bug: fixing issue with type inference for ParamKeys

Signed-off-by: blam <ben@blam.sh>

packages/core-plugin-api/report.api.md

@@ -613,9 +613,13 @@ export type OptionalParams<
 > = Params[keyof Params] extends never ? undefined : Params;
 
 // @public @deprecated
-export type ParamKeys<Params extends AnyParams> = keyof Params extends never
+export type ParamKeys<Params extends AnyParams> = [AnyRouteRefParams] extends [
+  Params,
+]
+  ? string[]
+  : keyof Params extends never
   ? []
-  : (keyof Params)[];
+  : Array<keyof Params>;
 
 // @public @deprecated
 export type ParamNames<S extends string> =

packages/core-plugin-api/src/routing/ExternalRouteRef.test.ts

@@ -87,7 +87,7 @@ describe('ExternalRouteRef', () => {
     const _3 = createExternalRouteRef({ id: '3', params: ['x', 'y'] });
     // @ts-expect-error
     validateType<{ x: string }, any>(_3);
-    // extra z, we validate this at runtime instead
+    // @ts-expect-error
     validateType<{ x: string; y: string; z: string }, any>(_3);
     validateType<{ x: string; y: string }, false>(_3);
 

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

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { AnyParams, RouteRef } from './types';
+import { AnyParams, RouteRef, ParamKeys } from './types';
 import { createRouteRef } from './RouteRef';
 
 describe('RouteRef', () => {
@@ -54,7 +54,7 @@ describe('RouteRef', () => {
     validateType<undefined>(_2);
     // @ts-expect-error
     validateType<{ x: string; z: string }>(_2);
-    // extra z, we validate this at runtime instead
+    // @ts-expect-error
     validateType<{ x: string; y: string; z: string }>(_2);
     validateType<{ x: string; y: string }>(_2);
 
@@ -71,4 +71,30 @@ describe('RouteRef', () => {
     // To avoid complains about missing expectations and unused vars
     expect([_1, _2, _3, _4].join('')).toEqual(expect.any(String));
   });
+
+  it('should properly infer param keys', () => {
+    function validateType<T>(_test: T) {}
+
+    validateType<ParamKeys<{ x: string; y: string }>>(['x', 'y']);
+
+    // @ts-expect-error
+    validateType<ParamKeys<{}>>(['asd']);
+    validateType<ParamKeys<{}>>([]);
+
+    // @ts-expect-error
+    validateType<ParamKeys<{ [key in string]: string }>>([1]);
+    validateType<ParamKeys<{ [key in string]: string }>>(['migrationId']);
+
+    // @ts-expect-error
+    validateType<ParamKeys<{ [key in string]: string } | undefined>>([1]);
+    validateType<ParamKeys<{ [key in string]: string } | undefined>>([
+      'migrationId',
+    ]);
+
+    // @ts-expect-error
+    validateType<ParamKeys<undefined>>(['asd']);
+    validateType<ParamKeys<undefined>>([]);
+
+    expect(true).toBeDefined();
+  });
 });

packages/core-plugin-api/src/routing/SubRouteRef.test.ts

@@ -102,7 +102,7 @@ describe('SubRouteRef', () => {
     validateType<{ x: string; z: string }>(_2);
     // @ts-expect-error
     validateType<{ y: string }>(_2);
-    // extra z, we validate this at runtime instead
+    // @ts-expect-error
     validateType<{ x: string; y: string; z: string }>(_2);
     validateType<{ x: string; y: string }>(_2);
 

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

@@ -35,9 +35,13 @@ export type AnyParams = AnyRouteRefParams;
  * @public
  * @deprecated this type is deprecated and will be removed in the future
  */
-export type ParamKeys<Params extends AnyParams> = keyof Params extends never
+export type ParamKeys<Params extends AnyParams> = [AnyRouteRefParams] extends [
+  Params,
+]
+  ? string[]
+  : keyof Params extends never
   ? []
-  : (keyof Params)[];
+  : Array<keyof Params>;
 
 /**
  * Optional route params.