enhance thrown redirects on the client

Author: jacob-ebey

packages/react-router/lib/hooks.tsx

@@ -1090,7 +1090,7 @@ export class RenderErrorBoundary extends React.Component<
   }
 }
 
-const errorRedirectHandledMap = new WeakMap<any, boolean>();
+const errorRedirectHandledMap = new WeakMap<any, Promise<void>>();
 function RSCErrorHandler({
   children,
   error,
@@ -1099,7 +1099,6 @@ function RSCErrorHandler({
   error: unknown;
 }) {
   let { basename } = React.useContext(NavigationContext);
-  let navigate = useNavigate();
 
   if (
     typeof error === "object" &&
@@ -1109,22 +1108,25 @@ function RSCErrorHandler({
   ) {
     let redirect = decodeRedirectErrorDigest(error.digest);
     if (redirect) {
+      let existingRedirect = errorRedirectHandledMap.get(error);
+      if (existingRedirect) throw existingRedirect;
+
       let parsed = parseToInfo(redirect.location, basename);
 
       if (isBrowser && !errorRedirectHandledMap.get(error)) {
-        errorRedirectHandledMap.set(error, true);
-
         if (parsed.isExternal || redirect.reloadDocument) {
           window.location.href = parsed.absoluteURL || parsed.to;
         } else {
-          // @ts-expect-error - Needs React 19 types
-          React.startTransition(() => {
-            return navigate(parsed.to, {
+          const redirectPromise: Promise<void> = Promise.resolve().then(() =>
+            window.__reactRouterDataRouter!.navigate(parsed.to, {
               replace: redirect.replace,
-            });
-          });
+            }),
+          );
+          errorRedirectHandledMap.set(error, redirectPromise);
+          throw redirectPromise;
         }
       }
+
       return (
         <meta
           httpEquiv="refresh"

playground/rsc-vite/src/routes.ts

@@ -16,6 +16,11 @@ export const routes = [
         path: "about",
         lazy: () => import("./routes/about/about"),
       },
+      {
+        id: "render-redirect",
+        path: "render-redirect/:id?",
+        lazy: () => import("./routes/render-redirects"),
+      },
       {
         id: "parent",
         path: "parent",

playground/rsc-vite/src/routes/render-redirects.tsx

@@ -0,0 +1,23 @@
+import { Link, redirect } from "react-router";
+
+export default function RenderRedirect({
+  params: { id },
+}: {
+  params: { id?: string };
+}) {
+  if (id === "redirect") {
+    throw redirect("/render-redirect/redirected");
+  }
+
+  if (id === "external") {
+    throw redirect("https://example.com/");
+  }
+
+  return (
+    <>
+      <h1>{id || "home"}</h1>
+      <Link to="/render-redirect/redirect">Redirect</Link>
+      <Link to="/render-redirect/external">External</Link>
+    </>
+  );
+}