Fall back to react-dom/server.browser in Pages router when React 18 is installed

React 18 has no `react-dom/server.edge`

Author: eps1lon

packages/next/src/server/ReactDOMServerPages.d.ts

@@ -0,0 +1 @@
+export * from 'react-dom/server.edge'

packages/next/src/server/ReactDOMServerPages.js

@@ -0,0 +1,20 @@
+let ReactDOMServer
+
+try {
+  ReactDOMServer = require('react-dom/server.edge')
+} catch (error) {
+  if (
+    // TODO: copilot suggestion. Does this code actually exist?
+    error.code !== 'MODULE_NOT_FOUND' &&
+    // TODO: actually encountered that
+    error.code !== 'ERR_PACKAGE_PATH_NOT_EXPORTED'
+  ) {
+    throw error
+  }
+  // TODO: Ensure App Router does not bundle this
+  // In React versions without react-dom/server.edge, the browser build works in Node.js.
+  // The Node.js build does not support renderToReadableStream.
+  ReactDOMServer = require('react-dom/server.browser')
+}
+
+module.exports = ReactDOMServer

packages/next/src/server/render.tsx

@@ -40,7 +40,7 @@ import type { Revalidate, SwrDelta } from './lib/revalidate'
 import type { COMPILER_NAMES } from '../shared/lib/constants'
 
 import React, { type JSX } from 'react'
-import ReactDOMServerBrowser from 'react-dom/server.browser'
+import ReactDOMServerPages from './ReactDOMServerPages'
 import { StyleRegistry, createStyleRegistry } from 'styled-jsx'
 import {
   GSP_NO_RETURNED_VALUE,
@@ -127,8 +127,7 @@ function noRouter() {
 }
 
 async function renderToString(element: React.ReactElement) {
-  const renderStream =
-    await ReactDOMServerBrowser.renderToReadableStream(element)
+  const renderStream = await ReactDOMServerPages.renderToReadableStream(element)
   await renderStream.allReady
   return streamToString(renderStream)
 }
@@ -1327,7 +1326,7 @@ export async function renderToHTMLImpl(
     ) => {
       const content = renderContent(EnhancedApp, EnhancedComponent)
       return await renderToInitialFizzStream({
-        ReactDOMServer: ReactDOMServerBrowser,
+        ReactDOMServer: ReactDOMServerPages,
         element: content,
       })
     }