typegen: headers (#12318)

Author: pcattori

packages/react-router-dev/typegen/generate.ts

@@ -55,6 +55,9 @@ export function generate(ctx: Context, route: RouteManifestEntry): string {
       export type MetaDescriptors = T.MetaDescriptors
       export type MetaFunction = (args: MetaArgs) => MetaDescriptors
 
+      export type HeadersArgs = T.HeadersArgs
+      export type HeadersFunction = (args: HeadersArgs) => Headers | HeadersInit
+
       export type LoaderArgs = T.CreateServerLoaderArgs<Info>
       export type ClientLoaderArgs = T.CreateClientLoaderArgs<Info>
       export type ActionArgs = T.CreateServerActionArgs<Info>

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

@@ -10,6 +10,7 @@ type IsDefined<T> = Equal<T, undefined> extends true ? false : true;
 type RouteModule = {
   meta?: Func;
   links?: Func;
+  headers?: Func;
   loader?: Func;
   clientLoader?: Func;
   action?: Func;
@@ -58,6 +59,13 @@ export type CreateMetaArgs<T extends RouteInfo> = {
 };
 export type MetaDescriptors = MetaDescriptor[];
 
+export type HeadersArgs = {
+  loaderHeaders: Headers;
+  parentHeaders: Headers;
+  actionHeaders: Headers;
+  errorHeaders: Headers | undefined;
+};
+
 // prettier-ignore
 type IsHydrate<ClientLoader> =
   ClientLoader extends { hydrate: true } ? true :