Only expose the $$FORM_ACTION extension in SSR builds

We assume that only the Edge or Node builds of the client are used
together with SSR. On the client this feature is not needed so we can
exclude the code. This might be a bit unnecessary because it's not that
much code and in theory you might use SSR in a Service Worker or something
where the Browser build would be used but currently we assume that build is
only for the client. That's why it also don't take an option for reverse
look up of file names.

packages/react-client/src/ReactFlightClient.js

@@ -29,6 +29,7 @@ import {
   readPartialStringChunk,
   readFinalStringChunk,
   createStringDecoder,
+  usedWithSSR,
 } from './ReactFlightClientConfig';
 
 import {
@@ -529,8 +530,10 @@ function createServerReferenceProxy<A: Iterable<any>, T>(
     });
   };
   // Expose encoder for use by SSR.
-  // TODO: Only expose this in SSR builds and not the browser client.
-  proxy.$$FORM_ACTION = encodeFormAction;
+  if (usedWithSSR) {
+    // Only expose this in builds that would actually use it. Not needed on the client.
+    (proxy: any).$$FORM_ACTION = encodeFormAction;
+  }
   knownServerReferences.set(proxy, metaData);
   return proxy;
 }

packages/react-client/src/ReactFlightReplyClient.js

@@ -28,6 +28,8 @@ import type {
   RejectedThenable,
 } from '../../shared/ReactTypes';
 
+import {usedWithSSR} from './ReactFlightClientConfig';
+
 type ReactJSONValue =
   | string
   | boolean
@@ -466,8 +468,10 @@ export function createServerReference<A: Iterable<any>, T>(
     return callServer(id, args);
   };
   // Expose encoder for use by SSR.
-  // TODO: Only expose this in SSR builds and not the browser client.
-  proxy.$$FORM_ACTION = encodeFormAction;
+  if (usedWithSSR) {
+    // Only expose this in builds that would actually use it. Not needed on the client.
+    (proxy: any).$$FORM_ACTION = encodeFormAction;
+  }
   knownServerReferences.set(proxy, {id: id, bound: null});
   return proxy;
 }

packages/react-client/src/forks/ReactFlightClientConfig.custom.js

@@ -35,6 +35,7 @@ export const resolveServerReference = $$$config.resolveServerReference;
 export const preloadModule = $$$config.preloadModule;
 export const requireModule = $$$config.requireModule;
 export const dispatchHint = $$$config.dispatchHint;
+export const usedWithSSR = true;
 
 export opaque type Source = mixed;
 

packages/react-client/src/forks/ReactFlightClientConfig.dom-browser.js

@@ -10,3 +10,4 @@
 export * from 'react-client/src/ReactFlightClientConfigBrowser';
 export * from 'react-server-dom-webpack/src/ReactFlightClientConfigWebpackBundler';
 export * from 'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';
+export const usedWithSSR = false;

packages/react-client/src/forks/ReactFlightClientConfig.dom-bun.js

@@ -20,3 +20,4 @@ export const resolveClientReference: any = null;
 export const resolveServerReference: any = null;
 export const preloadModule: any = null;
 export const requireModule: any = null;
+export const usedWithSSR = true;

packages/react-client/src/forks/ReactFlightClientConfig.dom-edge-webpack.js

@@ -10,3 +10,4 @@
 export * from 'react-client/src/ReactFlightClientConfigBrowser';
 export * from 'react-server-dom-webpack/src/ReactFlightClientConfigWebpackBundler';
 export * from 'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';
+export const usedWithSSR = true;

packages/react-client/src/forks/ReactFlightClientConfig.dom-legacy.js

@@ -10,3 +10,4 @@
 export * from 'react-client/src/ReactFlightClientConfigBrowser';
 export * from 'react-server-dom-webpack/src/ReactFlightClientConfigWebpackBundler';
 export * from 'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';
+export const usedWithSSR = true;

packages/react-client/src/forks/ReactFlightClientConfig.dom-node-esm.js

@@ -11,3 +11,4 @@
 export * from 'react-client/src/ReactFlightClientConfigBrowser';
 export * from 'react-server-dom-esm/src/ReactFlightClientConfigESMBundler';
 export * from 'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';
+export const usedWithSSR = true;

packages/react-client/src/forks/ReactFlightClientConfig.dom-node-webpack.js

@@ -10,3 +10,4 @@
 export * from 'react-client/src/ReactFlightClientConfigNode';
 export * from 'react-server-dom-webpack/src/ReactFlightClientConfigWebpackBundler';
 export * from 'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';
+export const usedWithSSR = true;

packages/react-client/src/forks/ReactFlightClientConfig.dom-node.js

@@ -10,3 +10,4 @@
 export * from 'react-client/src/ReactFlightClientConfigNode';
 export * from 'react-server-dom-webpack/src/ReactFlightClientConfigNodeBundler';
 export * from 'react-dom-bindings/src/shared/ReactFlightClientConfigDOM';
+export const usedWithSSR = true;