make config service not required

src/lib/common-ui.module.ts

@@ -95,19 +95,33 @@ export class CommonUiModule extends ModuleWithOptions {
             options.existingUserPreferenceService,
         );
 
+        const configServiceProviders = this._getConfigServiceProviders(options.configServiceFactory, options.configService);
+
         return {
             ngModule: CommonUiModule,
-            providers: [
-                userPreferenceService,
+            providers: [userPreferenceService, configServiceProviders],
+        };
+    }
+
+    private static _getConfigServiceProviders(configServiceFactory: () => unknown, configService: unknown) {
+        if (configService) {
+            return [
                 {
-                    provide: options.configService,
-                    useFactory: options.configServiceFactory,
+                    provide: configService,
+                    useFactory: configServiceFactory,
                 },
                 {
                     provide: BaseConfigService,
-                    useExisting: options.configService,
+                    useExisting: configService,
                 },
-            ],
-        };
+            ];
+        }
+
+        return [
+            {
+                provide: BaseConfigService,
+                useFactory: configServiceFactory,
+            },
+        ];
     }
 }

src/lib/utils/types/common-ui-options.ts

@@ -8,6 +8,6 @@ export interface CommonUiOptions<
     AppConfig extends BaseAppConfig,
 > {
     existingUserPreferenceService?: Type<UserPreference>;
-    configService: Type<Config>;
+    configService?: Type<Config>;
     configServiceFactory: () => Config;
 }