fix(router): accept a redirect function in RedirectRouteMeta

`RedirectRouteMeta.redirectTo` was typed `string`, so a `RouteMeta`
could not hold the `RedirectFunction` that Angular's `Route` accepts
and that `toRouteConfig` passes through unchanged. It now takes
Angular's `Route['redirectTo']` without `undefined`, and the typed
route helpers exclude redirect metas by the same shape.

The runtime checks that decide whether a page is a redirect test for a
nullish `redirectTo` instead of a falsy one, so `toRouteConfig`, the
route builder's dev warning and the route diagnostics share one rule.

Author: byrondover

packages/router/src/lib/models.ts

@@ -76,7 +76,7 @@ export interface DefaultRouteMeta<
 }
 
 export interface RedirectRouteMeta {
-  redirectTo: string;
+  redirectTo: NonNullable<Route['redirectTo']>;
   pathMatch?: Route['pathMatch'];
 }
 

packages/router/src/lib/route-builder.ts

@@ -243,7 +243,7 @@ function toRoutes<TFile>(
             module!().then((m) => {
               if (import.meta.env.DEV) {
                 const hasModuleDefault = !!m.default;
-                const hasRedirect = !!m.routeMeta?.redirectTo;
+                const hasRedirect = m.routeMeta?.redirectTo != null;
 
                 if (!hasModuleDefault && !hasRedirect) {
                   console.warn(

packages/router/src/lib/route-config.spec.ts

@@ -1,10 +1,14 @@
 import { provideHttpClient, withInterceptors } from '@angular/common/http';
 import { PLATFORM_ID, TransferState } from '@angular/core';
 import { TestBed } from '@angular/core/testing';
-import type { ActivatedRouteSnapshot } from '@angular/router';
+import type {
+  ActivatedRouteSnapshot,
+  PartialMatchRouteSnapshot,
+} from '@angular/router';
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
 import { API_PREFIX, BASE_URL, INTERNAL_FETCH } from '../../tokens/src';
+import type { RouteMeta } from './models';
 import { toRouteConfig } from './route-config';
 import { ANALOG_META_KEY, ANALOG_PAGE_ENDPOINTS } from './endpoints';
 import { requestContextInterceptor } from './request-context';
@@ -23,6 +27,23 @@ describe('toRouteConfig', () => {
     expect(config.redirectTo).toBe('/home');
   });
 
+  it('returns a redirect function config unchanged', () => {
+    const redirectTo = ({ params }: PartialMatchRouteSnapshot) =>
+      `/users/${params['id']}`;
+    const meta: RouteMeta = { redirectTo, pathMatch: 'full' };
+    const config = toRouteConfig(meta);
+
+    expect(config.redirectTo).toBe(redirectTo);
+    expect(config.pathMatch).toBe('full');
+  });
+
+  it('keeps redirectTo off non-redirect metas', () => {
+    // @ts-expect-error redirectTo belongs to redirect routes only
+    const meta: RouteMeta = { title: 'Users', redirectTo: '/users' };
+
+    expect(toRouteConfig(meta).redirectTo).toBe('/users');
+  });
+
   // Regression: content routes (from .md files in the pages directory) are
   // built by route-builder.ts WITHOUT setting ANALOG_META_KEY on the route
   // config — only page routes (.page.ts) get the symbol.  The `load`

packages/router/src/lib/route-config.ts

@@ -75,5 +75,5 @@ export function toRouteConfig(
 function isRedirectRouteMeta(
   routeMeta: RouteMeta<never>,
 ): routeMeta is RedirectRouteMeta {
-  return !!routeMeta.redirectTo;
+  return routeMeta.redirectTo != null;
 }

packages/router/src/lib/to-route.ts

@@ -184,7 +184,12 @@ type InheritedRouteData<Metas, Data = EmptyObject> = Metas extends [
 ]
   ? InheritedRouteData<
       Rest,
-      Merge<Data, RouteMetaData<Exclude<Meta, { redirectTo: string }>>>
+      Merge<
+        Data,
+        RouteMetaData<
+          Exclude<Meta, { redirectTo: NonNullable<Route['redirectTo']> }>
+        >
+      >
     >
   : Data;
 
@@ -203,7 +208,12 @@ type InheritedRouteResources<Metas, Resources = EmptyObject> = Metas extends [
 ]
   ? InheritedRouteResources<
       Rest,
-      Merge<Resources, RouteResourceMap<Exclude<Meta, { redirectTo: string }>>>
+      Merge<
+        Resources,
+        RouteResourceMap<
+          Exclude<Meta, { redirectTo: NonNullable<Route['redirectTo']> }>
+        >
+      >
     >
   : Resources;