perf(nuxt): reduce nuxt island payload (#26569)

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

@@ -88,30 +88,32 @@ export default defineComponent({
     onMounted(() => { mounted.value = true; teleportKey.value++ })
 
     function setPayload (key: string, result: NuxtIslandResponse) {
+      const toRevive: Partial<NuxtIslandResponse> = {}
+      if (result.props) { toRevive.props = result.props }
+      if (result.slots) { toRevive.slots = result.slots }
+      if (result.components) { toRevive.components = result.components }
+
       nuxtApp.payload.data[key] = {
         __nuxt_island: {
           key,
           ...(import.meta.server && import.meta.prerender)
             ? {}
             : { params: { ...props.context, props: props.props ? JSON.stringify(props.props) : undefined } },
-          result: {
+          result: toRevive
-            props: result.props,
-            slots: result.slots,
-            components: result.components
-          }
         },
         ...result
       }
     }
 
-    const payloads: Required<Pick<NuxtIslandResponse, 'slots' | 'components'>> = {
+    const payloads: Partial<Pick<NuxtIslandResponse, 'slots' | 'components'>> = {}
-      slots: {},
-      components: {}
-    }
 
     if (instance.vnode.el) {
-      payloads.slots = toRaw(nuxtApp.payload.data[`${props.name}_${hashId.value}`])?.slots ?? {}
+      const slots = toRaw(nuxtApp.payload.data[`${props.name}_${hashId.value}`])?.slots
-      payloads.components = toRaw(nuxtApp.payload.data[`${props.name}_${hashId.value}`])?.components ?? {}
+      if (slots) { payloads.slots = slots }
+      if (selectiveClient) {
+        const components = toRaw(nuxtApp.payload.data[`${props.name}_${hashId.value}`])?.components
+        if (components) { payloads.components = components }
+      }
     }
 
     const ssrHTML = ref<string>('')
@@ -137,12 +139,15 @@ export default defineComponent({
         }
       }
 
+      if (payloads.slots) {
         return html.replaceAll(SLOT_FALLBACK_RE, (full, slotName) => {
           if (!currentSlots.includes(slotName)) {
-          return full + (payloads.slots[slotName]?.fallback || '')
+            return full + (payloads.slots?.[slotName]?.fallback || '')
           }
           return full
         })
+      }
+      return html
     })
 
     const cHead = ref<Record<'link' | 'style', Array<Record<string, string>>>>({ link: [], style: [] })
@@ -256,13 +261,14 @@ export default defineComponent({
                 teleports.push(createVNode(Teleport,
                   // use different selectors for even and odd teleportKey to force trigger the teleport
                   { to: import.meta.client ? `${isKeyOdd ? 'div' : ''}[data-island-uid="${uid.value}"][data-island-slot="${slot}"]` : `uid=${uid.value};slot=${slot}` },
-                  { default: () => (payloads.slots[slot].props?.length ? payloads.slots[slot].props : [{}]).map((data: any) => slots[slot]?.(data)) })
+                  { default: () => (payloads.slots?.[slot].props?.length ? payloads.slots[slot].props : [{}]).map((data: any) => slots[slot]?.(data)) })
                 )
               }
             }
             if (selectiveClient) {
               if (import.meta.server) {
-                for (const [id, info] of Object.entries(payloads.components ?? {})) {
+                if (payloads.components) {
+                  for (const [id, info] of Object.entries(payloads.components)) {
                     const { html, slots } = info
                     let replaced = html.replaceAll('data-island-uid', `data-island-uid="${uid.value}"`)
                     for (const slot in slots) {
@@ -272,8 +278,9 @@ export default defineComponent({
                       default: () => [createStaticVNode(replaced, 1)]
                     }))
                   }
-              } else if (canLoadClientComponent.value) {
+                }
-                for (const [id, info] of Object.entries(payloads.components ?? {})) {
+              } else if (canLoadClientComponent.value && payloads.components) {
+                for (const [id, info] of Object.entries(payloads.components)) {
                   const { props, slots } = info
                   const component = components!.get(id)!
                   // use different selectors for even and odd teleportKey to force trigger the teleport

packages/nuxt/src/core/runtime/nitro/renderer.ts

@@ -649,7 +649,7 @@ const SSR_CLIENT_TELEPORT_MARKER = /^uid=([^;]*);client=(.*)$/
 const SSR_CLIENT_SLOT_MARKER = /^island-slot=(?:[^;]*);(.*)$/
 
 function getSlotIslandResponse (ssrContext: NuxtSSRContext): NuxtIslandResponse['slots'] {
-  if (!ssrContext.islandContext) { return {} }
+  if (!ssrContext.islandContext || !Object.keys(ssrContext.islandContext.slots).length) { return undefined }
   const response: NuxtIslandResponse['slots'] = {}
   for (const slot in ssrContext.islandContext.slots) {
     response[slot] = {
@@ -661,7 +661,7 @@ function getSlotIslandResponse (ssrContext: NuxtSSRContext): NuxtIslandResponse[
 }
 
 function getClientIslandResponse (ssrContext: NuxtSSRContext): NuxtIslandResponse['components'] {
-  if (!ssrContext.islandContext) { return {} }
+  if (!ssrContext.islandContext || !Object.keys(ssrContext.islandContext.components).length) { return undefined }
   const response: NuxtIslandResponse['components'] = {}
 
   for (const clientUid in ssrContext.islandContext.components) {

test/basic.test.ts

@@ -1968,14 +1968,12 @@ describe('component islands', () => {
 
     expect(result).toMatchInlineSnapshot(`
       {
-        "components": {},
         "head": {
           "link": [],
           "style": [],
         },
         "html": "<pre data-island-uid>    Route: /foo
         </pre>",
-        "slots": {},
         "state": {},
       }
     `)
@@ -1993,7 +1991,6 @@ describe('component islands', () => {
     result.html = result.html.replaceAll(/ (data-island-uid|data-island-component)="([^"]*)"/g, '')
     expect(result).toMatchInlineSnapshot(`
       {
-        "components": {},
         "head": {
           "link": [],
           "style": [],