fix(nuxt): use key to force server component re-rendering

packages/nuxt/src/app/components/nuxt-island.ts

@@ -1,4 +1,5 @@
-import { computed, createStaticVNode, defineComponent, getCurrentInstance, ref, watch } from 'vue'
+import type { RendererNode } from 'vue'
+import { computed, createStaticVNode, defineComponent, getCurrentInstance, h, ref, watch } from 'vue'
 import { debounce } from 'perfect-debounce'
 import { hash } from 'ohash'
 import { appendHeader } from 'h3'
@@ -33,7 +34,7 @@ export default defineComponent({
     const instance = getCurrentInstance()!
     const event = useRequestEvent()
 
-    const html = ref<string>(process.client ? instance.vnode.el?.outerHTML ?? '<div></div>' : '<div></div>')
+    const html = ref<string>(process.client ? getFragmentHTML(instance?.vnode?.el).join('') ?? '<div></div>' : '<div></div>')
     const cHead = ref<Record<'link' | 'style', Array<Record<string, string>>>>({ link: [], style: [] })
     useHead(cHead)
 
@@ -51,7 +52,7 @@ export default defineComponent({
         }
       })
     }
-
+    const key = ref(0)
     async function fetchComponent () {
       nuxtApp[pKey] = nuxtApp[pKey] || {}
       if (!nuxtApp[pKey][hashId.value]) {
@@ -63,6 +64,7 @@ export default defineComponent({
       cHead.value.link = res.head.link
       cHead.value.style = res.head.style
       html.value = res.html
+      key.value++
     }
 
     if (process.client) {
@@ -72,7 +74,40 @@ export default defineComponent({
     if (process.server || !nuxtApp.isHydrating) {
       await fetchComponent()
     }
-
-    return () => createStaticVNode(html.value, 1)
+    return () => h((_, { slots }) => slots.default?.(), { key: key.value }, {
+      default: () => [createStaticVNode(html.value, 1)]
+    })
   }
 })
+
+// TODO refactor with https://github.com/nuxt/nuxt/pull/19231
+function getFragmentHTML (element: RendererNode | null) {
+  if (element) {
+    if (element.nodeName === '#comment' && element.nodeValue === '[') {
+      return getFragmentChildren(element)
+    }
+    return [element.outerHTML]
+  }
+  return []
+}
+
+function getFragmentChildren (element: RendererNode | null, blocks: string[] = []) {
+  if (element && element.nodeName) {
+    if (isEndFragment(element)) {
+      return blocks
+    } else if (!isStartFragment(element)) {
+      blocks.push(element.outerHTML)
+    }
+
+    getFragmentChildren(element.nextSibling, blocks)
+  }
+  return blocks
+}
+
+function isStartFragment (element: RendererNode) {
+  return element.nodeName === '#comment' && element.nodeValue === '['
+}
+
+function isEndFragment (element: RendererNode) {
+  return element.nodeName === '#comment' && element.nodeValue === ']'
+}

packages/nuxt/src/components/runtime/server-component.ts

@@ -1,4 +1,4 @@
-import { computed, createStaticVNode, defineComponent, h, watch } from 'vue'
+import { Fragment, computed, createStaticVNode, createVNode, defineComponent, h, ref, watch } from 'vue'
 import { debounce } from 'perfect-debounce'
 import { hash } from 'ohash'
 import { appendHeader } from 'h3'
@@ -42,6 +42,7 @@ const NuxtServerComponent = defineComponent({
   },
   async setup (props) {
     const nuxtApp = useNuxtApp()
+    const key = ref(0)
     const hashId = computed(() => hash([props.name, props.props, props.context]))
 
     const event = useRequestEvent()
@@ -92,11 +93,14 @@ const NuxtServerComponent = defineComponent({
     useHead(() => res.data.value!.head)
 
     if (process.client) {
-      watch(props, debounce(() => res.execute(), 100))
+      watch(props, debounce(async () => {
+        await res.execute()
+        key.value++
+      }, 100))
     }
 
     await res
 
-    return () => createStaticVNode(res.data.value!.html, 1)
+    return () => createVNode(Fragment, { key: key.value }, [createStaticVNode(res.data.value!.html, 1)])
   }
 })

test/basic.test.ts

@@ -337,6 +337,23 @@ describe('pages', () => {
 
     await page.close()
   })
+
+  it('/islands', async () => {
+    const page = await createPage('/islands')
+    await page.waitForLoadState('networkidle')
+    await page.locator('#increase-pure-component').click()
+    await page.waitForResponse(response => response.url().includes('/__nuxt_island/') && response.status() === 200)
+    await page.waitForLoadState('networkidle')
+    expect(await page.locator('.box').innerHTML()).toContain('"number": 101,')
+    await page.locator('#count-async-server-long-async').click()
+    await Promise.all([
+      page.waitForResponse(response => response.url().includes('/__nuxt_island/LongAsyncComponent') && response.status() === 200),
+      page.waitForResponse(response => response.url().includes('/__nuxt_island/AsyncServerComponent') && response.status() === 200)
+    ])
+    await page.waitForLoadState('networkidle')
+    expect(await page.locator('#async-server-component-count').innerHTML()).toContain(('1'))
+    expect(await page.locator('#long-async-component-count').innerHTML()).toContain('1')
+  })
 })
 
 describe('rich payloads', () => {
@@ -1109,7 +1126,7 @@ describe('component islands', () => {
     const result: NuxtIslandResponse = await $fetch('/__nuxt_island/RouteComponent?url=/foo')
 
     if (isDev()) {
-      result.head.link = result.head.link.filter(l => !l.href.includes('@nuxt+ui-templates'))
+      result.head.link = result.head.link.filter(l => !l.href.includes('@nuxt+ui-templates') && (l.href.startsWith('_nuxt/components/islands/') && l.href.includes('_nuxt/components/islands/RouteComponent')))
     }
 
     expect(result).toMatchInlineSnapshot(`
@@ -1132,7 +1149,7 @@ describe('component islands', () => {
       })
     }))
     if (isDev()) {
-      result.head.link = result.head.link.filter(l => !l.href.includes('@nuxt+ui-templates'))
+      result.head.link = result.head.link.filter(l => !l.href.includes('@nuxt+ui-templates') && (l.href.startsWith('_nuxt/components/islands/') && l.href.includes('_nuxt/components/islands/LongAsyncComponent')))
     }
     expect(result).toMatchInlineSnapshot(`
       {
@@ -1153,7 +1170,7 @@ describe('component islands', () => {
       })
     }))
     if (isDev()) {
-      result.head.link = result.head.link.filter(l => !l.href.includes('@nuxt+ui-templates'))
+      result.head.link = result.head.link.filter(l => !l.href.includes('@nuxt+ui-templates') && (l.href.startsWith('_nuxt/components/islands/') && l.href.includes('_nuxt/components/islands/AsyncServerComponent')))
     }
     expect(result).toMatchInlineSnapshot(`
     {

test/fixtures/basic/pages/islands.vue

@@ -18,15 +18,15 @@ const count = ref(0)
       <NuxtIsland name="PureComponent" :props="islandProps" />
       <NuxtIsland name="PureComponent" :props="islandProps" />
     </div>
-    <button @click="islandProps.number++">
+    <button id="increase-pure-component" @click="islandProps.number++">
       Increase
     </button>
     <hr>
     Route island component:
     <div v-if="routeIslandVisible" class="box">
       <NuxtIsland name="RouteComponent" :context="{ url: '/test' }" />
     </div>
-    <button v-else @click="routeIslandVisible = true">
+    <button v-else id="show-route" @click="routeIslandVisible = true">
       Show
     </button>
 
@@ -35,7 +35,7 @@ const count = ref(0)
     <div>
       Async island component (20ms):
       <NuxtIsland name="LongAsyncComponent" :props="{ count }" />
-      <button @click="count++">
+      <button id="count-async-server-long-async" @click="count++">
         add +1 to count
       </button>
     </div>