ffguard.ts

@Injectable({ providedIn: 'root' })
export class FeatureFlagGuard implements CanActivate {
  constructor(private userQuery: UserQuery) {
  }

  canActivate(route: ActivatedRouteSnapshot): boolean {
    return this.userQuery.hasFlags(route.data.flags);
  }
}

routes.ts

const routes: Routes = [
  ...
  {
    path: '...',
    component: ProtectedComponent,
    canActivate: [FeatureFlagGuard],
    data: {
      flags: 'b' // or ['a', 'b']
    }
  }
];