
+          </div>
+        )
+      },
+    })
+    await nextTick()
+
+    data.splice(1, 0, 5)
+    await nextTick()
+    const indicators = wrapper.findAll('.el-carousel__button')
+    data.forEach((value, index) => {
+      expect(indicators[index].element.textContent).toEqual(value.toString())
+    })
+  })
 })

packages/components/carousel/src/carousel.vue

@@ -64,7 +64,7 @@
 <script lang="ts" setup>
 import {
   computed,
-  nextTick,
+  getCurrentInstance,
   onBeforeUnmount,
   onMounted,
   provide,
@@ -78,7 +78,7 @@ import { useResizeObserver } from '@vueuse/core'
 import { debugWarn, isString } from '@element-plus/utils'
 import { ElIcon } from '@element-plus/components/icon'
 import { ArrowLeft, ArrowRight } from '@element-plus/icons-vue'
-import { useNamespace } from '@element-plus/hooks'
+import { useNamespace, useOrderedChildren } from '@element-plus/hooks'
 import { carouselContextKey } from '@element-plus/tokens'
 import { carouselEmits, carouselProps } from './carousel'
 import type { CarouselItemContext } from '@element-plus/tokens'
@@ -93,12 +93,20 @@ const ns = useNamespace('carousel')
 const COMPONENT_NAME = 'ElCarousel'
 const THROTTLE_TIME = 300
 
+const {
+  children: items,
+  addChild: addItem,
+  removeChild: removeItem,
+} = useOrderedChildren<CarouselItemContext>(
+  getCurrentInstance()!,
+  'ElCarouselItem'
+)
+
 // refs
 const activeIndex = ref(-1)
 const timer = ref<ReturnType<typeof setInterval> | null>(null)
 const hover = ref(false)
 const root = ref<HTMLDivElement>()
-const items = ref<Array<CarouselItemContext>>([])
 
 // computed
 const arrowDisplay = computed(
@@ -199,18 +207,6 @@ function resetItemPosition(oldIndex?: number) {
   })
 }
 
-function addItem(item: CarouselItemContext) {
-  items.value.push(item)
-}
-
-function removeItem(uid?: number) {
-  const index = items.value.findIndex((item) => item.uid === uid)
-  if (index !== -1) {
-    items.value.splice(index, 1)
-    if (activeIndex.value === index) next()
-  }
-}
-
 function itemInStage(item: CarouselItemContext, index: number) {
   const _items = unref(items)
   const itemCount = _items.length
@@ -312,17 +308,19 @@ watch(
   }
 )
 
+watch(
+  () => items.value,
+  () => {
+    if (items.value.length > 0) setActiveItem(props.initialIndex)
+  }
+)
+
 const resizeObserver = shallowRef<ReturnType<typeof useResizeObserver>>()
 // lifecycle
-onMounted(async () => {
-  await nextTick()
-
+onMounted(() => {
   resizeObserver.value = useResizeObserver(root.value, () => {
     resetItemPosition()
   })
-  if (props.initialIndex < items.value.length && props.initialIndex >= 0) {
-    activeIndex.value = props.initialIndex
-  }
   startTimer()
 })
 

packages/hooks/index.ts

@@ -28,3 +28,4 @@ export * from './use-namespace'
 export * from './use-z-index'
 export * from './use-floating'
 export * from './use-cursor'
+export * from './use-ordered-children'

packages/hooks/use-ordered-children/index.ts

@@ -0,0 +1,44 @@
+import { shallowRef } from 'vue'
+import { flattedChildren, isVNode } from '@element-plus/utils'
+
+import type { ComponentInternalInstance, VNode } from 'vue'
+
+const getOrderedChildren = <T>(
+  vm: ComponentInternalInstance,
+  childComponentName: string,
+  children: Record<number, T>
+): T[] => {
+  const nodes = flattedChildren(vm.subTree).filter(
+    (n): n is VNode =>
+      isVNode(n) &&
+      (n.type as any)?.name === childComponentName &&
+      !!n.component
+  )
+  const uids = nodes.map((n) => n.component!.uid)
+  return uids.map((uid) => children[uid]).filter((p) => !!p)
+}
+
+export const useOrderedChildren = <T extends { uid: number }>(
+  vm: ComponentInternalInstance,
+  childComponentName: string
+) => {
+  const children: Record<number, T> = {}
+  const orderedChildren = shallowRef<T[]>([])
+
+  const addChild = (child: T) => {
+    children[child.uid] = child
+    orderedChildren.value = getOrderedChildren(vm, childComponentName, children)
+  }
+  const removeChild = (uid: number) => {
+    delete children[uid]
+    orderedChildren.value = orderedChildren.value.filter(
+      (children) => children.uid !== uid
+    )
+  }
+
+  return {
+    children: orderedChildren,
+    addChild,
+    removeChild,
+  }
+}

packages/tokens/carousel.ts

@@ -15,7 +15,7 @@ export type CarouselItemStates = {
 export type CarouselItemContext = {
   props: CarouselItemProps
   states: CarouselItemStates
-  uid: number | undefined
+  uid: number
   translateItem: (index: number, activeIndex: number, oldIndex?: number) => void
 }
 
@@ -26,7 +26,7 @@ export type CarouselContext = {
   isVertical: Ref<boolean>
   loop: boolean
   addItem: (item: CarouselItemContext) => void
-  removeItem: (uid: number | undefined) => void
+  removeItem: (uid: number) => void
   setActiveItem: (index: number) => void
 }