Update entry.server docs on optionality

Author: brophdawg11

docs/api/framework-conventions/entry.server.tsx.md

@@ -9,17 +9,18 @@ order: 5
 
 ## Summary
 
-<docs-info>
-This file is optional
-</docs-info>
-
 This file is the server-side entry point that controls how your React Router application generates HTTP responses on the server.
 
 This module should render the markup for the current page using a [`<ServerRouter>`][serverrouter] element with the `context` and `url` for the current request. This markup will (optionally) be re-hydrated once JavaScript loads in the browser using the [client entry module][client-entry].
 
+<docs-info>This file is optional if you are running on Node. If it is not present, a [default implementation][node-streaming-entry-server] will be used.
+<br/>
+<br/>
+If you are using another runtime (i.e., Cloudflare) then you need to include this file. You can find sample implementations in the [templates repository][templates-repo].</docs-info>
+
 ## Generating `entry.server.tsx`
 
-By default, React Router will handle generating the HTTP Response for you. You can reveal the default entry server file with the following:
+When running in Node, React Router will handle generating the HTTP Response for you. You can reveal the default entry server file with the following:
 
 ```shellscript nonumber
 npx react-router reveal
@@ -42,7 +43,7 @@ export default function handleRequest(
   request: Request,
   responseStatusCode: number,
   responseHeaders: Headers,
-  routerContext: EntryContext
+  routerContext: EntryContext,
 ) {
   return new Promise((resolve, reject) => {
     const { pipe, abort } = renderToPipeableStream(
@@ -62,15 +63,15 @@ export default function handleRequest(
             new Response(stream, {
               headers: responseHeaders,
               status: responseStatusCode,
-            })
+            }),
           );
 
           pipe(body);
         },
         onShellError(error: unknown) {
           reject(error);
         },
-      }
+      },
     );
   });
 }
@@ -113,7 +114,7 @@ export function handleDataRequest(
     request,
     params,
     context,
-  }: LoaderFunctionArgs | ActionFunctionArgs
+  }: LoaderFunctionArgs | ActionFunctionArgs,
 ) {
   response.headers.set("X-Custom-Header", "value");
   return response;
@@ -131,7 +132,7 @@ export function handleError(
     request,
     params,
     context,
-  }: LoaderFunctionArgs | ActionFunctionArgs
+  }: LoaderFunctionArgs | ActionFunctionArgs,
 ) {
   if (!request.signal.aborted) {
     sendErrorToErrorReportingService(error);
@@ -160,3 +161,4 @@ Note that this does not handle thrown `Response` instances from your `loader`/`a
 [rendertopipeablestream]: https://react.dev/reference/react-dom/server/renderToPipeableStream
 [rendertoreadablestream]: https://react.dev/reference/react-dom/server/renderToReadableStream
 [node-streaming-entry-server]: https://github.com/remix-run/react-router/blob/dev/packages/react-router-dev/config/defaults/entry.server.node.tsx
+[templates-repo]: https://github.com/remix-run/react-router-templates