Fix typegen for routes with a client loader but no server loader (#12117)

Author: brophdawg11

.changeset/little-cooks-pull.md

@@ -0,0 +1,5 @@
+---
+"react-router": patch
+---
+
+Fix typegen for routes with a client loader but no server loader

integration/vite-prerender-test.ts

@@ -1,5 +1,6 @@
 import fs from "node:fs";
 import path from "node:path";
+import { PassThrough } from "node:stream";
 import { test, expect } from "@playwright/test";
 
 import {
@@ -153,7 +154,9 @@ test.describe("Prerendering", () => {
   });
 
   test("Prerenders known static routes when true is specified", async () => {
+    let buildStdio = new PassThrough();
     fixture = await createFixture({
+      buildStdio,
       prerender: true,
       files: {
         ...files,
@@ -192,6 +195,26 @@ test.describe("Prerendering", () => {
         `,
       },
     });
+
+    let buildOutput: string;
+    let chunks: Buffer[] = [];
+    buildOutput = await new Promise<string>((resolve, reject) => {
+      buildStdio.on("data", (chunk) => chunks.push(Buffer.from(chunk)));
+      buildStdio.on("error", (err) => reject(err));
+      buildStdio.on("end", () =>
+        resolve(Buffer.concat(chunks).toString("utf8"))
+      );
+    });
+
+    expect(buildOutput).toContain(
+      [
+        "⚠️ Paths with dynamic/splat params cannot be prerendered when using `prerender: true`.",
+        "You may want to use the `prerender()` API to prerender the following paths:",
+        "  - :slug",
+        "  - *",
+      ].join("\n")
+    );
+
     appFixture = await createAppFixture(fixture);
 
     let clientDir = path.join(fixture.projectDir, "build", "client");

packages/react-router-dev/vite/plugin.ts

@@ -1897,12 +1897,13 @@ function determineStaticPrerenderRoutes(
   }
   recurse(routes);
 
-  if (isBooleanUsage && paramRoutes) {
+  if (isBooleanUsage && paramRoutes.length > 0) {
     viteConfig.logger.warn(
-      "The following paths were not prerendered because Dynamic Param and Splat " +
-        "routes cannot be prerendered when using `prerender:true`. You may want to " +
-        "consider using the `prerender()` API if you wish to prerender slug and " +
-        "splat routes."
+      [
+        "⚠️ Paths with dynamic/splat params cannot be prerendered when using `prerender: true`.",
+        "You may want to use the `prerender()` API to prerender the following paths:",
+        ...paramRoutes.map((p) => "  - " + p),
+      ].join("\n")
     );
   }
 

packages/react-router/lib/types.ts

@@ -66,15 +66,12 @@ type _CreateLoaderData<
   ClientLoaderHydrate extends boolean,
   HasHydrateFallback
 > =
-  [HasHydrateFallback, ClientLoaderHydrate]  extends [true, true] ?
+  [HasHydrateFallback, ClientLoaderHydrate] extends [true, true] ?
     IsDefined<ClientLoaderData> extends true ? ClientLoaderData :
     undefined
   :
   [IsDefined<ClientLoaderData>, IsDefined<ServerLoaderData>] extends [true, true] ? ServerLoaderData | ClientLoaderData :
-  IsDefined<ClientLoaderData> extends true ?
-    ClientLoaderHydrate extends true ? ClientLoaderData :
-    ClientLoaderData | undefined
-  :
+  IsDefined<ClientLoaderData> extends true ? ClientLoaderData :
   IsDefined<ServerLoaderData> extends true ? ServerLoaderData :
   undefined
 
@@ -221,7 +218,7 @@ type __tests = [
       CreateLoaderData<{
         clientLoader: () => { a: string; b: Date; c: () => boolean };
       }>,
-      undefined | { a: string; b: Date; c: () => boolean }
+      { a: string; b: Date; c: () => boolean }
     >
   >,
   Expect<