From f2ca0a9377e73fb636ad70159487f4b531bc8683 Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Wed, 28 Sep 2022 12:27:26 +0100
Subject: [PATCH 1/3] perf(nitro): respond with early hints in node-based
 environments

---
 packages/nuxt/src/core/runtime/nitro/renderer.ts | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/packages/nuxt/src/core/runtime/nitro/renderer.ts b/packages/nuxt/src/core/runtime/nitro/renderer.ts
index fcb56a73f75..40e3efdb185 100644
--- a/packages/nuxt/src/core/runtime/nitro/renderer.ts
+++ b/packages/nuxt/src/core/runtime/nitro/renderer.ts
@@ -148,6 +148,12 @@ export default defineRenderHandler(async (event) => {
     ssrContext.payload.prerenderedAt = Date.now()
   }
 
+  if (!isRenderingPayload && !process.env.prerender && event.res.socket) {
+    const { link } = await getEarlyHints()
+    // TODO: use https://github.com/nodejs/node/pull/44180 when we drop support for node 16
+    event.res.socket!.write(`HTTP/1.1 103 Early Hints\r\nLink: ${link}\r\n\r\n`, 'utf-8',)
+  }
+
   // Render app
   const renderer = (process.env.NUXT_NO_SSR || ssrContext.noSSR) ? await getSPARenderer() : await getSSRRenderer()
   const _rendered = await renderer.renderToString(ssrContext).catch((err) => {
@@ -303,3 +309,11 @@ function splitPayload (ssrContext: NuxtSSRContext) {
     payload: { data, prerenderedAt }
   }
 }
+
+const getEarlyHints = lazyCachedFunction(async () => {
+  const renderer = process.env.NUXT_NO_SSR ? await getSPARenderer() : await getSSRRenderer()
+  const result = await renderer.renderToString({
+    runtimeConfig: useRuntimeConfig() as NuxtSSRContext['runtimeConfig'],
+  } as any)
+  return result.renderResourceHeaders()
+})

From dc2e983826b212c54630fa51795c794a4183476d Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Wed, 28 Sep 2022 13:11:53 +0100
Subject: [PATCH 2/3] perf: remove extra render cycle on first request

---
 .../nuxt/src/core/runtime/nitro/renderer.ts   | 23 ++++++++-----------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/packages/nuxt/src/core/runtime/nitro/renderer.ts b/packages/nuxt/src/core/runtime/nitro/renderer.ts
index 40e3efdb185..2e2eb8a046c 100644
--- a/packages/nuxt/src/core/runtime/nitro/renderer.ts
+++ b/packages/nuxt/src/core/runtime/nitro/renderer.ts
@@ -1,4 +1,4 @@
-import { createRenderer } from 'vue-bundle-renderer/runtime'
+import { createRenderer, renderResourceHeaders } from 'vue-bundle-renderer/runtime'
 import type { RenderResponse } from 'nitropack'
 import type { Manifest } from 'vite'
 import { appendHeader, getQuery } from 'h3'
@@ -100,7 +100,10 @@ const getSPARenderer = lazyCachedFunction(async () => {
     return Promise.resolve(result)
   }
 
-  return { renderToString }
+  return {
+    rendererContext: renderer.rendererContext,
+    renderToString
+  }
 })
 
 const PAYLOAD_CACHE = (process.env.NUXT_PAYLOAD_EXTRACTION && process.env.prerender) ? new Map() : null // TODO: Use LRU cache
@@ -148,14 +151,16 @@ export default defineRenderHandler(async (event) => {
     ssrContext.payload.prerenderedAt = Date.now()
   }
 
+  // Render app
+  const renderer = (process.env.NUXT_NO_SSR || ssrContext.noSSR) ? await getSPARenderer() : await getSSRRenderer()
+
+  // Render 103 Early Hints
   if (!isRenderingPayload && !process.env.prerender && event.res.socket) {
-    const { link } = await getEarlyHints()
+    const { link } = renderResourceHeaders({}, renderer.rendererContext)
     // TODO: use https://github.com/nodejs/node/pull/44180 when we drop support for node 16
     event.res.socket!.write(`HTTP/1.1 103 Early Hints\r\nLink: ${link}\r\n\r\n`, 'utf-8',)
   }
 
-  // Render app
-  const renderer = (process.env.NUXT_NO_SSR || ssrContext.noSSR) ? await getSPARenderer() : await getSSRRenderer()
   const _rendered = await renderer.renderToString(ssrContext).catch((err) => {
     if (!ssrError) {
       // Use explicitly thrown error in preference to subsequent rendering errors
@@ -309,11 +314,3 @@ function splitPayload (ssrContext: NuxtSSRContext) {
     payload: { data, prerenderedAt }
   }
 }
-
-const getEarlyHints = lazyCachedFunction(async () => {
-  const renderer = process.env.NUXT_NO_SSR ? await getSPARenderer() : await getSSRRenderer()
-  const result = await renderer.renderToString({
-    runtimeConfig: useRuntimeConfig() as NuxtSSRContext['runtimeConfig'],
-  } as any)
-  return result.renderResourceHeaders()
-})

From 55ff9ddafe120e98f91ffda654725dab9ee45152 Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Wed, 28 Sep 2022 13:16:31 +0100
Subject: [PATCH 3/3] style: remove trailing comma

---
 packages/nuxt/src/core/runtime/nitro/renderer.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/nuxt/src/core/runtime/nitro/renderer.ts b/packages/nuxt/src/core/runtime/nitro/renderer.ts
index 2e2eb8a046c..828aec1a84f 100644
--- a/packages/nuxt/src/core/runtime/nitro/renderer.ts
+++ b/packages/nuxt/src/core/runtime/nitro/renderer.ts
@@ -158,7 +158,7 @@ export default defineRenderHandler(async (event) => {
   if (!isRenderingPayload && !process.env.prerender && event.res.socket) {
     const { link } = renderResourceHeaders({}, renderer.rendererContext)
     // TODO: use https://github.com/nodejs/node/pull/44180 when we drop support for node 16
-    event.res.socket!.write(`HTTP/1.1 103 Early Hints\r\nLink: ${link}\r\n\r\n`, 'utf-8',)
+    event.res.socket!.write(`HTTP/1.1 103 Early Hints\r\nLink: ${link}\r\n\r\n`, 'utf-8')
   }
 
   const _rendered = await renderer.renderToString(ssrContext).catch((err) => {