Implement alternate fix via ServerBuild type

Author: markdalgleish

.changeset/tiny-gifts-wash.md

@@ -1,5 +1,5 @@
 ---
-"@react-router/dev": patch
+"react-router": patch
 ---
 
-Update generated types for `virtual:react-router/server-build` to ensure compatibility with TypeScript's `exactOptionalPropertyTypes` option
+Update `ServerBuild` type to ensure compatibility with TypeScript's `exactOptionalPropertyTypes` option

integration/typegen-test.ts

@@ -490,7 +490,6 @@ test.describe("typegen", () => {
       expect(proc.status).toBe(0);
     });
 
-
     test("works with tsconfig 'exactOptionalPropertyTypes' set to 'true'", async () => {
       const cwd = await createProject({
         "vite.config.ts": viteConfig,

packages/react-router-dev/typegen/index.ts

@@ -152,18 +152,17 @@ function register(ctx: Context) {
 
 const virtual = ts`
   declare module "virtual:react-router/server-build" {
-    import type { ServerBuild } from "react-router";
-    // Whilst this uses the CommonJS 'export =' syntax, which is technically not
-    // ESM-compliant, it is intentionally implemented this way to properly support
-    // optional properties in the ServerBuild type.
-    //
-    // TypeScript's type system does not provide an elegant solution for defining
-    // optional exports at the module level in ESM syntax, so this approach offers
-    // the most accurate type definitions for maintainability.
-    //
-    // This ensures all properties of ServerBuild, including optional ones, are
-    // properly type-checked when using this module.
-    const serverBuild: ServerBuild;
-    export = serverBuild;
+    import type { ServerBuild } from "react-router";    import { ServerBuild } from "react-router";
+    export const assets: ServerBuild["assets"];
+    export const assetsBuildDirectory: ServerBuild["assetsBuildDirectory"];
+    export const basename: ServerBuild["basename"];
+    export const entry: ServerBuild["entry"];
+    export const future: ServerBuild["future"];
+    export const isSpaMode: ServerBuild["isSpaMode"];
+    export const prerender: ServerBuild["prerender"];
+    export const publicPath: ServerBuild["publicPath"];
+    export const routes: ServerBuild["routes"];
+    export const ssr: ServerBuild["ssr"];
+    export const unstable_getCriticalCss: ServerBuild["unstable_getCriticalCss"];
   }
 `;

packages/react-router/lib/server-runtime/build.ts

@@ -24,14 +24,20 @@ export interface ServerBuild {
   };
   routes: ServerRouteManifest;
   assets: AssetsManifest;
-  basename?: string;
+  // `| undefined` is required to ensure compatibility with TypeScript's
+  // `exactOptionalPropertyTypes` option
+  basename?: string | undefined;
   publicPath: string;
   assetsBuildDirectory: string;
   future: FutureConfig;
   ssr: boolean;
-  unstable_getCriticalCss?: (args: {
-    pathname: string;
-  }) => OptionalCriticalCss | Promise<OptionalCriticalCss>;
+  unstable_getCriticalCss?:
+    | ((args: {
+        pathname: string;
+      }) => OptionalCriticalCss | Promise<OptionalCriticalCss>)
+    // `| undefined` is required to ensure compatibility with TypeScript's
+    // `exactOptionalPropertyTypes` option
+    | undefined;
   /**
    * @deprecated This is now done via a custom header during prerendering
    */