release: typegen fixes (#12443)

* typegen current route info into `matches`

* child matches may be undefined

.changeset/red-eagles-stare.md

@@ -3,8 +3,8 @@
 "react-router": patch
 ---
 
-Generate wide `matches` and `params` types for child routes
+Generate wide `matches` and `params` types for current route and child routes
 
 At runtime, `matches` includes child route matches and `params` include child route path parameters.
-But previously, we only generated types for parent routes and the current route in `matches` and `params`.
+But previously, we only generated types for parent routes in `matches`; for `params`, we only considered the parent routes and the current route.
 To align our generated types more closely to the runtime behavior, we now generate more permissive, wider types when accessing child route information.

integration/typegen-test.ts

@@ -282,15 +282,25 @@ test.describe("typegen", () => {
         import { Expect, Equal } from "../expect-type"
         import type { Route } from "./+types/current"
 
+        export function loader() {
+          return { current: 3 }
+        }
+
         export function meta({ matches }: Route.MetaArgs) {
           const parent1 = matches[1]
           type Test1 = Expect<Equal<typeof parent1.data, { parent1: number }>>
 
           const parent2 = matches[2]
           type Test2 = Expect<Equal<typeof parent2.data, { parent2: number }>>
 
+          const current = matches[3]
+          type Test3 = Expect<Equal<typeof current.data, { current: number }>>
+
           const child1 = matches[4]
-          type Test3 = Expect<Equal<typeof child1.data, unknown>>
+          type Test4a = Expect<undefined extends typeof child1 ? true : false>
+          if (child1) {
+            type Test4b = Expect<Equal<typeof child1.data, unknown>>
+          }
           return []
         }
 
@@ -301,8 +311,14 @@ test.describe("typegen", () => {
           const parent2 = matches[2]
           type Test2 = Expect<Equal<typeof parent2.data, { parent2: number }>>
 
+          const current = matches[3]
+          type Test3 = Expect<Equal<typeof current.data, { current: number }>>
+
           const child1 = matches[4]
-          type Test3 = Expect<Equal<typeof child1.data, unknown>>
+          type Test4a = Expect<undefined extends typeof child1 ? true : false>
+          if (child1) {
+            type Test4b = Expect<Equal<typeof child1.data, unknown>>
+          }
         }
       `,
     });

packages/react-router/lib/types/route-module.ts

@@ -48,14 +48,14 @@ type MetaMatch<T extends RouteInfo> = Pretty<
 type MetaMatches<T extends RouteInfo[]> =
   T extends [infer F extends RouteInfo, ...infer R extends RouteInfo[]]
     ? [MetaMatch<F>, ...MetaMatches<R>]
-    : MetaMatch<RouteInfo>[];
+    : Array<MetaMatch<RouteInfo> | undefined>;
 
 export type CreateMetaArgs<T extends RouteInfo> = {
   location: Location;
   params: T["params"];
   data: T["loaderData"];
   error?: unknown;
-  matches: MetaMatches<T["parents"]>;
+  matches: MetaMatches<[...T["parents"], T]>;
 };
 export type MetaDescriptors = MetaDescriptor[];
 
@@ -149,13 +149,13 @@ type Match<T extends RouteInfo> = Pretty<
 type Matches<T extends RouteInfo[]> =
   T extends [infer F extends RouteInfo, ...infer R extends RouteInfo[]]
     ? [Match<F>, ...Matches<R>]
-    : Match<RouteInfo>[];
+    : Array<Match<RouteInfo> | undefined>;
 
 export type CreateComponentProps<T extends RouteInfo> = {
   params: T["params"];
   loaderData: T["loaderData"];
   actionData?: T["actionData"];
-  matches: Matches<T["parents"]>;
+  matches: Matches<[...T["parents"], T]>;
 };
 
 export type CreateErrorBoundaryProps<T extends RouteInfo> = {