core-api: fix type inference of createRouteRef

packages/core-api/src/routing/RouteRef.ts

@@ -14,7 +14,16 @@
  * limitations under the License.
  */
 
-import { RouteRefConfig, RouteRef } from './types';
+import { RouteRef } from './types';
+import { IconComponent } from '../icons';
+
+export type RouteRefConfig<Params extends { [param in string]: string }> = {
+  params?: Array<keyof Params>;
+  /** @deprecated Route refs no longer decide their own path */
+  path?: string;
+  icon?: IconComponent;
+  title: string;
+};
 
 export class AbsoluteRouteRef<Params extends { [param in string]: string }> {
   constructor(private readonly config: RouteRefConfig<Params>) {}
@@ -38,9 +47,15 @@ export class AbsoluteRouteRef<Params extends { [param in string]: string }> {
 }
 
 export function createRouteRef<
-  ParamKeys extends string,
-  Params extends { [param in string]: string } = { [name in ParamKeys]: string }
->(config: RouteRefConfig<Params>): RouteRef<Params> {
+  Params extends { [param in ParamKey]: string },
+  ParamKey extends string = never
+>(config: {
+  params?: ParamKey[];
+  /** @deprecated Route refs no longer decide their own path */
+  path?: string;
+  icon?: IconComponent;
+  title: string;
+}): RouteRef<Params> {
   return new AbsoluteRouteRef<Params>(config);
 }
 

packages/core-api/src/routing/hooks.test.tsx

@@ -39,8 +39,9 @@ import {
   createRouteRef,
   createExternalRouteRef,
   ExternalRouteRef,
+  RouteRefConfig,
 } from './RouteRef';
-import { RouteRef, RouteRefConfig } from './types';
+import { RouteRef } from './types';
 
 const mockConfig = (extra?: Partial<RouteRefConfig<{}>>) => ({
   path: '/unused',

packages/core-api/src/routing/index.ts

@@ -16,11 +16,11 @@
 
 export type {
   RouteRef,
-  RouteRefConfig,
   AbsoluteRouteRef,
   ConcreteRoute,
   MutableRouteRef,
 } from './types';
 export { FlatRoutes } from './FlatRoutes';
 export { createRouteRef } from './RouteRef';
+export type { RouteRefConfig } from './RouteRef';
 export { useRouteRef } from './hooks';

packages/core-api/src/routing/types.ts

@@ -45,14 +45,6 @@ export type AbsoluteRouteRef = RouteRef<{}>;
  */
 export type MutableRouteRef = RouteRef<{}>;
 
-export type RouteRefConfig<Params extends { [param in string]: string }> = {
-  params?: Array<keyof Params>;
-  /** @deprecated Route refs no longer decide their own path */
-  path?: string;
-  icon?: IconComponent;
-  title: string;
-};
-
 // A duplicate of the react-router RouteObject, but with routeRef added
 export interface BackstageRouteObject {
   caseSensitive: boolean;