Allow redirects to be returned from client side middleware (#14598)

Author: brophdawg11

.changeset/strong-penguins-retire.md

@@ -0,0 +1,5 @@
+---
+"react-router": patch
+---
+
+Allow redirects to be returned from client side middleware

packages/react-router/__tests__/router/context-middleware-test.tsx

@@ -1684,6 +1684,110 @@ describe("context/middleware", () => {
         });
       });
     });
+
+    describe("redirects", () => {
+      it("allows you to return redirects before next from client middleware", async () => {
+        router = createRouter({
+          history: createMemoryHistory(),
+          routes: [
+            {
+              path: "/",
+            },
+            {
+              path: "/redirect",
+              middleware: [
+                async () => {
+                  return redirect("/target");
+                },
+              ],
+            },
+            {
+              path: "/target",
+            },
+          ],
+        });
+
+        await router.navigate("/redirect");
+        expect(router.state.location.pathname).toBe("/target");
+      });
+
+      it("allows you to return redirects after next from client middleware", async () => {
+        router = createRouter({
+          history: createMemoryHistory(),
+          routes: [
+            {
+              path: "/",
+            },
+            {
+              path: "/redirect",
+              middleware: [
+                async (_, next) => {
+                  await next();
+                  return redirect("/target");
+                },
+              ],
+            },
+            {
+              path: "/target",
+            },
+          ],
+        });
+
+        await router.navigate("/redirect");
+        expect(router.state.location.pathname).toBe("/target");
+      });
+
+      it("allows you to throw  redirects before next from client middleware", async () => {
+        router = createRouter({
+          history: createMemoryHistory(),
+          routes: [
+            {
+              path: "/",
+            },
+            {
+              path: "/redirect",
+              middleware: [
+                async () => {
+                  throw redirect("/target");
+                },
+              ],
+            },
+            {
+              path: "/target",
+            },
+          ],
+        });
+
+        await router.navigate("/redirect");
+        expect(router.state.location.pathname).toBe("/target");
+      });
+
+      it("allows you to throw redirects after next from client middleware", async () => {
+        router = createRouter({
+          history: createMemoryHistory(),
+          routes: [
+            {
+              path: "/",
+            },
+            {
+              path: "/redirect",
+              middleware: [
+                async (_, next) => {
+                  await next();
+                  throw redirect("/target");
+                },
+              ],
+            },
+            {
+              path: "/target",
+            },
+          ],
+        });
+
+        await router.navigate("/redirect");
+        expect(router.state.location.pathname).toBe("/target");
+      });
+    });
   });
 
   describe("middleware - handler.query", () => {

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

@@ -5664,7 +5664,13 @@ function runClientMiddlewarePipeline(
   return runMiddlewarePipeline(
     args,
     handler,
-    (r) => r, // No post-processing needed on the client
+    (r) => {
+      // Throw any redirect responses to short circuit
+      if (isRedirectResponse(r)) {
+        throw r;
+      }
+      return r;
+    },
     isDataStrategyResults,
     errorHandler,
   );