fix: Add data request handler for non-existent routes

deno.json

@@ -153,7 +153,7 @@
   },
   "imports": {
     "react": "npm:react@^19.2.4",
-    "@types/react": "npm:@types/react@^19.2.9"
+    "@types/react": "npm:@types/react@^19.2.13"
   },
   "compilerOptions": {
     "lib": [

example/deno.json

@@ -36,19 +36,19 @@
     "@udibo/juniper": "jsr:@udibo/juniper@^0.3.2",
     "@udibo/esbuild-plugin-postcss": "jsr:@udibo/esbuild-plugin-postcss@^0.3.0",
     "@std/testing": "jsr:@std/testing@^1.0.17",
-    "@std/assert": "jsr:@std/assert@^1.0.17",
-    "@std/async": "jsr:@std/async@^1.1.0",
-    "@std/collections": "jsr:@std/collections@^1.1.4",
+    "@std/assert": "jsr:@std/assert@^1.0.18",
+    "@std/async": "jsr:@std/async@^1.1.1",
+    "@std/collections": "jsr:@std/collections@^1.1.5",
     "@std/encoding": "jsr:@std/encoding@^1.0.10",
     "@std/path": "jsr:@std/path@^1.1.4",
     "@std/streams": "jsr:@std/streams@^1.0.17",
     "@std/uuid": "jsr:@std/uuid@^1.1.0",
     "@opentelemetry/api": "npm:@opentelemetry/api@^1.9.0",
-    "playwright": "npm:playwright@^1.58.0",
+    "playwright": "npm:playwright@^1.58.2",
     "react": "npm:react@^19.2.4",
-    "@types/react": "npm:@types/react@^19.2.9",
+    "@types/react": "npm:@types/react@^19.2.13",
     "react-router": "npm:react-router@^7.13.0",
-    "hono": "npm:hono@^4.11.6",
+    "hono": "npm:hono@^4.11.9",
     "tailwindcss": "npm:tailwindcss@^4.1.18",
     "@tailwindcss/postcss": "npm:@tailwindcss/postcss@^4.1.18",
     "zod": "npm:zod@^4.3.6",

src/_server.tsx

@@ -5,7 +5,7 @@ import { parseArgs } from "@std/cli/parse-args";
 import { HttpError } from "./mod.ts";
 import { SpanStatusCode } from "@opentelemetry/api";
 import { Hono } from "hono";
-import type { Context, Env, Schema } from "hono";
+import type { Context, Env, MiddlewareHandler, Schema } from "hono";
 import { createFactory } from "hono/factory";
 import { serveStatic } from "hono/deno";
 import { stream } from "hono/streaming";
@@ -1047,6 +1047,20 @@ export function buildApp<
     app.route("*", catchallApp);
   }
 
+  // Catch data requests that didn't match any route handler at this level.
+  // This happens when the client navigates to a non-existent URL and React Router
+  // needs to re-fetch parent route data (e.g., GET /identity/applications with
+  // X-Juniper-Route-Id: "/" to refresh the root loader).
+  if (isClientRoute && errorHandler) {
+    const handleDataRequest = reactHandlers[reactHandlers.length - 1];
+    app.use("*", (c, next) => {
+      if (c.req.header("X-Juniper-Route-Id")) {
+        return (handleDataRequest as unknown as MiddlewareHandler)(c, next);
+      }
+      return next();
+    });
+  }
+
   app.use("*", notFound);
   return app;
 }