From 899b1bb6903849d3763dfc50c9944200ff048327 Mon Sep 17 00:00:00 2001
From: Shu Ding <g@shud.in>
Date: Thu, 29 Sep 2022 15:56:51 +0200
Subject: [PATCH] make sure polyfill is added in app

---
 packages/next/server/app-render.tsx           | 27 +++++++++++++------
 .../next/server/node-web-streams-helper.ts    | 12 ++++++++-
 test/e2e/app-dir/index.test.ts                |  7 +++++
 3 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/packages/next/server/app-render.tsx b/packages/next/server/app-render.tsx
index 4975b86ba9a00..e2f6f072797ae 100644
--- a/packages/next/server/app-render.tsx
+++ b/packages/next/server/app-render.tsx
@@ -1287,6 +1287,13 @@ export async function renderToHTMLOrFlight(
         return flushed
       }
 
+      const polyfills = buildManifest.polyfillFiles
+        .filter(
+          (polyfill) =>
+            polyfill.endsWith('.js') && !polyfill.endsWith('.module.js')
+        )
+        .map((polyfill) => `${renderOpts.assetPrefix || ''}/_next/${polyfill}`)
+
       try {
         const renderStream = await renderToInitialStream({
           ReactDOMServer,
@@ -1295,14 +1302,16 @@ export async function renderToHTMLOrFlight(
             onError: htmlRendererErrorHandler,
             nonce,
             // Include hydration scripts in the HTML
-            bootstrapScripts: subresourceIntegrityManifest
-              ? buildManifest.rootMainFiles.map((src) => ({
-                  src: `${renderOpts.assetPrefix || ''}/_next/` + src,
-                  integrity: subresourceIntegrityManifest[src],
-                }))
-              : buildManifest.rootMainFiles.map(
-                  (src) => `${renderOpts.assetPrefix || ''}/_next/` + src
-                ),
+            bootstrapScripts: [
+              ...(subresourceIntegrityManifest
+                ? buildManifest.rootMainFiles.map((src) => ({
+                    src: `${renderOpts.assetPrefix || ''}/_next/` + src,
+                    integrity: subresourceIntegrityManifest[src],
+                  }))
+                : buildManifest.rootMainFiles.map(
+                    (src) => `${renderOpts.assetPrefix || ''}/_next/` + src
+                  )),
+            ],
           },
         })
 
@@ -1311,6 +1320,7 @@ export async function renderToHTMLOrFlight(
           generateStaticHTML: generateStaticHTML,
           flushEffectHandler,
           flushEffectsToHead: true,
+          polyfills,
         })
       } catch (err: any) {
         // TODO-APP: show error overlay in development. `element` should probably be wrapped in AppRouter for this case.
@@ -1341,6 +1351,7 @@ export async function renderToHTMLOrFlight(
           generateStaticHTML: generateStaticHTML,
           flushEffectHandler,
           flushEffectsToHead: true,
+          polyfills,
         })
       }
     }
diff --git a/packages/next/server/node-web-streams-helper.ts b/packages/next/server/node-web-streams-helper.ts
index 9e6bdfb203d7e..77b759f2ecf4f 100644
--- a/packages/next/server/node-web-streams-helper.ts
+++ b/packages/next/server/node-web-streams-helper.ts
@@ -265,12 +265,14 @@ export async function continueFromInitialStream(
     generateStaticHTML,
     flushEffectHandler,
     flushEffectsToHead,
+    polyfills,
   }: {
     suffix?: string
     dataStream?: ReadableStream<Uint8Array>
     generateStaticHTML: boolean
     flushEffectHandler?: () => Promise<string>
     flushEffectsToHead: boolean
+    polyfills?: string[]
   }
 ): Promise<ReadableStream<Uint8Array>> {
   const closeTag = '</body></html>'
@@ -289,13 +291,21 @@ export async function continueFromInitialStream(
     dataStream ? createInlineDataStream(dataStream) : null,
     suffixUnclosed != null ? createSuffixStream(closeTag) : null,
     createHeadInjectionTransformStream(async () => {
+      // Inject polyfills for browsers that don't support modules. It has to be
+      // blocking here and can't be `defer` because other scripts have `async`.
+      const polyfillScripts = polyfills
+        ? polyfills
+            .map((src) => `<script src="${src}" nomodule=""></script>`)
+            .join('')
+        : ''
+
       // TODO-APP: Inject flush effects to end of head in app layout rendering, to avoid
       // hydration errors. Remove this once it's ready to be handled by react itself.
       const flushEffectsContent =
         flushEffectHandler && flushEffectsToHead
           ? await flushEffectHandler()
           : ''
-      return flushEffectsContent
+      return polyfillScripts + flushEffectsContent
     }),
   ].filter(nonNullable)
 
diff --git a/test/e2e/app-dir/index.test.ts b/test/e2e/app-dir/index.test.ts
index c67d345bb0d35..9b88201286c8b 100644
--- a/test/e2e/app-dir/index.test.ts
+++ b/test/e2e/app-dir/index.test.ts
@@ -99,6 +99,13 @@ describe('app dir', () => {
       expect(html).toContain('hello from dynamic on client')
     })
 
+    it('should serve polyfills for browsers that do not support modules', async () => {
+      const html = await renderViaHTTP(next.url, '/dashboard/index')
+      expect(html).toMatch(
+        /<script src="\/_next\/static\/chunks\/polyfills(-\w+)?\.js" nomodule="">/
+      )
+    })
+
     // TODO-APP: handle css modules fouc in dev
     it.skip('should handle css imports in next/dynamic correctly', async () => {
       const browser = await webdriver(next.url, '/dashboard/index')