feat(router): add ParamMap.keys to get a list of parameters

packages/router/src/index.ts

@@ -20,7 +20,7 @@ export {ExtraOptions, ROUTER_CONFIGURATION, ROUTER_INITIALIZER, RouterModule, pr
 export {RouterOutletMap} from './router_outlet_map';
 export {NoPreloading, PreloadAllModules, PreloadingStrategy, RouterPreloader} from './router_preloader';
 export {ActivatedRoute, ActivatedRouteSnapshot, RouterState, RouterStateSnapshot} from './router_state';
-export {PRIMARY_OUTLET, ParamMap, Params} from './shared';
+export {PRIMARY_OUTLET, ParamMap, Params, convertToParamMap} from './shared';
 export {UrlHandlingStrategy} from './url_handling_strategy';
 export {DefaultUrlSerializer, UrlSegment, UrlSegmentGroup, UrlSerializer, UrlTree} from './url_tree';
 export {VERSION} from './version';

packages/router/src/shared.ts

@@ -54,6 +54,9 @@ export interface ParamMap {
    * If there is no such parameter, an empty array is returned.
    */
   getAll(name: string): string[];
+
+  /** Name of the parameters */
+  readonly keys: string[];
 }
 
 class ParamsAsMap implements ParamMap {
@@ -80,8 +83,15 @@ class ParamsAsMap implements ParamMap {
 
     return [];
   }
+
+  get keys(): string[] { return Object.keys(this.params); }
 }
 
+/**
+ * Convert a {@link Params} instance to a {@link ParamMap}.
+ *
+ * @stable
+ */
 export function convertToParamMap(params: Params): ParamMap {
   return new ParamsAsMap(params);
 }

packages/router/test/shared.spec.ts

@@ -16,6 +16,11 @@ describe('ParamsMap', () => {
     expect(map.has('not here')).toEqual(false);
   });
 
+  it('should returns the name of the parameters', () => {
+    const map = convertToParamMap({single: 's', multiple: ['m1', 'm2']});
+    expect(map.keys).toEqual(['single', 'multiple']);
+  });
+
   it('should support single valued parameters', () => {
     const map = convertToParamMap({single: 's', multiple: ['m1', 'm2']});
     expect(map.get('single')).toEqual('s');

tools/public_api_guard/router/router.d.ts

@@ -59,6 +59,9 @@ export interface CanLoad {
     canLoad(route: Route): Observable<boolean> | Promise<boolean> | boolean;
 }
 
+/** @stable */
+export declare function convertToParamMap(params: Params): ParamMap;
+
 /** @stable */
 export declare type Data = {
     [name: string]: any;
@@ -156,6 +159,7 @@ export declare class NoPreloading implements PreloadingStrategy {
 
 /** @stable */
 export interface ParamMap {
+    readonly keys: string[];
     get(name: string): string | null;
     getAll(name: string): string[];
     has(name: string): boolean;