fix _root.data fetch when basename is set

Author: Aleuck

contributors.yml

@@ -16,6 +16,7 @@
 - akamfoad
 - alany411
 - alberto
+- Aleuck
 - alexandernanberg
 - alexanderson1993
 - alexlbr

packages/react-router/__tests__/dom/ssr/single-fetch-test.ts

@@ -0,0 +1,24 @@
+import { singleFetchUrl } from "../../../lib/dom/ssr/single-fetch";
+
+describe("singleFetchUrl", () => {
+  it("should resolve to _root.data when path is /", () => {
+    window.__reactRouterContext = {} as any;
+    const actual = singleFetchUrl(`${window.location.origin}/`);
+    expect(actual.toString()).toBe(`${window.location.origin}/_root.data`);
+  });
+
+  it("should resolve to _root.data when path is equal to basename", () => {
+    window.__reactRouterContext = {} as any;
+    window.__reactRouterContext!.basename = "/basename/";
+    const actual = singleFetchUrl(`${window.location.origin}/basename/`);
+    expect(actual.toString()).toBe(
+      `${window.location.origin}/basename/_root.data`
+    );
+  });
+
+  it("should resolve to path.data when path is not to base", () => {
+    window.__reactRouterContext = {} as any;
+    const actual = singleFetchUrl(`${window.location.origin}/path/`);
+    expect(actual.toString()).toBe(`${window.location.origin}/path.data`);
+  });
+});

packages/react-router/lib/dom/ssr/single-fetch.tsx

@@ -444,6 +444,10 @@ function stripIndexParam(url: URL) {
 }
 
 export function singleFetchUrl(reqUrl: URL | string) {
+  let basename =
+    (typeof window !== "undefined" && window.__reactRouterContext?.basename) ||
+    "";
+  basename = `/${basename}/`.replace(/\/+/g, "/");
   let url =
     typeof reqUrl === "string"
       ? new URL(
@@ -456,8 +460,8 @@ export function singleFetchUrl(reqUrl: URL | string) {
         )
       : reqUrl;
 
-  if (url.pathname === "/") {
-    url.pathname = "_root.data";
+  if (url.pathname === basename) {
+    url.pathname = `${basename}_root.data`;
   } else {
     url.pathname = `${url.pathname.replace(/\/$/, "")}.data`;
   }

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

@@ -107,9 +107,10 @@ export const createRequestHandler: CreateRequestHandlerFunction = (
     }
 
     let url = new URL(request.url);
+    let basebane = `/${_build.basename || ''}/`.replace(/\/+/g,'/')
     let normalizedPath = url.pathname
       .replace(/\.data$/, "")
-      .replace(/^\/_root$/, "/");
+      .replace(new RegExp(`^${basebane}_root$`), basebane);
     if (normalizedPath !== "/" && normalizedPath.endsWith("/")) {
       normalizedPath = normalizedPath.slice(0, -1);
     }