feat: use result instead of either (#4724)

* feat: use result instead of either

* chore: remove dartz

frontend/appflowy_flutter/integration_test/util/common_operations.dart

@@ -306,7 +306,7 @@ extension CommonOperations on WidgetTester {
       KVKeys.showRenameDialogWhenCreatingNewFile,
       (value) => bool.parse(value),
     );
-    final showRenameDialog = settingsOrFailure.fold(() => false, (r) => r);
+    final showRenameDialog = settingsOrFailure ?? false;
     if (showRenameDialog) {
       await tapOKButton();
     }

frontend/appflowy_flutter/lib/core/config/kv.dart

@@ -1,10 +1,9 @@
-import 'package:dartz/dartz.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 abstract class KeyValueStorage {
   Future<void> set(String key, String value);
-  Future<Option<String>> get(String key);
+  Future<String?> get(String key);
-  Future<Option<T>> getWithFormat<T>(
+  Future<T?> getWithFormat<T>(
     String key,
     T Function(String value) formatter,
   );
@@ -17,26 +16,26 @@ class DartKeyValue implements KeyValueStorage {
   SharedPreferences get sharedPreferences => _sharedPreferences!;
 
   @override
-  Future<Option<String>> get(String key) async {
+  Future<String?> get(String key) async {
     await _initSharedPreferencesIfNeeded();
 
     final value = sharedPreferences.getString(key);
     if (value != null) {
-      return Some(value);
+      return value;
     }
-    return none();
+    return null;
   }
 
   @override
-  Future<Option<T>> getWithFormat<T>(
+  Future<T?> getWithFormat<T>(
     String key,
     T Function(String value) formatter,
   ) async {
     final value = await get(key);
-    return value.fold(
+    if (value == null) {
-      () => none(),
+      return null;
-      (s) => Some(formatter(s)),
+    }
-    );
+    return formatter(value);
   }
 
   @override

frontend/appflowy_flutter/lib/core/config/kv_keys.dart

@@ -49,7 +49,7 @@ class KVKeys {
 
   static const String kCloudType = 'kCloudType';
   static const String kAppflowyCloudBaseURL = 'kAppFlowyCloudBaseURL';
-  static const String kSupabaseURL = 'kSupbaseURL';
+  static const String kSupabaseURL = 'kSupabaseURL';
   static const String kSupabaseAnonKey = 'kSupabaseAnonKey';
 
   /// The key for saving the text scale factor.

frontend/appflowy_flutter/lib/core/helpers/helpers.dart

@@ -1,2 +1 @@
 export 'target_platform.dart';
-export 'url_validator.dart';

frontend/appflowy_flutter/lib/core/helpers/url_validator.dart

@@ -1,21 +0,0 @@
-import 'package:dartz/dartz.dart';
-import 'package:freezed_annotation/freezed_annotation.dart';
-part 'url_validator.freezed.dart';
-
-Either<UriFailure, Uri> parseValidUrl(String url) {
-  try {
-    final uri = Uri.parse(url);
-    if (uri.scheme.isEmpty || uri.host.isEmpty) {
-      return left(const UriFailure.invalidSchemeHost());
-    }
-    return right(uri);
-  } on FormatException {
-    return left(const UriFailure.invalidUriFormat());
-  }
-}
-
-@freezed
-class UriFailure with _$UriFailure {
-  const factory UriFailure.invalidSchemeHost() = _InvalidSchemeHost;
-  const factory UriFailure.invalidUriFormat() = _InvalidUriFormat;
-}

frontend/appflowy_flutter/lib/core/notification/document_notification.dart

@@ -3,11 +3,11 @@ import 'dart:typed_data';
 import 'package:appflowy/core/notification/notification_helper.dart';
 import 'package:appflowy_backend/protobuf/flowy-document/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 typedef DocumentNotificationCallback = void Function(
   DocumentNotification,
-  Either<Uint8List, FlowyError>,
+  FlowyResult<Uint8List, FlowyError>,
 );
 
 class DocumentNotificationParser

frontend/appflowy_flutter/lib/core/notification/folder_notification.dart

@@ -1,17 +1,18 @@
 import 'dart:async';
 import 'dart:typed_data';
-import 'package:appflowy_backend/protobuf/flowy-notification/protobuf.dart';
+
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/notification.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-notification/protobuf.dart';
 import 'package:appflowy_backend/rust_stream.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 import 'notification_helper.dart';
 
 // Folder
 typedef FolderNotificationCallback = void Function(
   FolderNotification,
-  Either<Uint8List, FlowyError>,
+  FlowyResult<Uint8List, FlowyError>,
 );
 
 class FolderNotificationParser
@@ -27,7 +28,7 @@ class FolderNotificationParser
 
 typedef FolderNotificationHandler = Function(
   FolderNotification ty,
-  Either<Uint8List, FlowyError> result,
+  FlowyResult<Uint8List, FlowyError> result,
 );
 
 class FolderNotificationListener {

frontend/appflowy_flutter/lib/core/notification/grid_notification.dart

@@ -1,17 +1,18 @@
 import 'dart:async';
 import 'dart:typed_data';
-import 'package:appflowy_backend/protobuf/flowy-notification/protobuf.dart';
+
-import 'package:dartz/dartz.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-notification/protobuf.dart';
 import 'package:appflowy_backend/rust_stream.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 import 'notification_helper.dart';
 
 // DatabasePB
 typedef DatabaseNotificationCallback = void Function(
   DatabaseNotification,
-  Either<Uint8List, FlowyError>,
+  FlowyResult<Uint8List, FlowyError>,
 );
 
 class DatabaseNotificationParser
@@ -27,7 +28,7 @@ class DatabaseNotificationParser
 
 typedef DatabaseNotificationHandler = Function(
   DatabaseNotification ty,
-  Either<Uint8List, FlowyError> result,
+  FlowyResult<Uint8List, FlowyError> result,
 );
 
 class DatabaseNotificationListener {

frontend/appflowy_flutter/lib/core/notification/notification_helper.dart

@@ -1,6 +1,7 @@
 import 'dart:typed_data';
+
 import 'package:appflowy_backend/protobuf/flowy-notification/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class NotificationParser<T, E> {
   NotificationParser({
@@ -11,7 +12,7 @@ class NotificationParser<T, E> {
   });
 
   String? id;
-  void Function(T, Either<Uint8List, E>) callback;
+  void Function(T, FlowyResult<Uint8List, E>) callback;
   E Function(Uint8List) errorParser;
   T? Function(int) tyParser;
 
@@ -30,10 +31,10 @@ class NotificationParser<T, E> {
     if (subject.hasError()) {
       final bytes = Uint8List.fromList(subject.error);
       final error = errorParser(bytes);
-      callback(ty, right(error));
+      callback(ty, FlowyResult.failure(error));
     } else {
       final bytes = Uint8List.fromList(subject.payload);
-      callback(ty, left(bytes));
+      callback(ty, FlowyResult.success(bytes));
     }
   }
 }

frontend/appflowy_flutter/lib/core/notification/user_notification.dart

@@ -1,17 +1,18 @@
 import 'dart:async';
 import 'dart:typed_data';
+
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-notification/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-user/protobuf.dart';
-import 'package:dartz/dartz.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/rust_stream.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 import 'notification_helper.dart';
 
 // User
 typedef UserNotificationCallback = void Function(
   UserNotification,
-  Either<Uint8List, FlowyError>,
+  FlowyResult<Uint8List, FlowyError>,
 );
 
 class UserNotificationParser
@@ -27,7 +28,7 @@ class UserNotificationParser
 
 typedef UserNotificationHandler = Function(
   UserNotification ty,
-  Either<Uint8List, FlowyError> result,
+  FlowyResult<Uint8List, FlowyError> result,
 );
 
 class UserNotificationListener {

frontend/appflowy_flutter/lib/date/date_service.dart

@@ -1,19 +1,25 @@
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-date/entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class DateService {
-  static Future<Either<FlowyError, DateTime>> queryDate(String search) async {
+  static Future<FlowyResult<DateTime, FlowyError>> queryDate(
+    String search,
+  ) async {
     final query = DateQueryPB.create()..query = search;
-    final result = (await DateEventQueryDate(query).send()).swap();
+    final result = await DateEventQueryDate(query).send();
-    return result.fold((l) => left(l), (r) {
+    return result.fold(
-      final date = DateTime.tryParse(r.date);
+      (s) {
+        final date = DateTime.tryParse(s.date);
         if (date != null) {
-        return right(date);
+          return FlowyResult.success(date);
         }
-
+        return FlowyResult.failure(
-      return left(FlowyError(msg: 'Could not parse Date (NLP) from String'));
+          FlowyError(msg: 'Could not parse Date (NLP) from String'),
-    });
+        );
+      },
+      (e) => FlowyResult.failure(e),
+    );
   }
 }

frontend/appflowy_flutter/lib/env/cloud_env.dart

@@ -4,7 +4,6 @@ import 'package:appflowy/env/backend_env.dart';
 import 'package:appflowy/env/env.dart';
 import 'package:appflowy/startup/startup.dart';
 import 'package:appflowy_backend/log.dart';
-import 'package:dartz/dartz.dart';
 
 /// Sets the cloud type for the application.
 ///
@@ -52,7 +51,7 @@ const String kAppflowyCloudUrl = "https://beta.appflowy.cloud";
 ///
 Future<AuthenticatorType> getAuthenticatorType() async {
   final value = await getIt<KeyValueStorage>().get(KVKeys.kCloudType);
-  if (value.isNone() && !integrationMode().isUnitTest) {
+  if (value == null && !integrationMode().isUnitTest) {
     // if the cloud type is not set, then set it to AppFlowy Cloud as default.
     await useAppFlowyBetaCloudWithURL(
       kAppflowyCloudUrl,
@@ -61,7 +60,7 @@ Future<AuthenticatorType> getAuthenticatorType() async {
     return AuthenticatorType.appflowyCloud;
   }
 
-  switch (value.getOrElse(() => "0")) {
+  switch (value ?? "0") {
     case "0":
       return AuthenticatorType.local;
     case "1":
@@ -177,16 +176,13 @@ AuthenticatorType currentCloudType() {
   return getIt<AppFlowyCloudSharedEnv>().authenticatorType;
 }
 
-Future<void> _setAppFlowyCloudUrl(Option<String> url) async {
+Future<void> _setAppFlowyCloudUrl(String? url) async {
-  await url.fold(
+  await getIt<KeyValueStorage>().set(KVKeys.kAppflowyCloudBaseURL, url ?? '');
-    () => getIt<KeyValueStorage>().set(KVKeys.kAppflowyCloudBaseURL, ""),
-    (s) => getIt<KeyValueStorage>().set(KVKeys.kAppflowyCloudBaseURL, s),
-  );
 }
 
 Future<void> useSelfHostedAppFlowyCloudWithURL(String url) async {
   await _setAuthenticatorType(AuthenticatorType.appflowyCloudSelfHost);
-  await _setAppFlowyCloudUrl(Some(url));
+  await _setAppFlowyCloudUrl(url);
 }
 
 Future<void> useAppFlowyBetaCloudWithURL(
@@ -194,7 +190,7 @@ Future<void> useAppFlowyBetaCloudWithURL(
   AuthenticatorType authenticatorType,
 ) async {
   await _setAuthenticatorType(authenticatorType);
-  await _setAppFlowyCloudUrl(Some(url));
+  await _setAppFlowyCloudUrl(url);
 }
 
 Future<void> useLocalServer() async {
@@ -206,7 +202,7 @@ Future<void> useSupabaseCloud({
   required String anonKey,
 }) async {
   await _setAuthenticatorType(AuthenticatorType.supabase);
-  await setSupbaseServer(Some(url), Some(anonKey));
+  await setSupabaseServer(url, anonKey);
 }
 
 /// Use getIt<AppFlowyCloudSharedEnv>() to get the shared environment.
@@ -314,10 +310,7 @@ Future<AppFlowyCloudConfiguration> getAppFlowyCloudConfig(
 Future<String> getAppFlowyCloudUrl() async {
   final result =
       await getIt<KeyValueStorage>().get(KVKeys.kAppflowyCloudBaseURL);
-  return result.fold(
+  return result ?? kAppflowyCloudUrl;
-    () => kAppflowyCloudUrl,
-    (url) => url,
-  );
 }
 
 Future<String> _getAppFlowyCloudWSUrl(String baseURL) async {
@@ -339,27 +332,30 @@ Future<String> _getAppFlowyCloudGotrueUrl(String baseURL) async {
   return "$baseURL/gotrue";
 }
 
-Future<void> setSupbaseServer(
+Future<void> setSupabaseServer(
-  Option<String> url,
+  String? url,
-  Option<String> anonKey,
+  String? anonKey,
 ) async {
   assert(
-    (url.isSome() && anonKey.isSome()) || (url.isNone() && anonKey.isNone()),
+    (url != null && anonKey != null) || (url == null && anonKey == null),
     "Either both Supabase URL and anon key must be set, or both should be unset",
   );
 
-  await url.fold(
+  if (url == null) {
-    () => getIt<KeyValueStorage>().remove(KVKeys.kSupabaseURL),
+    await getIt<KeyValueStorage>().remove(KVKeys.kSupabaseURL);
-    (s) => getIt<KeyValueStorage>().set(KVKeys.kSupabaseURL, s),
+  } else {
-  );
+    await getIt<KeyValueStorage>().set(KVKeys.kSupabaseURL, url);
-  await anonKey.fold(
+  }
-    () => getIt<KeyValueStorage>().remove(KVKeys.kSupabaseAnonKey),
+
-    (s) => getIt<KeyValueStorage>().set(KVKeys.kSupabaseAnonKey, s),
+  if (anonKey == null) {
-  );
+    await getIt<KeyValueStorage>().remove(KVKeys.kSupabaseAnonKey);
+  } else {
+    await getIt<KeyValueStorage>().set(KVKeys.kSupabaseAnonKey, anonKey);
+  }
 }
 
 Future<SupabaseConfiguration> getSupabaseCloudConfig() async {
-  final url = await _getSupbaseUrl();
+  final url = await _getSupabaseUrl();
   final anonKey = await _getSupabaseAnonKey();
   return SupabaseConfiguration(
     url: url,
@@ -367,18 +363,12 @@ Future<SupabaseConfiguration> getSupabaseCloudConfig() async {
   );
 }
 
-Future<String> _getSupbaseUrl() async {
+Future<String> _getSupabaseUrl() async {
   final result = await getIt<KeyValueStorage>().get(KVKeys.kSupabaseURL);
-  return result.fold(
+  return result ?? '';
-    () => "",
-    (url) => url,
-  );
 }
 
 Future<String> _getSupabaseAnonKey() async {
   final result = await getIt<KeyValueStorage>().get(KVKeys.kSupabaseAnonKey);
-  return result.fold(
+  return result ?? '';
-    () => "",
-    (url) => url,
-  );
 }

frontend/appflowy_flutter/lib/mobile/application/user_profile/user_profile_bloc.dart

@@ -31,8 +31,8 @@ class UserProfileBloc extends Bloc<UserProfileEvent, UserProfileState> {
     );
 
     final userProfile = userOrFailure.fold(
-      (error) => null,
       (userProfilePB) => userProfilePB,
+      (error) => null,
     );
 
     if (workspaceSetting == null || userProfile == null) {

frontend/appflowy_flutter/lib/mobile/presentation/base/mobile_view_page.dart

@@ -13,7 +13,7 @@ import 'package:appflowy/workspace/application/view/view_ext.dart';
 import 'package:appflowy/workspace/application/view/view_service.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
-import 'package:dartz/dartz.dart' hide State;
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
 import 'package:flutter/material.dart';
@@ -40,7 +40,7 @@ class MobileViewPage extends StatefulWidget {
 }
 
 class _MobileViewPageState extends State<MobileViewPage> {
-  late final Future<Either<ViewPB, FlowyError>> future;
+  late final Future<FlowyResult<ViewPB, FlowyError>> future;
 
   @override
   void initState() {

frontend/appflowy_flutter/lib/mobile/presentation/favorite/mobile_favorite_page.dart

@@ -35,10 +35,12 @@ class MobileFavoriteScreen extends StatelessWidget {
           },
           (error) => null,
         );
-        final userProfile =
+        final userProfile = snapshots.data?[1].fold(
-            snapshots.data?[1].fold((error) => null, (userProfilePB) {
+          (userProfilePB) {
             return userProfilePB as UserProfilePB?;
-        });
+          },
+          (error) => null,
+        );
 
         // In the unlikely case either of the above is null, eg.
         // when a workspace is already open this can happen.

frontend/appflowy_flutter/lib/mobile/presentation/home/mobile_home_page.dart

@@ -41,10 +41,12 @@ class MobileHomeScreen extends StatelessWidget {
           },
           (error) => null,
         );
-        final userProfile =
+        final userProfile = snapshots.data?[1].fold(
-            snapshots.data?[1].fold((error) => null, (userProfilePB) {
+          (userProfilePB) {
             return userProfilePB as UserProfilePB?;
-        });
+          },
+          (error) => null,
+        );
 
         // In the unlikely case either of the above is null, eg.
         // when a workspace is already open this can happen.

frontend/appflowy_flutter/lib/mobile/presentation/home/mobile_home_setting_page.dart

@@ -35,12 +35,15 @@ class _MobileHomeSettingPageState extends State<MobileHomeSettingPage> {
           return const Center(child: CircularProgressIndicator.adaptive());
         }
 
-        final userProfile = snapshot.data?.fold((error) {
+        final userProfile = snapshot.data?.fold(
+          (userProfile) {
+            return userProfile;
+          },
+          (error) {
             errorMsg = error.msg;
             return null;
-        }, (userProfile) {
+          },
-          return userProfile;
+        );
-        });
 
         return Scaffold(
           appBar: FlowyAppBar(

frontend/appflowy_flutter/lib/mobile/presentation/setting/user_session_setting_group.dart

@@ -5,6 +5,7 @@ import 'package:appflowy/user/application/auth/auth_service.dart';
 import 'package:appflowy/user/application/sign_in_bloc.dart';
 import 'package:appflowy/user/presentation/screens/sign_in_screen/widgets/sign_in_or_logout_button.dart';
 import 'package:appflowy/user/presentation/screens/sign_in_screen/widgets/widgets.dart';
+import 'package:appflowy_backend/log.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
 import 'package:flutter/material.dart';
@@ -27,12 +28,9 @@ class UserSessionSettingGroup extends StatelessWidget {
             create: (context) => getIt<SignInBloc>(),
             child: BlocConsumer<SignInBloc, SignInState>(
               listener: (context, state) {
-                state.successOrFail.fold(
+                state.successOrFail?.fold(
-                  () => null,
+                  (result) => runAppFlowy(),
-                  (result) => result.fold(
+                  (e) => Log.error(e),
-                    (l) {},
-                    (r) async => runAppFlowy(),
-                  ),
                 );
               },
               builder: (context, state) {

frontend/appflowy_flutter/lib/plugins/database/application/calculations/calculations_listener.dart

@@ -4,11 +4,11 @@ import 'dart:typed_data';
 import 'package:appflowy/core/notification/grid_notification.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flowy_infra/notifier.dart';
 
 typedef UpdateCalculationValue
-    = Either<CalculationChangesetNotificationPB, FlowyError>;
+    = FlowyResult<CalculationChangesetNotificationPB, FlowyError>;
 
 class CalculationsListener {
   CalculationsListener({required this.viewId});
@@ -31,15 +31,15 @@ class CalculationsListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateCalculation:
         _calculationNotifier?.value = result.fold(
-          (payload) => left(
+          (payload) => FlowyResult.success(
             CalculationChangesetNotificationPB.fromBuffer(payload),
           ),
-          (err) => right(err),
+          (err) => FlowyResult.failure(err),
         );
       default:
         break;

frontend/appflowy_flutter/lib/plugins/database/application/calculations/calculations_service.dart

@@ -1,7 +1,7 @@
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class CalculationsBackendService {
   const CalculationsBackendService({required this.viewId});
@@ -9,7 +9,9 @@ class CalculationsBackendService {
   final String viewId;
 
   // Get Calculations (initial fetch)
-  Future<Either<RepeatedCalculationsPB, FlowyError>> getCalculations() async {
+
+  Future<FlowyResult<RepeatedCalculationsPB, FlowyError>>
+      getCalculations() async {
     final payload = DatabaseViewIdPB()..value = viewId;
 
     return DatabaseEventGetAllCalculations(payload).send();

frontend/appflowy_flutter/lib/plugins/database/application/cell/bloc/select_option_editor_bloc.dart

@@ -1,12 +1,10 @@
 import 'dart:async';
 
-import 'package:flutter/widgets.dart';
-
 import 'package:appflowy/plugins/database/application/cell/cell_controller_builder.dart';
 import 'package:appflowy/plugins/database/application/cell/select_option_cell_service.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/select_option_entities.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:flutter/widgets.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -52,7 +50,7 @@ class SelectOptionCellEditorBloc
             await _createOption(optionName);
             emit(
               state.copyWith(
-                filter: none(),
+                filter: null,
               ),
             );
           },
@@ -164,7 +162,7 @@ class SelectOptionCellEditorBloc
     }
 
     // clear the filter
-    emit(state.copyWith(filter: none()));
+    emit(state.copyWith(filter: null));
   }
 
   void _selectMultipleOptions(List<String> optionNames) {
@@ -186,12 +184,12 @@ class SelectOptionCellEditorBloc
 
   void _filterOption(String optionName, Emitter<SelectOptionEditorState> emit) {
     final _MakeOptionResult result = _makeOptions(
-      Some(optionName),
+      optionName,
       state.allOptions,
     );
     emit(
       state.copyWith(
-        filter: Some(optionName),
+        filter: optionName,
         options: result.options,
         createOption: result.createOption,
       ),
@@ -201,7 +199,7 @@ class SelectOptionCellEditorBloc
   Future<void> _loadOptions() async {
     final result = await _selectOptionService.getCellData();
     if (isClosed) {
-      Log.warn("Unexpected closing the bloc");
+      Log.warn("Unexpecteded closing the bloc");
       return;
     }
 
@@ -220,28 +218,26 @@ class SelectOptionCellEditorBloc
   }
 
   _MakeOptionResult _makeOptions(
-    Option<String> filter,
+    String? filter,
     List<SelectOptionPB> allOptions,
   ) {
     final List<SelectOptionPB> options = List.from(allOptions);
-    Option<String> createOption = filter;
+    String? createOption = filter;
 
-    filter.foldRight(null, (filter, previous) {
+    if (filter != null && filter.isNotEmpty) {
-      if (filter.isNotEmpty) {
       options.retainWhere((option) {
         final name = option.name.toLowerCase();
         final lFilter = filter.toLowerCase();
 
         if (name == lFilter) {
-            createOption = none();
+          createOption = null;
         }
 
         return name.contains(lFilter);
       });
     } else {
-        createOption = none();
+      createOption = null;
     }
-    });
 
     return _MakeOptionResult(
       options: options,
@@ -295,8 +291,8 @@ class SelectOptionEditorState with _$SelectOptionEditorState {
     required List<SelectOptionPB> options,
     required List<SelectOptionPB> allOptions,
     required List<SelectOptionPB> selectedOptions,
-    required Option<String> createOption,
+    required String? createOption,
-    required Option<String> filter,
+    required String? filter,
   }) = _SelectOptionEditorState;
 
   factory SelectOptionEditorState.initial(SelectOptionCellController context) {
@@ -305,8 +301,8 @@ class SelectOptionEditorState with _$SelectOptionEditorState {
       options: data?.options ?? [],
       allOptions: data?.options ?? [],
       selectedOptions: data?.selectOptions ?? [],
-      createOption: none(),
+      createOption: null,
-      filter: none(),
+      filter: null,
     );
   }
 }
@@ -318,5 +314,5 @@ class _MakeOptionResult {
   });
 
   List<SelectOptionPB> options;
-  Option<String> createOption;
+  String? createOption;
 }

frontend/appflowy_flutter/lib/plugins/database/application/cell/cell_controller.dart

@@ -10,7 +10,6 @@ import 'package:appflowy/plugins/database/application/row/row_service.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:flutter/foundation.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -173,7 +172,7 @@ class CellController<T, D> {
   Future<void> saveCellData(
     D data, {
     bool debounce = false,
-    void Function(Option<FlowyError>)? onFinish,
+    void Function(FlowyError?)? onFinish,
   }) async {
     _loadDataOperation?.cancel();
     if (debounce) {

frontend/appflowy_flutter/lib/plugins/database/application/cell/cell_data_persistence.dart

@@ -1,5 +1,4 @@
 import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
-import 'package:dartz/dartz.dart';
 
 import 'cell_controller.dart';
 import 'cell_service.dart';
@@ -7,7 +6,7 @@ import 'cell_service.dart';
 /// Save the cell data to disk
 /// You can extend this class to do custom operations.
 abstract class CellDataPersistence<D> {
-  Future<Option<FlowyError>> save({
+  Future<FlowyError?> save({
     required String viewId,
     required CellContext cellContext,
     required D data,
@@ -18,7 +17,7 @@ class TextCellDataPersistence implements CellDataPersistence<String> {
   TextCellDataPersistence();
 
   @override
-  Future<Option<FlowyError>> save({
+  Future<FlowyError?> save({
     required String viewId,
     required CellContext cellContext,
     required String data,
@@ -30,8 +29,8 @@ class TextCellDataPersistence implements CellDataPersistence<String> {
     );
     return fut.then((result) {
       return result.fold(
-        (l) => none(),
+        (l) => null,
-        (err) => Some(err),
+        (err) => err,
       );
     });
   }

frontend/appflowy_flutter/lib/plugins/database/application/cell/cell_listener.dart

@@ -4,12 +4,12 @@ import 'dart:typed_data';
 import 'package:appflowy/core/notification/grid_notification.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flowy_infra/notifier.dart';
 
 import '../row/row_service.dart';
 
-typedef UpdateFieldNotifiedValue = Either<Unit, FlowyError>;
+typedef UpdateFieldNotifiedValue = FlowyResult<void, FlowyError>;
 
 class CellListener {
   CellListener({required this.rowId, required this.fieldId});
@@ -29,12 +29,15 @@ class CellListener {
     );
   }
 
-  void _handler(DatabaseNotification ty, Either<Uint8List, FlowyError> result) {
+  void _handler(
+    DatabaseNotification ty,
+    FlowyResult<Uint8List, FlowyError> result,
+  ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateCell:
         result.fold(
-          (payload) => _updateCellNotifier?.value = left(unit),
+          (payload) => _updateCellNotifier?.value = FlowyResult.success(null),
-          (error) => _updateCellNotifier?.value = right(error),
+          (error) => _updateCellNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/cell/cell_service.dart

@@ -1,16 +1,16 @@
 import 'dart:async';
 
-import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 import 'cell_controller.dart';
 
 class CellBackendService {
   CellBackendService();
 
-  static Future<Either<void, FlowyError>> updateCell({
+  static Future<FlowyResult<void, FlowyError>> updateCell({
     required String viewId,
     required CellContext cellContext,
     required String data,
@@ -23,7 +23,7 @@ class CellBackendService {
     return DatabaseEventUpdateCell(payload).send();
   }
 
-  static Future<Either<CellPB, FlowyError>> getCell({
+  static Future<FlowyResult<CellPB, FlowyError>> getCell({
     required String viewId,
     required CellContext cellContext,
   }) {

frontend/appflowy_flutter/lib/plugins/database/application/cell/checklist_cell_service.dart

@@ -2,7 +2,7 @@ import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/checklist_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/select_option_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:protobuf/protobuf.dart';
 
 class ChecklistCellBackendService {
@@ -16,7 +16,7 @@ class ChecklistCellBackendService {
   final String fieldId;
   final String rowId;
 
-  Future<Either<Unit, FlowyError>> create({
+  Future<FlowyResult<void, FlowyError>> create({
     required String name,
   }) {
     final payload = ChecklistCellDataChangesetPB.create()
@@ -28,7 +28,7 @@ class ChecklistCellBackendService {
     return DatabaseEventUpdateChecklistCell(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> delete({
+  Future<FlowyResult<void, FlowyError>> delete({
     required List<String> optionIds,
   }) {
     final payload = ChecklistCellDataChangesetPB.create()
@@ -40,7 +40,7 @@ class ChecklistCellBackendService {
     return DatabaseEventUpdateChecklistCell(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> select({
+  Future<FlowyResult<void, FlowyError>> select({
     required String optionId,
   }) {
     final payload = ChecklistCellDataChangesetPB.create()
@@ -52,7 +52,7 @@ class ChecklistCellBackendService {
     return DatabaseEventUpdateChecklistCell(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> updateName({
+  Future<FlowyResult<void, FlowyError>> updateName({
     required SelectOptionPB option,
     required name,
   }) {

frontend/appflowy_flutter/lib/plugins/database/application/cell/date_cell_service.dart

@@ -2,7 +2,7 @@ import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/cell_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/date_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:fixnum/fixnum.dart';
 
 final class DateCellBackendService {
@@ -17,7 +17,7 @@ final class DateCellBackendService {
 
   final CellIdPB cellId;
 
-  Future<Either<Unit, FlowyError>> update({
+  Future<FlowyResult<void, FlowyError>> update({
     required bool includeTime,
     required bool isRange,
     DateTime? date,
@@ -52,7 +52,7 @@ final class DateCellBackendService {
     return DatabaseEventUpdateDateCell(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> clear() {
+  Future<FlowyResult<void, FlowyError>> clear() {
     final payload = DateCellChangesetPB.create()
       ..cellId = cellId
       ..clearFlag = true;

frontend/appflowy_flutter/lib/plugins/database/application/cell/select_option_cell_service.dart

@@ -1,9 +1,9 @@
 import 'package:appflowy/plugins/database/application/field/type_option/type_option_service.dart';
-import 'package:appflowy_backend/protobuf/flowy-database2/select_option_entities.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/cell_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/select_option_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class SelectOptionCellBackendService {
   SelectOptionCellBackendService({
@@ -16,7 +16,7 @@ class SelectOptionCellBackendService {
   final String fieldId;
   final String rowId;
 
-  Future<Either<Unit, FlowyError>> create({
+  Future<FlowyResult<void, FlowyError>> create({
     required String name,
     bool isSelected = true,
   }) {
@@ -34,13 +34,13 @@ class SelectOptionCellBackendService {
 
             return DatabaseEventInsertOrUpdateSelectOption(payload).send();
           },
-          (r) => right(r),
+          (r) => FlowyResult.failure(r),
         );
       },
     );
   }
 
-  Future<Either<Unit, FlowyError>> update({
+  Future<FlowyResult<void, FlowyError>> update({
     required SelectOptionPB option,
   }) {
     final payload = RepeatedSelectOptionPayload()
@@ -52,7 +52,7 @@ class SelectOptionCellBackendService {
     return DatabaseEventInsertOrUpdateSelectOption(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> delete({
+  Future<FlowyResult<void, FlowyError>> delete({
     required Iterable<SelectOptionPB> options,
   }) {
     final payload = RepeatedSelectOptionPayload()
@@ -64,7 +64,7 @@ class SelectOptionCellBackendService {
     return DatabaseEventDeleteSelectOption(payload).send();
   }
 
-  Future<Either<SelectOptionCellDataPB, FlowyError>> getCellData() {
+  Future<FlowyResult<SelectOptionCellDataPB, FlowyError>> getCellData() {
     final payload = CellIdPB()
       ..viewId = viewId
       ..fieldId = fieldId
@@ -73,7 +73,7 @@ class SelectOptionCellBackendService {
     return DatabaseEventGetSelectOptionCellData(payload).send();
   }
 
-  Future<Either<void, FlowyError>> select({
+  Future<FlowyResult<void, FlowyError>> select({
     required Iterable<String> optionIds,
   }) {
     final payload = SelectOptionCellChangesetPB()
@@ -83,7 +83,7 @@ class SelectOptionCellBackendService {
     return DatabaseEventUpdateSelectOptionCell(payload).send();
   }
 
-  Future<Either<void, FlowyError>> unSelect({
+  Future<FlowyResult<void, FlowyError>> unSelect({
     required Iterable<String> optionIds,
   }) {
     final payload = SelectOptionCellChangesetPB()

frontend/appflowy_flutter/lib/plugins/database/application/database_controller.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:appflowy/plugins/database/application/field/field_controller.dart';
 import 'package:appflowy/plugins/database/application/view/view_cache.dart';
 import 'package:appflowy_backend/log.dart';
@@ -10,17 +12,16 @@ import 'package:appflowy_backend/protobuf/flowy-database2/row_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/setting_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:collection/collection.dart';
-import 'dart:async';
-import 'package:dartz/dartz.dart';
 import 'package:flutter/material.dart';
 
 import 'database_view_service.dart';
 import 'defines.dart';
+import 'group/group_listener.dart';
 import 'layout/layout_service.dart';
 import 'layout/layout_setting_listener.dart';
 import 'row/row_cache.dart';
-import 'group/group_listener.dart';
 
 typedef OnGroupConfigurationChanged = void Function(List<GroupSettingPB>);
 typedef OnGroupByField = void Function(List<GroupPB>);
@@ -136,7 +137,7 @@ class DatabaseController {
     }
   }
 
-  Future<Either<Unit, FlowyError>> open() async {
+  Future<FlowyResult<void, FlowyError>> open() async {
     return _databaseViewBackendSvc.openDatabase().then((result) {
       return result.fold(
         (DatabasePB database) async {
@@ -157,21 +158,21 @@ class DatabaseController {
               return Future(() async {
                 await _loadGroups();
                 await _loadLayoutSetting();
-                return left(fields);
+                return FlowyResult.success(fields);
               });
             },
             (err) {
               Log.error(err);
-              return right(err);
+              return FlowyResult.failure(err);
             },
           );
         },
-        (err) => right(err),
+        (err) => FlowyResult.failure(err),
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> moveGroupRow({
+  Future<FlowyResult<void, FlowyError>> moveGroupRow({
     required RowMetaPB fromRow,
     required String fromGroupId,
     required String toGroupId,
@@ -185,7 +186,7 @@ class DatabaseController {
     );
   }
 
-  Future<Either<Unit, FlowyError>> moveRow({
+  Future<FlowyResult<void, FlowyError>> moveRow({
     required String fromRowId,
     required String toRowId,
   }) {
@@ -195,7 +196,7 @@ class DatabaseController {
     );
   }
 
-  Future<Either<Unit, FlowyError>> moveGroup({
+  Future<FlowyResult<void, FlowyError>> moveGroup({
     required String fromGroupId,
     required String toGroupId,
   }) {

frontend/appflowy_flutter/lib/plugins/database/application/database_service.dart

@@ -1,13 +1,16 @@
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class DatabaseBackendService {
-  static Future<Either<List<DatabaseDescriptionPB>, FlowyError>>
+  static Future<FlowyResult<List<DatabaseDescriptionPB>, FlowyError>>
       getAllDatabases() {
     return DatabaseEventGetDatabases().send().then((result) {
-      return result.fold((l) => left(l.items), (r) => right(r));
+      return result.fold(
+        (l) => FlowyResult.success(l.items),
+        (r) => FlowyResult.failure(r),
+      );
     });
   }
 }

frontend/appflowy_flutter/lib/plugins/database/application/database_view_service.dart

@@ -3,7 +3,7 @@ import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 import 'layout/layout_service.dart';
 
@@ -12,15 +12,15 @@ class DatabaseViewBackendService {
 
   final String viewId;
 
-  /// Returns the datbaase id associated with the view.
+  /// Returns the database id associated with the view.
-  Future<Either<String, FlowyError>> getDatabaseId() async {
+  Future<FlowyResult<String, FlowyError>> getDatabaseId() async {
     final payload = DatabaseViewIdPB(value: viewId);
     return DatabaseEventGetDatabaseId(payload)
         .send()
-        .then((value) => value.leftMap((l) => l.value));
+        .then((value) => value.map((l) => l.value));
   }
 
-  static Future<Either<ViewPB, FlowyError>> updateLayout({
+  static Future<FlowyResult<ViewPB, FlowyError>> updateLayout({
     required String viewId,
     required DatabaseLayoutPB layout,
   }) {
@@ -31,12 +31,12 @@ class DatabaseViewBackendService {
     return FolderEventUpdateView(payload).send();
   }
 
-  Future<Either<DatabasePB, FlowyError>> openDatabase() async {
+  Future<FlowyResult<DatabasePB, FlowyError>> openDatabase() async {
     final payload = DatabaseViewIdPB(value: viewId);
     return DatabaseEventGetDatabase(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> moveGroupRow({
+  Future<FlowyResult<void, FlowyError>> moveGroupRow({
     required RowId fromRowId,
     required String fromGroupId,
     required String toGroupId,
@@ -55,7 +55,7 @@ class DatabaseViewBackendService {
     return DatabaseEventMoveGroupRow(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> moveRow({
+  Future<FlowyResult<void, FlowyError>> moveRow({
     required String fromRowId,
     required String toRowId,
   }) {
@@ -67,7 +67,7 @@ class DatabaseViewBackendService {
     return DatabaseEventMoveRow(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> moveGroup({
+  Future<FlowyResult<void, FlowyError>> moveGroup({
     required String fromGroupId,
     required String toGroupId,
   }) {
@@ -79,7 +79,7 @@ class DatabaseViewBackendService {
     return DatabaseEventMoveGroup(payload).send();
   }
 
-  Future<Either<List<FieldPB>, FlowyError>> getFields({
+  Future<FlowyResult<List<FieldPB>, FlowyError>> getFields({
     List<FieldIdPB>? fieldIds,
   }) {
     final payload = GetFieldPayloadPB.create()..viewId = viewId;
@@ -88,11 +88,14 @@ class DatabaseViewBackendService {
       payload.fieldIds = RepeatedFieldIdPB(items: fieldIds);
     }
     return DatabaseEventGetFields(payload).send().then((result) {
-      return result.fold((l) => left(l.items), (r) => right(r));
+      return result.fold(
+        (l) => FlowyResult.success(l.items),
+        (r) => FlowyResult.failure(r),
+      );
     });
   }
 
-  Future<Either<DatabaseLayoutSettingPB, FlowyError>> getLayoutSetting(
+  Future<FlowyResult<DatabaseLayoutSettingPB, FlowyError>> getLayoutSetting(
     DatabaseLayoutPB layoutType,
   ) {
     final payload = DatabaseLayoutMetaPB.create()
@@ -101,7 +104,7 @@ class DatabaseViewBackendService {
     return DatabaseEventGetLayoutSetting(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> updateLayoutSetting({
+  Future<FlowyResult<void, FlowyError>> updateLayoutSetting({
     required DatabaseLayoutPB layoutType,
     BoardLayoutSettingPB? boardLayoutSetting,
     CalendarLayoutSettingPB? calendarLayoutSetting,
@@ -121,12 +124,12 @@ class DatabaseViewBackendService {
     return DatabaseEventSetLayoutSetting(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> closeView() {
+  Future<FlowyResult<void, FlowyError>> closeView() {
     final request = ViewIdPB(value: viewId);
     return FolderEventCloseView(request).send();
   }
 
-  Future<Either<RepeatedGroupPB, FlowyError>> loadGroups() {
+  Future<FlowyResult<RepeatedGroupPB, FlowyError>> loadGroups() {
     final payload = DatabaseViewIdPB(value: viewId);
     return DatabaseEventGetGroups(payload).send();
   }

frontend/appflowy_flutter/lib/plugins/database/application/defines.dart

@@ -5,7 +5,7 @@ import 'package:appflowy/plugins/database/grid/presentation/widgets/filter/filte
 import 'package:appflowy/plugins/database/grid/presentation/widgets/sort/sort_info.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
 import 'field/field_info.dart';
@@ -38,7 +38,7 @@ class LoadingState with _$LoadingState {
   const factory LoadingState.idle() = _Idle;
   const factory LoadingState.loading() = _Loading;
   const factory LoadingState.finish(
-    Either<Unit, FlowyError> successOrFail,
+    FlowyResult<void, FlowyError> successOrFail,
   ) = _Finish;
 
   const LoadingState._();

frontend/appflowy_flutter/lib/plugins/database/application/field/field_controller.dart

@@ -20,8 +20,8 @@ import 'package:appflowy_backend/protobuf/flowy-database2/setting_entities.pb.da
 import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/util.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:collection/collection.dart';
-import 'package:dartz/dartz.dart';
 import 'package:flutter/foundation.dart';
 
 import '../setting/setting_service.dart';
@@ -382,7 +382,7 @@ class FieldController {
     );
   }
 
-  /// Listen for databse setting changes in the backend.
+  /// Listen for database setting changes in the backend.
   void _listenOnSettingChanges() {
     _settingListener.start(
       onSettingUpdated: (result) {
@@ -581,7 +581,7 @@ class FieldController {
   }
 
   /// Load all of the fields. This is required when opening the database
-  Future<Either<Unit, FlowyError>> loadFields({
+  Future<FlowyResult<void, FlowyError>> loadFields({
     required List<FieldIdPB> fieldIds,
   }) async {
     final result = await _databaseViewBackendSvc.getFields(fieldIds: fieldIds);
@@ -589,7 +589,7 @@ class FieldController {
       () => result.fold(
         (newFields) async {
           if (_isDisposed) {
-            return left(unit);
+            return FlowyResult.success(null);
           }
 
           _fieldNotifier.fieldInfos =
@@ -602,54 +602,54 @@ class FieldController {
           ]);
           _updateFieldInfos();
 
-          return left(unit);
+          return FlowyResult.success(null);
         },
-        (err) => right(err),
+        (err) => FlowyResult.failure(err),
       ),
     );
   }
 
   /// Load all the filters from the backend. Required by `loadFields`
-  Future<Either<Unit, FlowyError>> _loadFilters() async {
+  Future<FlowyResult<void, FlowyError>> _loadFilters() async {
     return _filterBackendSvc.getAllFilters().then((result) {
       return result.fold(
         (filterPBs) {
           _filterNotifier?.filters = _filterInfoListFromPBs(filterPBs);
-          return left(unit);
+          return FlowyResult.success(null);
         },
-        (err) => right(err),
+        (err) => FlowyResult.failure(err),
       );
     });
   }
 
   /// Load all the sorts from the backend. Required by `loadFields`
-  Future<Either<Unit, FlowyError>> _loadSorts() async {
+  Future<FlowyResult<void, FlowyError>> _loadSorts() async {
     return _sortBackendSvc.getAllSorts().then((result) {
       return result.fold(
         (sortPBs) {
           _sortNotifier?.sorts = _sortInfoListFromPBs(sortPBs);
-          return left(unit);
+          return FlowyResult.success(null);
         },
-        (err) => right(err),
+        (err) => FlowyResult.failure(err),
       );
     });
   }
 
   /// Load all the field settings from the backend. Required by `loadFields`
-  Future<Either<Unit, FlowyError>> _loadAllFieldSettings() async {
+  Future<FlowyResult<void, FlowyError>> _loadAllFieldSettings() async {
     return _fieldSettingsBackendSvc.getAllFieldSettings().then((result) {
       return result.fold(
         (fieldSettingsList) {
           _fieldSettings.clear();
           _fieldSettings.addAll(fieldSettingsList);
-          return left(unit);
+          return FlowyResult.success(null);
         },
-        (err) => right(err),
+        (err) => FlowyResult.failure(err),
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> _loadSettings() async {
+  Future<FlowyResult<void, FlowyError>> _loadSettings() async {
     return SettingBackendService(viewId: viewId).getSetting().then(
           (result) => result.fold(
             (setting) {
@@ -658,9 +658,9 @@ class FieldController {
                 _groupConfigurationByFieldId[configuration.fieldId] =
                     configuration;
               }
-              return left(unit);
+              return FlowyResult.success(null);
             },
-            (err) => right(err),
+            (err) => FlowyResult.failure(err),
           ),
         );
   }

frontend/appflowy_flutter/lib/plugins/database/application/field/field_editor_bloc.dart

@@ -4,7 +4,7 @@ import 'package:appflowy/plugins/database/application/field_settings/field_setti
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -111,7 +111,7 @@ class FieldEditorBloc extends Bloc<FieldEditorEvent, FieldEditorState> {
     );
   }
 
-  void _logIfError(Either<Unit, FlowyError> result) {
+  void _logIfError(FlowyResult<void, FlowyError> result) {
     result.fold(
       (l) => null,
       (err) => Log.error(err),

frontend/appflowy_flutter/lib/plugins/database/application/field/field_listener.dart

@@ -5,7 +5,7 @@ import 'package:appflowy/core/notification/grid_notification.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flowy_infra/notifier.dart';
 
 typedef UpdateFieldNotifiedValue = FieldPB;
@@ -30,7 +30,7 @@ class SingleFieldListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateField:
@@ -51,7 +51,7 @@ class SingleFieldListener {
 }
 
 typedef UpdateFieldsNotifiedValue
-    = Either<DatabaseFieldChangesetPB, FlowyError>;
+    = FlowyResult<DatabaseFieldChangesetPB, FlowyError>;
 
 class FieldsListener {
   FieldsListener({required this.viewId});
@@ -72,13 +72,16 @@ class FieldsListener {
     );
   }
 
-  void _handler(DatabaseNotification ty, Either<Uint8List, FlowyError> result) {
+  void _handler(
+    DatabaseNotification ty,
+    FlowyResult<Uint8List, FlowyError> result,
+  ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateFields:
         result.fold(
           (payload) => updateFieldsNotifier?.value =
-              left(DatabaseFieldChangesetPB.fromBuffer(payload)),
+              FlowyResult.success(DatabaseFieldChangesetPB.fromBuffer(payload)),
-          (error) => updateFieldsNotifier?.value = right(error),
+          (error) => updateFieldsNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/field/field_service.dart

@@ -3,7 +3,7 @@ import 'dart:typed_data';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 /// FieldService provides many field-related interfaces event functions. Check out
 /// `rust-lib/flowy-database/event_map.rs` for a list of events and their
@@ -16,7 +16,7 @@ class FieldBackendService {
 
   /// Create a field in a database view. The position will only be applicable
   /// in this view; for other views it will be appended to the end
-  static Future<Either<FieldPB, FlowyError>> createField({
+  static Future<FlowyResult<FieldPB, FlowyError>> createField({
     required String viewId,
     FieldType fieldType = FieldType.RichText,
     String? fieldName,
@@ -35,7 +35,7 @@ class FieldBackendService {
   }
 
   /// Reorder a field within a database view
-  static Future<Either<Unit, FlowyError>> moveField({
+  static Future<FlowyResult<void, FlowyError>> moveField({
     required String viewId,
     required String fromFieldId,
     required String toFieldId,
@@ -50,7 +50,7 @@ class FieldBackendService {
   }
 
   /// Delete a field
-  static Future<Either<Unit, FlowyError>> deleteField({
+  static Future<FlowyResult<void, FlowyError>> deleteField({
     required String viewId,
     required String fieldId,
   }) {
@@ -63,7 +63,7 @@ class FieldBackendService {
   }
 
   /// Duplicate a field
-  static Future<Either<Unit, FlowyError>> duplicateField({
+  static Future<FlowyResult<void, FlowyError>> duplicateField({
     required String viewId,
     required String fieldId,
   }) {
@@ -76,7 +76,7 @@ class FieldBackendService {
   }
 
   /// Update a field's properties
-  Future<Either<Unit, FlowyError>> updateField({
+  Future<FlowyResult<void, FlowyError>> updateField({
     String? name,
     bool? frozen,
   }) {
@@ -96,7 +96,7 @@ class FieldBackendService {
   }
 
   /// Change a field's type
-  static Future<Either<Unit, FlowyError>> updateFieldType({
+  static Future<FlowyResult<void, FlowyError>> updateFieldType({
     required String viewId,
     required String fieldId,
     required FieldType fieldType,
@@ -110,7 +110,7 @@ class FieldBackendService {
   }
 
   /// Update a field's type option data
-  static Future<Either<Unit, FlowyError>> updateFieldTypeOption({
+  static Future<FlowyResult<void, FlowyError>> updateFieldTypeOption({
     required String viewId,
     required String fieldId,
     required List<int> typeOptionData,
@@ -124,14 +124,14 @@ class FieldBackendService {
   }
 
   /// Returns the primary field of the view.
-  static Future<Either<FieldPB, FlowyError>> getPrimaryField({
+  static Future<FlowyResult<FieldPB, FlowyError>> getPrimaryField({
     required String viewId,
   }) {
     final payload = DatabaseViewIdPB.create()..value = viewId;
     return DatabaseEventGetPrimaryField(payload).send();
   }
 
-  Future<Either<FieldPB, FlowyError>> createBefore({
+  Future<FlowyResult<FieldPB, FlowyError>> createBefore({
     FieldType fieldType = FieldType.RichText,
     String? fieldName,
     Uint8List? typeOptionData,
@@ -148,7 +148,7 @@ class FieldBackendService {
     );
   }
 
-  Future<Either<FieldPB, FlowyError>> createAfter({
+  Future<FlowyResult<FieldPB, FlowyError>> createAfter({
     FieldType fieldType = FieldType.RichText,
     String? fieldName,
     Uint8List? typeOptionData,
@@ -165,7 +165,7 @@ class FieldBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> updateType({
+  Future<FlowyResult<void, FlowyError>> updateType({
     required FieldType fieldType,
   }) =>
       updateFieldType(
@@ -174,9 +174,9 @@ class FieldBackendService {
         fieldType: fieldType,
       );
 
-  Future<Either<Unit, FlowyError>> delete() =>
+  Future<FlowyResult<void, FlowyError>> delete() =>
       deleteField(viewId: viewId, fieldId: fieldId);
 
-  Future<Either<Unit, FlowyError>> duplicate() =>
+  Future<FlowyResult<void, FlowyError>> duplicate() =>
       duplicateField(viewId: viewId, fieldId: fieldId);
 }

frontend/appflowy_flutter/lib/plugins/database/application/field/type_option/select_option_type_option_bloc.dart

@@ -1,5 +1,4 @@
 import 'package:appflowy_backend/protobuf/flowy-database2/select_option_entities.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -28,10 +27,10 @@ class SelectOptionTypeOptionBloc
             emit(state.copyWith(options: options));
           },
           addingOption: () {
-            emit(state.copyWith(isEditingOption: true, newOptionName: none()));
+            emit(state.copyWith(isEditingOption: true, newOptionName: null));
           },
           endAddingOption: () {
-            emit(state.copyWith(isEditingOption: false, newOptionName: none()));
+            emit(state.copyWith(isEditingOption: false, newOptionName: null));
           },
           updateOption: (option) {
             final List<SelectOptionPB> options =
@@ -69,13 +68,13 @@ class SelectOptionTypeOptionState with _$SelectOptionTypeOptionState {
   const factory SelectOptionTypeOptionState({
     required List<SelectOptionPB> options,
     required bool isEditingOption,
-    required Option<String> newOptionName,
+    required String? newOptionName,
   }) = _SelectOptionTypeOptionState;
 
   factory SelectOptionTypeOptionState.initial(List<SelectOptionPB> options) =>
       SelectOptionTypeOptionState(
         options: options,
         isEditingOption: false,
-        newOptionName: none(),
+        newOptionName: null,
       );
 }

frontend/appflowy_flutter/lib/plugins/database/application/field/type_option/type_option_service.dart

@@ -1,7 +1,7 @@
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class TypeOptionBackendService {
   TypeOptionBackendService({
@@ -12,7 +12,7 @@ class TypeOptionBackendService {
   final String viewId;
   final String fieldId;
 
-  Future<Either<SelectOptionPB, FlowyError>> newOption({
+  Future<FlowyResult<SelectOptionPB, FlowyError>> newOption({
     required String name,
   }) {
     final payload = CreateSelectOptionPayloadPB.create()

frontend/appflowy_flutter/lib/plugins/database/application/field_settings/field_settings_listener.dart

@@ -3,10 +3,10 @@ import 'dart:typed_data';
 import 'package:appflowy/core/notification/grid_notification.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flowy_infra/notifier.dart';
 
-typedef FieldSettingsValue = Either<FieldSettingsPB, FlowyError>;
+typedef FieldSettingsValue = FlowyResult<FieldSettingsPB, FlowyError>;
 
 class FieldSettingsListener {
   FieldSettingsListener({required this.viewId});
@@ -29,14 +29,14 @@ class FieldSettingsListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateFieldSettings:
         result.fold(
           (payload) => _fieldSettingsNotifier?.value =
-              left(FieldSettingsPB.fromBuffer(payload)),
+              FlowyResult.success(FieldSettingsPB.fromBuffer(payload)),
-          (error) => _fieldSettingsNotifier?.value = right(error),
+          (error) => _fieldSettingsNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/field_settings/field_settings_service.dart

@@ -1,14 +1,14 @@
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class FieldSettingsBackendService {
   FieldSettingsBackendService({required this.viewId});
 
   final String viewId;
 
-  Future<Either<FieldSettingsPB, FlowyError>> getFieldSettings(
+  Future<FlowyResult<FieldSettingsPB, FlowyError>> getFieldSettings(
     String fieldId,
   ) {
     final id = FieldIdPB(fieldId: fieldId);
@@ -25,14 +25,14 @@ class FieldSettingsBackendService {
             fieldSetting.visibility = FieldVisibility.AlwaysShown;
           }
 
-          return left(fieldSetting);
+          return FlowyResult.success(fieldSetting);
         },
-        (r) => right(r),
+        (r) => FlowyResult.failure(r),
       );
     });
   }
 
-  Future<Either<List<FieldSettingsPB>, FlowyError>> getAllFieldSettings() {
+  Future<FlowyResult<List<FieldSettingsPB>, FlowyError>> getAllFieldSettings() {
     final payload = DatabaseViewIdPB()..value = viewId;
 
     return DatabaseEventGetAllFieldSettings(payload).send().then((result) {
@@ -47,14 +47,14 @@ class FieldSettingsBackendService {
             fieldSettings.add(fieldSetting);
           }
 
-          return left(fieldSettings);
+          return FlowyResult.success(fieldSettings);
         },
-        (r) => right(r),
+        (r) => FlowyResult.failure(r),
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> updateFieldSettings({
+  Future<FlowyResult<void, FlowyError>> updateFieldSettings({
     required String fieldId,
     FieldVisibility? fieldVisibility,
     double? width,

frontend/appflowy_flutter/lib/plugins/database/application/filter/filter_listener.dart

@@ -1,15 +1,15 @@
 import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
-import 'package:flowy_infra/notifier.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/filter_changeset.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/util.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flowy_infra/notifier.dart';
 
 typedef UpdateFilterNotifiedValue
-    = Either<FilterChangesetNotificationPB, FlowyError>;
+    = FlowyResult<FilterChangesetNotificationPB, FlowyError>;
 
 class FiltersListener {
   FiltersListener({required this.viewId});
@@ -32,14 +32,15 @@ class FiltersListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateFilter:
         result.fold(
-          (payload) => _filterNotifier?.value =
+          (payload) => _filterNotifier?.value = FlowyResult.success(
-              left(FilterChangesetNotificationPB.fromBuffer(payload)),
+            FilterChangesetNotificationPB.fromBuffer(payload),
-          (error) => _filterNotifier?.value = right(error),
+          ),
+          (error) => _filterNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:
@@ -103,7 +104,7 @@ class FilterListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateFilter:

frontend/appflowy_flutter/lib/plugins/database/application/filter/filter_service.dart

@@ -1,10 +1,8 @@
-import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/log.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/checkbox_filter.pbserver.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/checklist_filter.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/date_filter.pbserver.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/field_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/number_filter.pb.dart';
@@ -12,6 +10,8 @@ import 'package:appflowy_backend/protobuf/flowy-database2/select_option_filter.p
 import 'package:appflowy_backend/protobuf/flowy-database2/setting_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/text_filter.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/util.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:fixnum/fixnum.dart' as $fixnum;
 
 class FilterBackendService {
@@ -19,18 +19,18 @@ class FilterBackendService {
 
   final String viewId;
 
-  Future<Either<List<FilterPB>, FlowyError>> getAllFilters() {
+  Future<FlowyResult<List<FilterPB>, FlowyError>> getAllFilters() {
     final payload = DatabaseViewIdPB()..value = viewId;
 
     return DatabaseEventGetAllFilters(payload).send().then((result) {
       return result.fold(
-        (repeated) => left(repeated.items),
+        (repeated) => FlowyResult.success(repeated.items),
-        (r) => right(r),
+        (r) => FlowyResult.failure(r),
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> insertTextFilter({
+  Future<FlowyResult<void, FlowyError>> insertTextFilter({
     required String fieldId,
     String? filterId,
     required TextFilterConditionPB condition,
@@ -48,7 +48,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertCheckboxFilter({
+  Future<FlowyResult<void, FlowyError>> insertCheckboxFilter({
     required String fieldId,
     String? filterId,
     required CheckboxFilterConditionPB condition,
@@ -63,7 +63,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertNumberFilter({
+  Future<FlowyResult<void, FlowyError>> insertNumberFilter({
     required String fieldId,
     String? filterId,
     required NumberFilterConditionPB condition,
@@ -81,7 +81,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertDateFilter({
+  Future<FlowyResult<void, FlowyError>> insertDateFilter({
     required String fieldId,
     String? filterId,
     required DateFilterConditionPB condition,
@@ -120,7 +120,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertURLFilter({
+  Future<FlowyResult<void, FlowyError>> insertURLFilter({
     required String fieldId,
     String? filterId,
     required TextFilterConditionPB condition,
@@ -138,7 +138,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertSelectOptionFilter({
+  Future<FlowyResult<void, FlowyError>> insertSelectOptionFilter({
     required String fieldId,
     required FieldType fieldType,
     required SelectOptionConditionPB condition,
@@ -157,7 +157,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertChecklistFilter({
+  Future<FlowyResult<void, FlowyError>> insertChecklistFilter({
     required String fieldId,
     required ChecklistFilterConditionPB condition,
     String? filterId,
@@ -173,7 +173,7 @@ class FilterBackendService {
     );
   }
 
-  Future<Either<Unit, FlowyError>> insertFilter({
+  Future<FlowyResult<void, FlowyError>> insertFilter({
     required String fieldId,
     String? filterId,
     required FieldType fieldType,
@@ -194,16 +194,16 @@ class FilterBackendService {
       ..updateFilter = insertFilterPayload;
     return DatabaseEventUpdateDatabaseSetting(payload).send().then((result) {
       return result.fold(
-        (l) => left(l),
+        (l) => FlowyResult.success(l),
         (err) {
           Log.error(err);
-          return right(err);
+          return FlowyResult.failure(err);
         },
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> deleteFilter({
+  Future<FlowyResult<void, FlowyError>> deleteFilter({
     required String fieldId,
     required String filterId,
     required FieldType fieldType,
@@ -220,10 +220,10 @@ class FilterBackendService {
 
     return DatabaseEventUpdateDatabaseSetting(payload).send().then((result) {
       return result.fold(
-        (l) => left(l),
+        (l) => FlowyResult.success(l),
         (err) {
           Log.error(err);
-          return right(err);
+          return FlowyResult.failure(err);
         },
       );
     });

frontend/appflowy_flutter/lib/plugins/database/application/group/group_listener.dart

@@ -1,17 +1,17 @@
 import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
-import 'package:flowy_infra/notifier.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/group.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/group_changeset.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flowy_infra/notifier.dart';
 
 typedef GroupConfigurationUpdateValue
-    = Either<List<GroupSettingPB>, FlowyError>;
+    = FlowyResult<List<GroupSettingPB>, FlowyError>;
-typedef GroupUpdateValue = Either<GroupChangesPB, FlowyError>;
+typedef GroupUpdateValue = FlowyResult<GroupChangesPB, FlowyError>;
-typedef GroupByNewFieldValue = Either<List<GroupPB>, FlowyError>;
+typedef GroupByNewFieldValue = FlowyResult<List<GroupPB>, FlowyError>;
 
 class DatabaseGroupListener {
   DatabaseGroupListener(this.viewId);
@@ -37,21 +37,22 @@ class DatabaseGroupListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateNumOfGroups:
         result.fold(
           (payload) => _numOfGroupsNotifier?.value =
-              left(GroupChangesPB.fromBuffer(payload)),
+              FlowyResult.success(GroupChangesPB.fromBuffer(payload)),
-          (error) => _numOfGroupsNotifier?.value = right(error),
+          (error) => _numOfGroupsNotifier?.value = FlowyResult.failure(error),
         );
         break;
       case DatabaseNotification.DidGroupByField:
         result.fold(
-          (payload) => _groupByFieldNotifier?.value =
+          (payload) => _groupByFieldNotifier?.value = FlowyResult.success(
-              left(GroupChangesPB.fromBuffer(payload).initialGroups),
+            GroupChangesPB.fromBuffer(payload).initialGroups,
-          (error) => _groupByFieldNotifier?.value = right(error),
+          ),
+          (error) => _groupByFieldNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/group/group_service.dart

@@ -1,14 +1,14 @@
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/group.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class GroupBackendService {
   GroupBackendService(this.viewId);
 
   final String viewId;
 
-  Future<Either<Unit, FlowyError>> groupByField({
+  Future<FlowyResult<void, FlowyError>> groupByField({
     required String fieldId,
   }) {
     final payload = GroupByFieldPayloadPB.create()
@@ -18,7 +18,7 @@ class GroupBackendService {
     return DatabaseEventSetGroupByField(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> updateGroup({
+  Future<FlowyResult<void, FlowyError>> updateGroup({
     required String groupId,
     required String fieldId,
     String? name,
@@ -38,7 +38,7 @@ class GroupBackendService {
     return DatabaseEventUpdateGroup(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> createGroup({
+  Future<FlowyResult<void, FlowyError>> createGroup({
     required String name,
     String groupConfigId = "",
   }) {
@@ -49,7 +49,7 @@ class GroupBackendService {
     return DatabaseEventCreateGroup(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> deleteGroup({
+  Future<FlowyResult<void, FlowyError>> deleteGroup({
     required String groupId,
   }) {
     final payload = DeleteGroupPayloadPB.create()

frontend/appflowy_flutter/lib/plugins/database/application/layout/layout_setting_listener.dart

@@ -1,12 +1,12 @@
 import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
-import 'package:flowy_infra/notifier.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flowy_infra/notifier.dart';
 
-typedef LayoutSettingsValue<T> = Either<T, FlowyError>;
+typedef LayoutSettingsValue<T> = FlowyResult<T, FlowyError>;
 
 class DatabaseLayoutSettingListener {
   DatabaseLayoutSettingListener(this.viewId);
@@ -30,14 +30,14 @@ class DatabaseLayoutSettingListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateLayoutSettings:
         result.fold(
           (payload) => _settingNotifier?.value =
-              left(DatabaseLayoutSettingPB.fromBuffer(payload)),
+              FlowyResult.success(DatabaseLayoutSettingPB.fromBuffer(payload)),
-          (error) => _settingNotifier?.value = right(error),
+          (error) => _settingNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/row/row_listener.dart

@@ -2,9 +2,9 @@ import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
 import 'package:appflowy_backend/log.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 typedef DidFetchRowCallback = void Function(DidFetchRowPB);
 typedef RowMetaCallback = void Function(RowMetaPB);
@@ -34,7 +34,7 @@ class RowListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateRowMeta:

frontend/appflowy_flutter/lib/plugins/database/application/row/row_meta_listener.dart

@@ -2,9 +2,9 @@ import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
 import 'package:appflowy_backend/log.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 typedef RowMetaCallback = void Function(RowMetaPB);
 
@@ -26,7 +26,7 @@ class RowMetaListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateRowMeta:

frontend/appflowy_flutter/lib/plugins/database/application/row/row_service.dart

@@ -1,7 +1,7 @@
-import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 import '../field/field_info.dart';
 
@@ -12,7 +12,7 @@ class RowBackendService {
 
   final String viewId;
 
-  static Future<Either<RowMetaPB, FlowyError>> createRow({
+  static Future<FlowyResult<RowMetaPB, FlowyError>> createRow({
     required String viewId,
     String? groupId,
     void Function(RowDataBuilder builder)? withCells,
@@ -43,7 +43,7 @@ class RowBackendService {
     return DatabaseEventCreateRow(payload).send();
   }
 
-  Future<Either<RowMetaPB, FlowyError>> createRowBefore(RowId rowId) {
+  Future<FlowyResult<RowMetaPB, FlowyError>> createRowBefore(RowId rowId) {
     return createRow(
       viewId: viewId,
       position: OrderObjectPositionTypePB.Before,
@@ -51,7 +51,7 @@ class RowBackendService {
     );
   }
 
-  Future<Either<RowMetaPB, FlowyError>> createRowAfter(RowId rowId) {
+  Future<FlowyResult<RowMetaPB, FlowyError>> createRowAfter(RowId rowId) {
     return createRow(
       viewId: viewId,
       position: OrderObjectPositionTypePB.After,
@@ -59,7 +59,7 @@ class RowBackendService {
     );
   }
 
-  static Future<Either<RowMetaPB, FlowyError>> getRow({
+  static Future<FlowyResult<RowMetaPB, FlowyError>> getRow({
     required String viewId,
     required String rowId,
   }) {
@@ -70,7 +70,7 @@ class RowBackendService {
     return DatabaseEventGetRowMeta(payload).send();
   }
 
-  Future<Either<RowMetaPB, FlowyError>> getRowMeta(RowId rowId) {
+  Future<FlowyResult<RowMetaPB, FlowyError>> getRowMeta(RowId rowId) {
     final payload = RowIdPB.create()
       ..viewId = viewId
       ..rowId = rowId;
@@ -78,7 +78,7 @@ class RowBackendService {
     return DatabaseEventGetRowMeta(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> updateMeta({
+  Future<FlowyResult<void, FlowyError>> updateMeta({
     required String rowId,
     String? iconURL,
     String? coverURL,
@@ -102,7 +102,7 @@ class RowBackendService {
     return DatabaseEventUpdateRowMeta(payload).send();
   }
 
-  static Future<Either<Unit, FlowyError>> deleteRow(
+  static Future<FlowyResult<void, FlowyError>> deleteRow(
     String viewId,
     RowId rowId,
   ) {
@@ -113,7 +113,7 @@ class RowBackendService {
     return DatabaseEventDeleteRow(payload).send();
   }
 
-  static Future<Either<Unit, FlowyError>> duplicateRow(
+  static Future<FlowyResult<void, FlowyError>> duplicateRow(
     String viewId,
     RowId rowId,
   ) {

frontend/appflowy_flutter/lib/plugins/database/application/setting/setting_listener.dart

@@ -1,13 +1,14 @@
 import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
-import 'package:dartz/dartz.dart';
-import 'package:flowy_infra/notifier.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/setting_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flowy_infra/notifier.dart';
 
-typedef UpdateSettingNotifiedValue = Either<DatabaseViewSettingPB, FlowyError>;
+typedef UpdateSettingNotifiedValue
+    = FlowyResult<DatabaseViewSettingPB, FlowyError>;
 
 class DatabaseSettingListener {
   DatabaseSettingListener({required this.viewId});
@@ -26,14 +27,17 @@ class DatabaseSettingListener {
         DatabaseNotificationListener(objectId: viewId, handler: _handler);
   }
 
-  void _handler(DatabaseNotification ty, Either<Uint8List, FlowyError> result) {
+  void _handler(
+    DatabaseNotification ty,
+    FlowyResult<Uint8List, FlowyError> result,
+  ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateSettings:
         result.fold(
-          (payload) => _updateSettingNotifier?.value = left(
+          (payload) => _updateSettingNotifier?.value = FlowyResult.success(
             DatabaseViewSettingPB.fromBuffer(payload),
           ),
-          (error) => _updateSettingNotifier?.value = right(error),
+          (error) => _updateSettingNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/setting/setting_service.dart

@@ -1,15 +1,15 @@
-import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/setting_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class SettingBackendService {
   const SettingBackendService({required this.viewId});
 
   final String viewId;
 
-  Future<Either<DatabaseViewSettingPB, FlowyError>> getSetting() {
+  Future<FlowyResult<DatabaseViewSettingPB, FlowyError>> getSetting() {
     final payload = DatabaseViewIdPB.create()..value = viewId;
     return DatabaseEventGetDatabaseSetting(payload).send();
   }

frontend/appflowy_flutter/lib/plugins/database/application/share_bloc.dart

@@ -1,12 +1,14 @@
 import 'dart:io';
+
 import 'package:appflowy/workspace/application/settings/share/export_service.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-document/entities.pb.dart';
-import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:freezed_annotation/freezed_annotation.dart';
+import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
-import 'package:dartz/dartz.dart';
+import 'package:freezed_annotation/freezed_annotation.dart';
+
 part 'share_bloc.freezed.dart';
 
 class DatabaseShareBloc extends Bloc<DatabaseShareEvent, DatabaseShareState> {
@@ -35,9 +37,9 @@ class DatabaseShareBloc extends Bloc<DatabaseShareEvent, DatabaseShareState> {
         result.fold(
           (l) {
             _saveCSVToPath(l.data, event.path);
-            return left(unit);
+            return FlowyResult.success(null);
           },
-          (r) => right(r),
+          (r) => FlowyResult.failure(r),
         ),
       ),
     );
@@ -61,6 +63,6 @@ class DatabaseShareState with _$DatabaseShareState {
   const factory DatabaseShareState.initial() = _Initial;
   const factory DatabaseShareState.loading() = _Loading;
   const factory DatabaseShareState.finish(
-    Either<Unit, FlowyError> successOrFail,
+    FlowyResult<void, FlowyError> successOrFail,
   ) = _Finish;
 }

frontend/appflowy_flutter/lib/plugins/database/application/sort/sort_listener.dart

@@ -1,13 +1,14 @@
 import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
-import 'package:flowy_infra/notifier.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flowy_infra/notifier.dart';
 
-typedef SortNotifiedValue = Either<SortChangesetNotificationPB, FlowyError>;
+typedef SortNotifiedValue
+    = FlowyResult<SortChangesetNotificationPB, FlowyError>;
 
 class SortsListener {
   SortsListener({required this.viewId});
@@ -29,14 +30,15 @@ class SortsListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateSort:
         result.fold(
-          (payload) => _notifier?.value =
+          (payload) => _notifier?.value = FlowyResult.success(
-              left(SortChangesetNotificationPB.fromBuffer(payload)),
+            SortChangesetNotificationPB.fromBuffer(payload),
-          (error) => _notifier?.value = right(error),
+          ),
+          (error) => _notifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/application/sort/sort_service.dart

@@ -1,28 +1,28 @@
-import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/log.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/database_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/setting_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class SortBackendService {
   SortBackendService({required this.viewId});
 
   final String viewId;
 
-  Future<Either<List<SortPB>, FlowyError>> getAllSorts() {
+  Future<FlowyResult<List<SortPB>, FlowyError>> getAllSorts() {
     final payload = DatabaseViewIdPB()..value = viewId;
 
     return DatabaseEventGetAllSorts(payload).send().then((result) {
       return result.fold(
-        (repeated) => left(repeated.items),
+        (repeated) => FlowyResult.success(repeated.items),
-        (r) => right(r),
+        (r) => FlowyResult.failure(r),
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> updateSort({
+  Future<FlowyResult<void, FlowyError>> updateSort({
     required String sortId,
     required String fieldId,
     required SortConditionPB condition,
@@ -38,16 +38,16 @@ class SortBackendService {
       ..updateSort = insertSortPayload;
     return DatabaseEventUpdateDatabaseSetting(payload).send().then((result) {
       return result.fold(
-        (l) => left(l),
+        (l) => FlowyResult.success(l),
         (err) {
           Log.error(err);
-          return right(err);
+          return FlowyResult.failure(err);
         },
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> insertSort({
+  Future<FlowyResult<void, FlowyError>> insertSort({
     required String fieldId,
     required SortConditionPB condition,
   }) {
@@ -61,16 +61,16 @@ class SortBackendService {
       ..updateSort = insertSortPayload;
     return DatabaseEventUpdateDatabaseSetting(payload).send().then((result) {
       return result.fold(
-        (l) => left(l),
+        (l) => FlowyResult.success(l),
         (err) {
           Log.error(err);
-          return right(err);
+          return FlowyResult.failure(err);
         },
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> reorderSort({
+  Future<FlowyResult<void, FlowyError>> reorderSort({
     required String fromSortId,
     required String toSortId,
   }) {
@@ -84,7 +84,7 @@ class SortBackendService {
     return DatabaseEventUpdateDatabaseSetting(payload).send();
   }
 
-  Future<Either<Unit, FlowyError>> deleteSort({
+  Future<FlowyResult<void, FlowyError>> deleteSort({
     required String fieldId,
     required String sortId,
   }) {
@@ -98,23 +98,23 @@ class SortBackendService {
 
     return DatabaseEventUpdateDatabaseSetting(payload).send().then((result) {
       return result.fold(
-        (l) => left(l),
+        (l) => FlowyResult.success(l),
         (err) {
           Log.error(err);
-          return right(err);
+          return FlowyResult.failure(err);
         },
       );
     });
   }
 
-  Future<Either<Unit, FlowyError>> deleteAllSorts() {
+  Future<FlowyResult<void, FlowyError>> deleteAllSorts() {
     final payload = DatabaseViewIdPB(value: viewId);
     return DatabaseEventDeleteAllSorts(payload).send().then((result) {
       return result.fold(
-        (l) => left(l),
+        (l) => FlowyResult.success(l),
         (err) {
           Log.error(err);
-          return right(err);
+          return FlowyResult.failure(err);
         },
       );
     });

frontend/appflowy_flutter/lib/plugins/database/application/view/view_listener.dart

@@ -1,19 +1,20 @@
 import 'dart:async';
 import 'dart:typed_data';
+
 import 'package:appflowy/core/notification/grid_notification.dart';
-import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pb.dart';
-import 'package:dartz/dartz.dart';
-import 'package:flowy_infra/notifier.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/notification.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/view_entities.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flowy_infra/notifier.dart';
 
 typedef RowsVisibilityNotifierValue
-    = Either<RowsVisibilityChangePB, FlowyError>;
+    = FlowyResult<RowsVisibilityChangePB, FlowyError>;
 
-typedef NumberOfRowsNotifierValue = Either<RowsChangePB, FlowyError>;
+typedef NumberOfRowsNotifierValue = FlowyResult<RowsChangePB, FlowyError>;
-typedef ReorderAllRowsNotifierValue = Either<List<String>, FlowyError>;
+typedef ReorderAllRowsNotifierValue = FlowyResult<List<String>, FlowyError>;
-typedef SingleRowNotifierValue = Either<ReorderSingleRowPB, FlowyError>;
+typedef SingleRowNotifierValue = FlowyResult<ReorderSingleRowPB, FlowyError>;
 
 class DatabaseViewListener {
   DatabaseViewListener({required this.viewId});
@@ -51,34 +52,38 @@ class DatabaseViewListener {
     _reorderSingleRow?.addPublishListener(onReorderSingleRow);
   }
 
-  void _handler(DatabaseNotification ty, Either<Uint8List, FlowyError> result) {
+  void _handler(
+    DatabaseNotification ty,
+    FlowyResult<Uint8List, FlowyError> result,
+  ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateViewRowsVisibility:
         result.fold(
           (payload) => _rowsVisibility?.value =
-              left(RowsVisibilityChangePB.fromBuffer(payload)),
+              FlowyResult.success(RowsVisibilityChangePB.fromBuffer(payload)),
-          (error) => _rowsVisibility?.value = right(error),
+          (error) => _rowsVisibility?.value = FlowyResult.failure(error),
         );
         break;
       case DatabaseNotification.DidUpdateViewRows:
         result.fold(
-          (payload) =>
+          (payload) => _rowsNotifier?.value =
-              _rowsNotifier?.value = left(RowsChangePB.fromBuffer(payload)),
+              FlowyResult.success(RowsChangePB.fromBuffer(payload)),
-          (error) => _rowsNotifier?.value = right(error),
+          (error) => _rowsNotifier?.value = FlowyResult.failure(error),
         );
         break;
       case DatabaseNotification.DidReorderRows:
         result.fold(
-          (payload) => _reorderAllRows?.value =
+          (payload) => _reorderAllRows?.value = FlowyResult.success(
-              left(ReorderAllRowsPB.fromBuffer(payload).rowOrders),
+            ReorderAllRowsPB.fromBuffer(payload).rowOrders,
-          (error) => _reorderAllRows?.value = right(error),
+          ),
+          (error) => _reorderAllRows?.value = FlowyResult.failure(error),
         );
         break;
       case DatabaseNotification.DidReorderSingleRow:
         result.fold(
           (payload) => _reorderSingleRow?.value =
-              left(ReorderSingleRowPB.fromBuffer(payload)),
+              FlowyResult.success(ReorderSingleRowPB.fromBuffer(payload)),
-          (error) => _reorderSingleRow?.value = right(error),
+          (error) => _reorderSingleRow?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/board/application/board_bloc.dart

@@ -1,8 +1,6 @@
 import 'dart:async';
 import 'dart:collection';
 
-import 'package:flutter/foundation.dart';
-
 import 'package:appflowy/plugins/database/application/defines.dart';
 import 'package:appflowy/plugins/database/application/field/field_info.dart';
 import 'package:appflowy/plugins/database/application/group/group_service.dart';
@@ -12,7 +10,8 @@ import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
 import 'package:appflowy_board/appflowy_board.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 import 'package:protobuf/protobuf.dart' hide FieldInfo;
@@ -20,7 +19,6 @@ import 'package:protobuf/protobuf.dart' hide FieldInfo;
 import '../../application/database_controller.dart';
 import '../../application/field/field_controller.dart';
 import '../../application/row/row_cache.dart';
-
 import 'group_controller.dart';
 
 part 'board_bloc.freezed.dart';
@@ -141,10 +139,10 @@ class BoardBloc extends Bloc<BoardEvent, BoardState> {
             _groupItemStartEditing(group, row, true);
           },
           didReceiveGridUpdate: (DatabasePB grid) {
-            emit(state.copyWith(grid: Some(grid)));
+            emit(state.copyWith(grid: grid));
           },
           didReceiveError: (FlowyError error) {
-            emit(state.copyWith(noneOrError: some(error)));
+            emit(state.copyWith(noneOrError: error));
           },
           didReceiveGroups: (List<GroupPB> groups) {
             final hiddenGroups = _filterHiddenGroups(hideUngrouped, groups);
@@ -450,11 +448,15 @@ class BoardBloc extends Bloc<BoardEvent, BoardState> {
       (grid) {
         databaseController.setIsLoading(false);
         emit(
-          state.copyWith(loadingState: LoadingState.finish(left(unit))),
+          state.copyWith(
+            loadingState: LoadingState.finish(FlowyResult.success(null)),
+          ),
         );
       },
       (err) => emit(
-        state.copyWith(loadingState: LoadingState.finish(right(err))),
+        state.copyWith(
+          loadingState: LoadingState.finish(FlowyResult.failure(err)),
+        ),
       ),
     );
   }
@@ -543,12 +545,12 @@ class BoardEvent with _$BoardEvent {
 class BoardState with _$BoardState {
   const factory BoardState({
     required String viewId,
-    required Option<DatabasePB> grid,
+    required DatabasePB? grid,
     required List<String> groupIds,
     required bool isEditingHeader,
     required bool isEditingRow,
     required LoadingState loadingState,
-    required Option<FlowyError> noneOrError,
+    required FlowyError? noneOrError,
     required BoardLayoutSettingPB? layoutSettings,
     String? editingHeaderId,
     BoardEditingRow? editingRow,
@@ -557,12 +559,12 @@ class BoardState with _$BoardState {
   }) = _BoardState;
 
   factory BoardState.initial(String viewId) => BoardState(
-        grid: none(),
+        grid: null,
         viewId: viewId,
         groupIds: [],
         isEditingHeader: false,
         isEditingRow: false,
-        noneOrError: none(),
+        noneOrError: null,
         loadingState: const LoadingState.loading(),
         layoutSettings: null,
         hiddenGroups: [],

frontend/appflowy_flutter/lib/plugins/database/board/application/group_controller.dart

@@ -1,12 +1,12 @@
-import 'package:appflowy/plugins/database/application/row/row_service.dart';
-import 'package:appflowy_backend/log.dart';
-import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'dart:typed_data';
 
 import 'package:appflowy/core/notification/grid_notification.dart';
+import 'package:appflowy/plugins/database/application/row/row_service.dart';
+import 'package:appflowy_backend/log.dart';
+import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
+import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flowy_infra/notifier.dart';
-import 'package:dartz/dartz.dart';
 import 'package:protobuf/protobuf.dart';
 
 typedef OnGroupError = void Function(FlowyError);
@@ -112,7 +112,8 @@ class GroupController {
   }
 }
 
-typedef UpdateGroupNotifiedValue = Either<GroupRowsNotificationPB, FlowyError>;
+typedef UpdateGroupNotifiedValue
+    = FlowyResult<GroupRowsNotificationPB, FlowyError>;
 
 class SingleGroupListener {
   SingleGroupListener(this.group);
@@ -134,14 +135,14 @@ class SingleGroupListener {
 
   void _handler(
     DatabaseNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case DatabaseNotification.DidUpdateGroupRow:
         result.fold(
           (payload) => _groupNotifier?.value =
-              left(GroupRowsNotificationPB.fromBuffer(payload)),
+              FlowyResult.success(GroupRowsNotificationPB.fromBuffer(payload)),
-          (error) => _groupNotifier?.value = right(error),
+          (error) => _groupNotifier?.value = FlowyResult.failure(error),
         );
         break;
       default:

frontend/appflowy_flutter/lib/plugins/database/board/application/toolbar/board_setting_bloc.dart

@@ -1,4 +1,3 @@
-import 'package:dartz/dartz.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -11,7 +10,7 @@ class BoardSettingBloc extends Bloc<BoardSettingEvent, BoardSettingState> {
       (event, emit) async {
         event.when(
           performAction: (action) {
-            emit(state.copyWith(selectedAction: Some(action)));
+            emit(state.copyWith(selectedAction: action));
           },
         );
       },
@@ -30,11 +29,11 @@ class BoardSettingEvent with _$BoardSettingEvent {
 @freezed
 class BoardSettingState with _$BoardSettingState {
   const factory BoardSettingState({
-    required Option<BoardSettingAction> selectedAction,
+    required BoardSettingAction? selectedAction,
   }) = _BoardSettingState;
 
-  factory BoardSettingState.initial() => BoardSettingState(
+  factory BoardSettingState.initial() => const BoardSettingState(
-        selectedAction: none(),
+        selectedAction: null,
       );
 }
 

frontend/appflowy_flutter/lib/plugins/database/calendar/application/calendar_bloc.dart

@@ -7,8 +7,8 @@ import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/protobuf.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:calendar_view/calendar_view.dart';
-import 'package:dartz/dartz.dart';
 import 'package:fixnum/fixnum.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
@@ -44,15 +44,13 @@ class CalendarBloc extends Bloc<CalendarEvent, CalendarState> {
           },
           didReceiveCalendarSettings: (CalendarLayoutSettingPB settings) {
             // If the field id changed, reload all events
-            state.settings.fold(() => null, (oldSetting) {
+            if (state.settings?.fieldId != settings.fieldId) {
-              if (oldSetting.fieldId != settings.fieldId) {
               _loadAllEvents();
             }
-            });
+            emit(state.copyWith(settings: settings));
-            emit(state.copyWith(settings: Some(settings)));
           },
           didReceiveDatabaseUpdate: (DatabasePB database) {
-            emit(state.copyWith(database: Some(database)));
+            emit(state.copyWith(database: database));
           },
           didLoadAllEvents: (events) {
             final calenderEvents = _calendarEventDataFromEventPBs(events);
@@ -132,21 +130,25 @@ class CalendarBloc extends Bloc<CalendarEvent, CalendarState> {
       (database) {
         databaseController.setIsLoading(false);
         emit(
-          state.copyWith(loadingState: LoadingState.finish(left(unit))),
+          state.copyWith(
+            loadingState: LoadingState.finish(FlowyResult.success(null)),
+          ),
         );
       },
       (err) => emit(
-        state.copyWith(loadingState: LoadingState.finish(right(err))),
+        state.copyWith(
+          loadingState: LoadingState.finish(FlowyResult.failure(err)),
+        ),
       ),
     );
   }
 
   Future<void> _createEvent(DateTime date) async {
-    return state.settings.fold(
+    final settings = state.settings;
-      () {
+    if (settings == null) {
       Log.warn('Calendar settings not found');
-      },
+      return;
-      (settings) async {
+    }
     final dateField = _getCalendarFieldInfo(settings.fieldId);
     if (dateField != null) {
       final newRow = await RowBackendService.createRow(
@@ -169,8 +171,6 @@ class CalendarBloc extends Bloc<CalendarEvent, CalendarState> {
         }
       }
     }
-      },
-    );
   }
 
   Future<void> _moveEvent(CalendarDayEvent event, DateTime date) async {
@@ -412,7 +412,7 @@ class CalendarEvent with _$CalendarEvent {
 @freezed
 class CalendarState with _$CalendarState {
   const factory CalendarState({
-    required Option<DatabasePB> database,
+    required DatabasePB? database,
     // events by row id
     required Events allEvents,
     required Events initialEvents,
@@ -420,19 +420,19 @@ class CalendarState with _$CalendarState {
     CalendarEventData<CalendarDayEvent>? newEvent,
     CalendarEventData<CalendarDayEvent>? updateEvent,
     required List<String> deleteEventIds,
-    required Option<CalendarLayoutSettingPB> settings,
+    required CalendarLayoutSettingPB? settings,
     required LoadingState loadingState,
-    required Option<FlowyError> noneOrError,
+    required FlowyError? noneOrError,
   }) = _CalendarState;
 
-  factory CalendarState.initial() => CalendarState(
+  factory CalendarState.initial() => const CalendarState(
-        database: none(),
+        database: null,
         allEvents: [],
         initialEvents: [],
         deleteEventIds: [],
-        settings: none(),
+        settings: null,
-        noneOrError: none(),
+        noneOrError: null,
-        loadingState: const LoadingState.loading(),
+        loadingState: LoadingState.loading(),
       );
 }
 

frontend/appflowy_flutter/lib/plugins/database/calendar/application/unschedule_event_bloc.dart

@@ -5,7 +5,6 @@ import 'package:appflowy/plugins/database/application/row/row_service.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
-import 'package:dartz/dartz.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -160,13 +159,13 @@ class UnscheduleEventsEvent with _$UnscheduleEventsEvent {
 @freezed
 class UnscheduleEventsState with _$UnscheduleEventsState {
   const factory UnscheduleEventsState({
-    required Option<DatabasePB> database,
+    required DatabasePB? database,
     required List<CalendarEventPB> allEvents,
     required List<CalendarEventPB> unscheduleEvents,
   }) = _UnscheduleEventsState;
 
-  factory UnscheduleEventsState.initial() => UnscheduleEventsState(
+  factory UnscheduleEventsState.initial() => const UnscheduleEventsState(
-        database: none(),
+        database: null,
         allEvents: [],
         unscheduleEvents: [],
       );

frontend/appflowy_flutter/lib/plugins/database/calendar/presentation/calendar_event_card.dart

@@ -145,10 +145,7 @@ class _EventCardState extends State<EventCard> {
       margin: EdgeInsets.zero,
       offset: const Offset(10.0, 0),
       popupBuilder: (BuildContext popoverContext) {
-        final settings = context.watch<CalendarBloc>().state.settings.fold(
+        final settings = context.watch<CalendarBloc>().state.settings;
-              () => null,
-              (layoutSettings) => layoutSettings,
-            );
         if (settings == null) {
           return const SizedBox.shrink();
         }

frontend/appflowy_flutter/lib/plugins/database/calendar/presentation/calendar_page.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/material.dart';
-
 import 'package:appflowy/generated/flowy_svgs.g.dart';
 import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/mobile/presentation/bottom_sheet/bottom_sheet.dart';
@@ -20,12 +18,12 @@ import 'package:flowy_infra/size.dart';
 import 'package:flowy_infra/theme_extension.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
 import 'package:flowy_infra_ui/widget/flowy_tooltip.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../application/row/row_controller.dart';
 import '../../widgets/row/row_detail.dart';
-
 import 'calendar_day.dart';
 import 'layout/sizes.dart';
 import 'toolbar/calendar_setting_bar.dart';
@@ -167,8 +165,7 @@ class _CalendarPageState extends State<CalendarPage> {
                   return _buildCalendar(
                     context,
                     _eventController,
-                    state.settings
+                    state.settings?.firstDayOfWeek ?? 0,
-                        .foldLeft(0, (previous, a) => a.firstDayOfWeek),
                   );
                 },
               );

frontend/appflowy_flutter/lib/plugins/database/grid/application/calculations/calculations_bloc.dart

@@ -2,7 +2,6 @@ import 'package:appflowy/plugins/database/application/calculations/calculations_
 import 'package:appflowy/plugins/database/application/calculations/calculations_service.dart';
 import 'package:appflowy/plugins/database/application/field/field_controller.dart';
 import 'package:appflowy/plugins/database/application/field/field_info.dart';
-import 'package:appflowy/workspace/application/view/view_service.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/calculation_entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/field_settings_entities.pbenum.dart';
 import 'package:bloc/bloc.dart';
@@ -133,7 +132,7 @@ class CalculationsBloc extends Bloc<CalculationsEvent, CalculationsState> {
     final calculationsOrFailure = await _calculationsService.getCalculations();
 
     final RepeatedCalculationsPB? calculations =
-        calculationsOrFailure.getLeftOrNull();
+        calculationsOrFailure.fold((s) => s, (e) => null);
     if (calculations != null) {
       final calculationMap = <String, CalculationPB>{};
       for (final calculation in calculations.items) {

frontend/appflowy_flutter/lib/plugins/database/grid/application/filter/filter_create_bloc.dart

@@ -11,7 +11,7 @@ import 'package:appflowy_backend/protobuf/flowy-database2/number_filter.pb.dart'
 import 'package:appflowy_backend/protobuf/flowy-database2/select_option_filter.pbenum.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/text_filter.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pbserver.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -91,7 +91,9 @@ class GridCreateFilterBloc
     fieldController.addListener(onReceiveFields: _onFieldFn);
   }
 
-  Future<Either<Unit, FlowyError>> _createDefaultFilter(FieldInfo field) async {
+  Future<FlowyResult<void, FlowyError>> _createDefaultFilter(
+    FieldInfo field,
+  ) async {
     final fieldId = field.id;
     switch (field.fieldType) {
       case FieldType.Checkbox:
@@ -144,7 +146,7 @@ class GridCreateFilterBloc
         );
     }
 
-    return left(unit);
+    return FlowyResult.success(null);
   }
 
   @override

frontend/appflowy_flutter/lib/plugins/database/grid/application/grid_bloc.dart

@@ -9,7 +9,7 @@ import 'package:appflowy/plugins/database/grid/presentation/widgets/sort/sort_in
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/protobuf.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -65,7 +65,7 @@ class GridBloc extends Bloc<GridEvent, GridState> {
             databaseController.moveRow(fromRowId: fromRow, toRowId: toRow);
           },
           didReceiveGridUpdate: (grid) {
-            emit(state.copyWith(grid: Some(grid)));
+            emit(state.copyWith(grid: grid));
           },
           didReceiveFieldUpdate: (fields) {
             emit(
@@ -147,11 +147,15 @@ class GridBloc extends Bloc<GridEvent, GridState> {
       (grid) {
         databaseController.setIsLoading(false);
         emit(
-          state.copyWith(loadingState: LoadingState.finish(left(unit))),
+          state.copyWith(
+            loadingState: LoadingState.finish(FlowyResult.success(null)),
+          ),
         );
       },
       (err) => emit(
-        state.copyWith(loadingState: LoadingState.finish(right(err))),
+        state.copyWith(
+          loadingState: LoadingState.finish(FlowyResult.failure(err)),
+        ),
       ),
     );
   }
@@ -186,7 +190,7 @@ class GridEvent with _$GridEvent {
 class GridState with _$GridState {
   const factory GridState({
     required String viewId,
-    required Option<DatabasePB> grid,
+    required DatabasePB? grid,
     required List<FieldInfo> fields,
     required List<RowInfo> rowInfos,
     required int rowCount,
@@ -204,7 +208,7 @@ class GridState with _$GridState {
         rowInfos: [],
         rowCount: 0,
         createdRow: null,
-        grid: none(),
+        grid: null,
         viewId: viewId,
         reorderable: true,
         loadingState: const LoadingState.loading(),

frontend/appflowy_flutter/lib/plugins/database/grid/application/sort/sort_create_bloc.dart

@@ -4,13 +4,12 @@ import 'package:appflowy/plugins/database/application/field/field_info.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pbenum.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/sort_entities.pbserver.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pbserver.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
 import '../../../application/field/field_controller.dart';
 import '../../../application/sort/sort_service.dart';
-
 import 'util.dart';
 
 part 'sort_create_bloc.freezed.dart';
@@ -88,7 +87,9 @@ class CreateSortBloc extends Bloc<CreateSortEvent, CreateSortState> {
     fieldController.addListener(onReceiveFields: _onFieldFn);
   }
 
-  Future<Either<Unit, FlowyError>> _createDefaultSort(FieldInfo field) async {
+  Future<FlowyResult<void, FlowyError>> _createDefaultSort(
+    FieldInfo field,
+  ) async {
     final result = await _sortBackendSvc.insertSort(
       fieldId: field.id,
       condition: SortConditionPB.Ascending,

frontend/appflowy_flutter/lib/plugins/database/grid/presentation/widgets/header/type_option/select/select_option.dart

@@ -1,17 +1,17 @@
 import 'package:appflowy/generated/flowy_svgs.g.dart';
+import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/database/application/field/type_option/select_option_type_option_bloc.dart';
 import 'package:appflowy/plugins/database/application/field/type_option/select_type_option_actions.dart';
 import 'package:appflowy/plugins/database/grid/presentation/layout/sizes.dart';
 import 'package:appflowy/plugins/database/widgets/cell_editor/extension.dart';
 import 'package:appflowy_backend/protobuf/flowy-database2/select_option_entities.pb.dart';
 import 'package:appflowy_popover/appflowy_popover.dart';
+import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra/theme_extension.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
 import 'package:flowy_infra_ui/style_widget/hover.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
-import 'package:easy_localization/easy_localization.dart';
-import 'package:appflowy/generated/locale_keys.g.dart';
 
 import 'select_option_editor.dart';
 
@@ -218,7 +218,7 @@ class _CreateOptionTextFieldState extends State<CreateOptionTextField> {
   Widget build(BuildContext context) {
     return BlocBuilder<SelectOptionTypeOptionBloc, SelectOptionTypeOptionState>(
       builder: (context, state) {
-        final text = state.newOptionName.foldRight("", (a, previous) => a);
+        final text = state.newOptionName ?? '';
         return Padding(
           padding: const EdgeInsets.symmetric(horizontal: 14.0),
           child: FlowyTextField(

frontend/appflowy_flutter/lib/plugins/database/tab_bar/tab_bar_view.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/material.dart';
-
 import 'package:appflowy/plugins/database/application/database_controller.dart';
 import 'package:appflowy/plugins/database/application/tab_bar_bloc.dart';
 import 'package:appflowy/plugins/database/grid/presentation/layout/sizes.dart';
@@ -12,6 +10,7 @@ import 'package:appflowy/workspace/presentation/widgets/view_title_bar.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:flowy_infra_ui/widget/spacing.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 import 'desktop/tab_bar_header.dart';
@@ -221,12 +220,11 @@ class DatabasePluginWidgetBuilder extends PluginWidgetBuilder {
   @override
   Widget buildWidget({PluginContext? context, required bool shrinkWrap}) {
     notifier.isDeleted.addListener(() {
-      notifier.isDeleted.value.fold(() => null, (deletedView) {
+      final deletedView = notifier.isDeleted.value;
-        if (deletedView.hasIndex()) {
+      if (deletedView != null && deletedView.hasIndex()) {
         context?.onDeleted(notifier.view, deletedView.index);
       }
     });
-    });
     return DatabaseTabBarView(
       key: ValueKey(notifier.view.id),
       view: notifier.view,

frontend/appflowy_flutter/lib/plugins/database/widgets/cell_editor/mobile_select_option_editor.dart

@@ -260,17 +260,15 @@ class _OptionList extends StatelessWidget {
         final List<Widget> cells = [];
 
         // create an option cell
-        state.createOption.fold(
+        final createOption = state.createOption;
-          () => null,
+        if (createOption != null) {
-          (createOption) {
           cells.add(
             _CreateOptionCell(
               optionName: createOption,
               onTap: () => onCreateOption(createOption),
             ),
           );
-          },
+        }
-        );
 
         cells.addAll(
           state.options.map(

frontend/appflowy_flutter/lib/plugins/database/widgets/cell_editor/select_option_editor.dart

@@ -12,11 +12,11 @@ import 'package:flowy_infra_ui/style_widget/hover.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
+import '../../application/cell/bloc/select_option_editor_bloc.dart';
 import '../../grid/presentation/layout/sizes.dart';
 import '../../grid/presentation/widgets/common/type_option_separator.dart';
 import '../../grid/presentation/widgets/header/type_option/select/select_option_editor.dart';
 import 'extension.dart';
-import '../../application/cell/bloc/select_option_editor_bloc.dart';
 import 'select_option_text_field.dart';
 
 const double _editorPanelWidth = 300;
@@ -95,12 +95,10 @@ class _OptionList extends StatelessWidget {
           ),
         ];
 
-        state.createOption.fold(
+        final createOption = state.createOption;
-          () => null,
+        if (createOption != null) {
-          (createOption) {
           cells.add(_CreateOptionCell(name: createOption));
-          },
+        }
-        );
 
         return ListView.separated(
           shrinkWrap: true,

frontend/appflowy_flutter/lib/plugins/document/application/doc_bloc.dart

@@ -1,7 +1,5 @@
 import 'dart:async';
 
-import 'package:flutter/foundation.dart';
-
 import 'package:appflowy/plugins/document/application/doc_service.dart';
 import 'package:appflowy/plugins/document/application/document_data_pb_extension.dart';
 import 'package:appflowy/plugins/document/application/editor_transaction_adapter.dart';
@@ -23,7 +21,8 @@ import 'package:appflowy_editor/appflowy_editor.dart'
         Selection,
         Position,
         paragraphNode;
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -77,25 +76,28 @@ class DocumentBloc extends Bloc<DocumentEvent, DocumentState> {
         _onViewChanged();
         _onDocumentChanged();
         await editorState.fold(
-          (l) async => emit(
+          (s) async {
-            state.copyWith(
-              error: l,
-              editorState: null,
-              isLoading: false,
-            ),
-          ),
-          (r) async {
             final result = await getIt<AuthService>().getUser();
-            final userProfilePB = result.fold((l) => null, (r) => r);
+            final userProfilePB = result.fold(
+              (s) => s,
+              (e) => null,
+            );
             emit(
               state.copyWith(
                 error: null,
-                editorState: r,
+                editorState: s,
                 isLoading: false,
                 userProfilePB: userProfilePB,
               ),
             );
           },
+          (f) async => emit(
+            state.copyWith(
+              error: f,
+              editorState: null,
+              isLoading: false,
+            ),
+          ),
         );
       },
       moveToTrash: () async {
@@ -124,13 +126,12 @@ class DocumentBloc extends Bloc<DocumentEvent, DocumentState> {
   void _onViewChanged() {
     _viewListener.start(
       onViewMoveToTrash: (r) {
-        r.swap().map((r) => add(const DocumentEvent.moveToTrash()));
+        r.map((r) => add(const DocumentEvent.moveToTrash()));
       },
       onViewDeleted: (r) {
-        r.swap().map((r) => add(const DocumentEvent.moveToTrash()));
+        r.map((r) => add(const DocumentEvent.moveToTrash()));
       },
-      onViewRestored: (r) =>
+      onViewRestored: (r) => r.map((r) => add(const DocumentEvent.restore())),
-          r.swap().map((r) => add(const DocumentEvent.restore())),
     );
   }
 
@@ -150,11 +151,11 @@ class DocumentBloc extends Bloc<DocumentEvent, DocumentState> {
   }
 
   /// Fetch document
-  Future<Either<FlowyError, EditorState?>> _fetchDocumentState() async {
+  Future<FlowyResult<EditorState?, FlowyError>> _fetchDocumentState() async {
     final result = await _documentService.openDocument(viewId: view.id);
     return result.fold(
-      (l) => left(l),
+      (s) async => FlowyResult.success(await _initAppFlowyEditorState(s)),
-      (r) async => right(await _initAppFlowyEditorState(r)),
+      (e) => FlowyResult.failure(e),
     );
   }
 

frontend/appflowy_flutter/lib/plugins/document/application/doc_service.dart

@@ -2,56 +2,56 @@ import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-document/entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class DocumentService {
   // unused now.
-  Future<Either<FlowyError, Unit>> createDocument({
+  Future<FlowyResult<void, FlowyError>> createDocument({
     required ViewPB view,
   }) async {
     final canOpen = await openDocument(viewId: view.id);
-    if (canOpen.isRight()) {
+    if (canOpen.isSuccess()) {
-      return const Right(unit);
+      return FlowyResult.success(null);
     }
     final payload = CreateDocumentPayloadPB()..documentId = view.id;
     final result = await DocumentEventCreateDocument(payload).send();
-    return result.swap();
+    return result;
   }
 
-  Future<Either<FlowyError, DocumentDataPB>> openDocument({
+  Future<FlowyResult<DocumentDataPB, FlowyError>> openDocument({
     required String viewId,
   }) async {
     final payload = OpenDocumentPayloadPB()..documentId = viewId;
     final result = await DocumentEventOpenDocument(payload).send();
-    return result.swap();
+    return result;
   }
 
-  Future<Either<FlowyError, BlockPB>> getBlockFromDocument({
+  Future<FlowyResult<BlockPB, FlowyError>> getBlockFromDocument({
     required DocumentDataPB document,
     required String blockId,
   }) async {
     final block = document.blocks[blockId];
 
     if (block != null) {
-      return right(block);
+      return FlowyResult.success(block);
     }
 
-    return left(
+    return FlowyResult.failure(
       FlowyError(
         msg: 'Block($blockId) not found in Document(${document.pageId})',
       ),
     );
   }
 
-  Future<Either<FlowyError, Unit>> closeDocument({
+  Future<FlowyResult<void, FlowyError>> closeDocument({
     required ViewPB view,
   }) async {
     final payload = CloseDocumentPayloadPB()..documentId = view.id;
     final result = await DocumentEventCloseDocument(payload).send();
-    return result.swap();
+    return result;
   }
 
-  Future<Either<FlowyError, Unit>> applyAction({
+  Future<FlowyResult<void, FlowyError>> applyAction({
     required String documentId,
     required Iterable<BlockActionPB> actions,
   }) async {
@@ -60,7 +60,7 @@ class DocumentService {
       actions: actions,
     );
     final result = await DocumentEventApplyAction(payload).send();
-    return result.swap();
+    return result;
   }
 
   /// Creates a new external text.
@@ -68,7 +68,7 @@ class DocumentService {
   /// Normally, it's used to the block that needs sync long text.
   ///
   /// the delta parameter is the json representation of the delta.
-  Future<Either<FlowyError, Unit>> createExternalText({
+  Future<FlowyResult<void, FlowyError>> createExternalText({
     required String documentId,
     required String textId,
     String? delta,
@@ -79,7 +79,7 @@ class DocumentService {
       delta: delta,
     );
     final result = await DocumentEventCreateText(payload).send();
-    return result.swap();
+    return result;
   }
 
   /// Updates the external text.
@@ -87,7 +87,7 @@ class DocumentService {
   /// this function is compatible with the [createExternalText] function.
   ///
   /// the delta parameter is the json representation of the delta too.
-  Future<Either<FlowyError, Unit>> updateExternalText({
+  Future<FlowyResult<void, FlowyError>> updateExternalText({
     required String documentId,
     required String textId,
     String? delta,
@@ -98,11 +98,11 @@ class DocumentService {
       delta: delta,
     );
     final result = await DocumentEventApplyTextDeltaEvent(payload).send();
-    return result.swap();
+    return result;
   }
 
   /// Upload a file to the cloud storage.
-  Future<Either<FlowyError, UploadedFilePB>> uploadFile({
+  Future<FlowyResult<UploadedFilePB, FlowyError>> uploadFile({
     required String localFilePath,
     bool isAsync = true,
   }) async {
@@ -114,14 +114,14 @@ class DocumentService {
         isAsync: isAsync,
       );
       final result = await DocumentEventUploadFile(payload).send();
-      return result.swap();
+      return result;
     }, (r) async {
-      return left(FlowyError(msg: 'Workspace not found'));
+      return FlowyResult.failure(FlowyError(msg: 'Workspace not found'));
     });
   }
 
   /// Download a file from the cloud storage.
-  Future<Either<FlowyError, Unit>> downloadFile({
+  Future<FlowyResult<void, FlowyError>> downloadFile({
     required String url,
   }) async {
     final workspace = await FolderEventReadCurrentWorkspace().send();
@@ -130,9 +130,9 @@ class DocumentService {
         url: url,
       );
       final result = await DocumentEventDownloadFile(payload).send();
-      return result.swap();
+      return result;
     }, (r) async {
-      return left(FlowyError(msg: 'Workspace not found'));
+      return FlowyResult.failure(FlowyError(msg: 'Workspace not found'));
     });
   }
 }

frontend/appflowy_flutter/lib/plugins/document/application/share_bloc.dart

@@ -4,7 +4,7 @@ import 'package:appflowy/workspace/application/export/document_exporter.dart';
 import 'package:appflowy_backend/protobuf/flowy-document/entities.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -28,8 +28,9 @@ class DocShareBloc extends Bloc<DocShareEvent, DocShareState> {
     emit(
       DocShareState.finish(
         result.fold(
-          (error) => right(error),
+          (markdown) =>
-          (markdown) => left(_saveMarkdownToPath(markdown, event.path)),
+              FlowyResult.success(_saveMarkdownToPath(markdown, event.path)),
+          (error) => FlowyResult.failure(error),
         ),
       ),
     );
@@ -55,6 +56,6 @@ class DocShareState with _$DocShareState {
   const factory DocShareState.initial() = _Initial;
   const factory DocShareState.loading() = _Loading;
   const factory DocShareState.finish(
-    Either<ExportDataPB, FlowyError> successOrFail,
+    FlowyResult<ExportDataPB, FlowyError> successOrFail,
   ) = _Finish;
 }

frontend/appflowy_flutter/lib/plugins/document/document.dart

@@ -1,14 +1,12 @@
 library document_plugin;
 
-import 'package:flutter/material.dart';
-
 import 'package:appflowy/generated/flowy_svgs.g.dart';
 import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/document/document_page.dart';
+import 'package:appflowy/plugins/document/presentation/favorite/favorite_button.dart';
 import 'package:appflowy/plugins/document/presentation/more/cubit/document_appearance_cubit.dart';
 import 'package:appflowy/plugins/document/presentation/more/more_button.dart';
 import 'package:appflowy/plugins/document/presentation/share/share_button.dart';
-import 'package:appflowy/plugins/document/presentation/favorite/favorite_button.dart';
 import 'package:appflowy/plugins/util.dart';
 import 'package:appflowy/startup/plugin/plugin.dart';
 import 'package:appflowy/workspace/presentation/home/home_stack.dart';
@@ -18,6 +16,7 @@ import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
 class DocumentPluginBuilder extends PluginBuilder {
@@ -90,14 +89,10 @@ class DocumentPluginWidgetBuilder extends PluginWidgetBuilder
   @override
   Widget buildWidget({PluginContext? context, required bool shrinkWrap}) {
     notifier.isDeleted.addListener(() {
-      notifier.isDeleted.value.fold(
+      final deletedView = notifier.isDeleted.value;
-        () => null,
+      if (deletedView != null && deletedView.hasIndex()) {
-        (deletedView) {
-          if (deletedView.hasIndex()) {
         deletedViewIndex = deletedView.index;
       }
-        },
-      );
     });
 
     return BlocBuilder<DocumentAppearanceCubit, DocumentAppearance>(

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/base/built_in_page_widget.dart

@@ -1,23 +1,22 @@
 import 'package:appflowy/generated/flowy_svgs.g.dart';
+import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/document/presentation/editor_plugins/plugins.dart';
 import 'package:appflowy/startup/plugin/plugin.dart';
 import 'package:appflowy/startup/startup.dart';
 import 'package:appflowy/workspace/application/tabs/tabs_bloc.dart';
+import 'package:appflowy/workspace/application/view/view_ext.dart';
 import 'package:appflowy/workspace/application/view/view_service.dart';
 import 'package:appflowy/workspace/presentation/widgets/pop_up_action.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pbserver.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
 import 'package:appflowy_editor/appflowy_editor.dart';
-import 'package:dartz/dartz.dart' as dartz;
+import 'package:appflowy_popover/appflowy_popover.dart';
+import 'package:appflowy_result/appflowy_result.dart';
+import 'package:easy_localization/easy_localization.dart';
+import 'package:flowy_infra_ui/style_widget/icon_button.dart';
 import 'package:flowy_infra_ui/style_widget/text.dart';
 import 'package:flowy_infra_ui/widget/spacing.dart';
 import 'package:flutter/material.dart';
-import 'package:appflowy/generated/locale_keys.g.dart';
-import 'package:easy_localization/easy_localization.dart';
-
-import 'package:appflowy/workspace/application/view/view_ext.dart';
-import 'package:appflowy_popover/appflowy_popover.dart';
-import 'package:flowy_infra_ui/style_widget/icon_button.dart';
 
 class BuiltInPageWidget extends StatefulWidget {
   const BuiltInPageWidget({
@@ -36,7 +35,8 @@ class BuiltInPageWidget extends StatefulWidget {
 }
 
 class _BuiltInPageWidgetState extends State<BuiltInPageWidget> {
-  late Future<dartz.Either<FlowyError, ViewPB>> future;
+  late Future<FlowyResult<ViewPB, FlowyError>> future;
+
   final focusNode = FocusNode();
 
   String get parentViewId => widget.node.attributes[DatabaseBlockKeys.parentID];
@@ -45,13 +45,9 @@ class _BuiltInPageWidgetState extends State<BuiltInPageWidget> {
   @override
   void initState() {
     super.initState();
-    future = ViewBackendService()
+    future = ViewBackendService().getChildView(
-        .getChildView(
       parentViewId: parentViewId,
       childViewId: childViewId,
-        )
-        .then(
-          (value) => value.swap(),
     );
   }
 
@@ -63,9 +59,9 @@ class _BuiltInPageWidgetState extends State<BuiltInPageWidget> {
 
   @override
   Widget build(BuildContext context) {
-    return FutureBuilder<dartz.Either<FlowyError, ViewPB>>(
+    return FutureBuilder<FlowyResult<ViewPB, FlowyError>>(
       builder: (context, snapshot) {
-        final page = snapshot.data?.toOption().toNullable();
+        final page = snapshot.data?.toNullable();
         if (snapshot.hasData && page != null) {
           return _build(context, page);
         }

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/base/insert_page_command.dart

@@ -87,7 +87,7 @@ extension InsertDatabase on EditorState {
     // get the database id that the view is associated with
     final databaseId = await DatabaseViewBackendService(viewId: view.id)
         .getDatabaseId()
-        .then((value) => value.swap().toOption().toNullable());
+        .then((value) => value.toNullable());
 
     if (databaseId == null) {
       throw StateError(
@@ -101,7 +101,7 @@ extension InsertDatabase on EditorState {
       name: "$prefix ${view.name}",
       layoutType: view.layout,
       databaseId: databaseId,
-    ).then((value) => value.swap().toOption().toNullable());
+    ).then((value) => value.toNullable());
 
     if (ref == null) {
       throw FlowyError(

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/database/inline_database_menu_item.dart

@@ -25,7 +25,7 @@ SelectionMenuItem inlineGridMenuItem(DocumentBloc documentBloc) =>
           name: LocaleKeys.menuAppHeader_defaultNewPageName.tr(),
           layoutType: ViewLayoutPB.Grid,
         );
-        value.swap().map((r) => editorState.insertInlinePage(parentViewId, r));
+        value.map((r) => editorState.insertInlinePage(parentViewId, r));
       },
     );
 
@@ -46,7 +46,7 @@ SelectionMenuItem inlineBoardMenuItem(DocumentBloc documentBloc) =>
           name: LocaleKeys.menuAppHeader_defaultNewPageName.tr(),
           layoutType: ViewLayoutPB.Board,
         );
-        value.swap().map((r) => editorState.insertInlinePage(parentViewId, r));
+        value.map((r) => editorState.insertInlinePage(parentViewId, r));
       },
     );
 
@@ -68,6 +68,6 @@ SelectionMenuItem inlineCalendarMenuItem(DocumentBloc documentBloc) =>
           name: LocaleKeys.menuAppHeader_defaultNewPageName.tr(),
           layoutType: ViewLayoutPB.Calendar,
         );
-        value.swap().map((r) => editorState.insertInlinePage(parentViewId, r));
+        value.map((r) => editorState.insertInlinePage(parentViewId, r));
       },
     );

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/header/custom_cover_picker.dart

@@ -1,18 +1,18 @@
 import 'dart:io';
+
 import 'package:appflowy/generated/flowy_svgs.g.dart';
 import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/document/presentation/editor_plugins/header/custom_cover_picker_bloc.dart';
 import 'package:easy_localization/easy_localization.dart';
-import 'package:flowy_infra_ui/style_widget/snap_bar.dart';
-import 'package:flowy_infra_ui/widget/spacing.dart';
-import 'package:flutter_bloc/flutter_bloc.dart';
-
 import 'package:flowy_infra/size.dart';
 import 'package:flowy_infra_ui/style_widget/button.dart';
+import 'package:flowy_infra_ui/style_widget/snap_bar.dart';
 import 'package:flowy_infra_ui/style_widget/text.dart';
 import 'package:flowy_infra_ui/style_widget/text_field.dart';
 import 'package:flowy_infra_ui/widget/rounded_button.dart';
+import 'package:flowy_infra_ui/widget/spacing.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
 
 class CoverImagePicker extends StatefulWidget {
   const CoverImagePicker({
@@ -37,12 +37,13 @@ class _CoverImagePickerState extends State<CoverImagePicker> {
       child: BlocListener<CoverImagePickerBloc, CoverImagePickerState>(
         listener: (context, state) {
           if (state is NetworkImagePicked) {
-            state.successOrFail.isRight()
+            state.successOrFail.fold(
-                ? showSnapBar(
+              (s) {},
+              (e) => showSnapBar(
                 context,
                 LocaleKeys.document_plugins_cover_invalidImageUrl.tr(),
-                  )
+              ),
-                : null;
+            );
           }
           if (state is Done) {
             state.successOrFail.fold(

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/header/custom_cover_picker_bloc.dart

@@ -4,7 +4,7 @@ import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/startup/startup.dart';
 import 'package:appflowy/workspace/application/settings/prelude.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra/file_picker/file_picker_service.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
@@ -36,11 +36,15 @@ class CoverImagePickerBloc
             emit(const CoverImagePickerState.loading());
             final validateImage = await _validateURL(urlSubmit.path);
             if (validateImage) {
-              emit(CoverImagePickerState.networkImage(left(urlSubmit.path)));
+              emit(
+                CoverImagePickerState.networkImage(
+                  FlowyResult.success(urlSubmit.path),
+                ),
+              );
             } else {
               emit(
                 CoverImagePickerState.networkImage(
-                  right(
+                  FlowyResult.failure(
                     FlowyError(
                       msg: LocaleKeys.document_plugins_cover_couldNotFetchImage
                           .tr(),
@@ -65,11 +69,11 @@ class CoverImagePickerBloc
             emit(const CoverImagePickerState.loading());
             final saveImage = await _saveToGallery(saveToGallery.previousState);
             if (saveImage != null) {
-              emit(CoverImagePickerState.done(left(saveImage)));
+              emit(CoverImagePickerState.done(FlowyResult.success(saveImage)));
             } else {
               emit(
                 CoverImagePickerState.done(
-                  right(
+                  FlowyResult.failure(
                     FlowyError(
                       msg: LocaleKeys.document_plugins_cover_imageSavingFailed
                           .tr(),
@@ -208,11 +212,11 @@ class CoverImagePickerState with _$CoverImagePickerState {
   const factory CoverImagePickerState.initial() = Initial;
   const factory CoverImagePickerState.loading() = Loading;
   const factory CoverImagePickerState.networkImage(
-    Either<String, FlowyError> successOrFail,
+    FlowyResult<String, FlowyError> successOrFail,
   ) = NetworkImagePicked;
   const factory CoverImagePickerState.fileImage(String path) = FileImagePicked;
 
   const factory CoverImagePickerState.done(
-    Either<List<String>, FlowyError> successOrFail,
+    FlowyResult<List<String>, FlowyError> successOrFail,
   ) = Done;
 }

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/image/image_util.dart

@@ -43,13 +43,13 @@ Future<(String? path, String? errorMessage)> saveImageToCloudStorage(
     isAsync: false,
   );
   return result.fold(
-    (l) => (null, l.msg),
+    (s) async {
-    (r) async {
       await CustomImageCacheManager().putFile(
-        r.url,
+        s.url,
         File(localImagePath).readAsBytesSync(),
       );
-      return (r.url, null);
+      return (s.url, null);
     },
+    (e) => (null, e.msg),
   );
 }

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/image/open_ai_image_widget.dart

@@ -4,7 +4,7 @@ import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/document/presentation/editor_plugins/openai/service/error.dart';
 import 'package:appflowy/plugins/document/presentation/editor_plugins/openai/service/openai_client.dart';
 import 'package:appflowy/startup/startup.dart';
-import 'package:dartz/dartz.dart' hide State;
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
 import 'package:flutter/material.dart';
@@ -22,7 +22,7 @@ class OpenAIImageWidget extends StatefulWidget {
 }
 
 class _OpenAIImageWidgetState extends State<OpenAIImageWidget> {
-  Future<Either<OpenAIError, List<String>>>? future;
+  Future<FlowyResult<List<String>, OpenAIError>>? future;
   String query = '';
 
   @override
@@ -63,19 +63,12 @@ class _OpenAIImageWidgetState extends State<OpenAIImageWidget> {
                   return const CircularProgressIndicator.adaptive();
                 }
                 return data.fold(
-                  (l) => Center(
+                  (s) => GridView.count(
-                    child: FlowyText(
-                      l.message,
-                      maxLines: 3,
-                      textAlign: TextAlign.center,
-                    ),
-                  ),
-                  (r) => GridView.count(
                     crossAxisCount: 3,
                     mainAxisSpacing: 16.0,
                     crossAxisSpacing: 10.0,
                     childAspectRatio: 4 / 3,
-                    children: r
+                    children: s
                         .map(
                           (e) => GestureDetector(
                             onTap: () => widget.onSelectNetworkImage(e),
@@ -84,6 +77,13 @@ class _OpenAIImageWidgetState extends State<OpenAIImageWidget> {
                         )
                         .toList(),
                   ),
+                  (e) => Center(
+                    child: FlowyText(
+                      e.message,
+                      maxLines: 3,
+                      textAlign: TextAlign.center,
+                    ),
+                  ),
                 );
               },
             ),

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/image/stability_ai_image_widget.dart

@@ -6,7 +6,7 @@ import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/document/presentation/editor_plugins/stability_ai/stability_ai_client.dart';
 import 'package:appflowy/plugins/document/presentation/editor_plugins/stability_ai/stability_ai_error.dart';
 import 'package:appflowy/startup/startup.dart';
-import 'package:dartz/dartz.dart' hide State;
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:flowy_infra/uuid.dart';
 import 'package:flowy_infra_ui/flowy_infra_ui.dart';
@@ -27,7 +27,7 @@ class StabilityAIImageWidget extends StatefulWidget {
 }
 
 class _StabilityAIImageWidgetState extends State<StabilityAIImageWidget> {
-  Future<Either<StabilityAIRequestError, List<String>>>? future;
+  Future<FlowyResult<List<String>, StabilityAIRequestError>>? future;
   String query = '';
 
   @override
@@ -70,19 +70,12 @@ class _StabilityAIImageWidgetState extends State<StabilityAIImageWidget> {
                   return const CircularProgressIndicator.adaptive();
                 }
                 return data.fold(
-                  (l) => Center(
+                  (s) => GridView.count(
-                    child: FlowyText(
-                      l.message,
-                      maxLines: 3,
-                      textAlign: TextAlign.center,
-                    ),
-                  ),
-                  (r) => GridView.count(
                     crossAxisCount: 3,
                     mainAxisSpacing: 16.0,
                     crossAxisSpacing: 10.0,
                     childAspectRatio: 4 / 3,
-                    children: r.map(
+                    children: s.map(
                       (e) {
                         final base64Image = base64Decode(e);
                         return GestureDetector(
@@ -100,6 +93,13 @@ class _StabilityAIImageWidgetState extends State<StabilityAIImageWidget> {
                       },
                     ).toList(),
                   ),
+                  (e) => Center(
+                    child: FlowyText(
+                      e.message,
+                      maxLines: 3,
+                      textAlign: TextAlign.center,
+                    ),
+                  ),
                 );
               },
             ),

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/image/upload_image_menu.dart

@@ -76,12 +76,12 @@ class _UploadImageMenuState extends State<UploadImageMenu> {
     UserBackendService.getCurrentUserProfile().then(
       (value) {
         final supportOpenAI = value.fold(
-          (l) => false,
+          (s) => s.openaiKey.isNotEmpty,
-          (r) => r.openaiKey.isNotEmpty,
+          (e) => false,
         );
         final supportStabilityAI = value.fold(
-          (l) => false,
+          (s) => s.stabilityAiKey.isNotEmpty,
-          (r) => r.stabilityAiKey.isNotEmpty,
+          (e) => false,
         );
         if (supportOpenAI != this.supportOpenAI ||
             supportStabilityAI != this.supportStabilityAI) {

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/link_preview/link_preview_cache.dart

@@ -12,7 +12,7 @@ class LinkPreviewDataCache implements LinkPreviewDataCacheInterface {
       url,
       (value) => LinkPreviewData.fromJson(jsonDecode(value)),
     );
-    return option.fold(() => null, (a) => a);
+    return option;
   }
 
   @override

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/mention/mention_page_block.dart

@@ -126,7 +126,7 @@ class _MentionPageBlockState extends State<MentionPageBlock> {
 
   Future<ViewPB?> fetchView(String pageId) async {
     final view = await ViewBackendService.getView(pageId).then(
-      (value) => value.swap().toOption().toNullable(),
+      (value) => value.toNullable(),
     );
 
     if (view == null) {

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/openai/service/openai_client.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:appflowy/plugins/document/presentation/editor_plugins/openai/service/text_edit.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:http/http.dart' as http;
 
 import 'error.dart';
@@ -33,7 +33,7 @@ abstract class OpenAIRepository {
   /// [maxTokens] is the maximum number of tokens to generate
   /// [temperature] is the temperature of the model
   ///
-  Future<Either<OpenAIError, TextCompletionResponse>> getCompletions({
+  Future<FlowyResult<TextCompletionResponse, OpenAIError>> getCompletions({
     required String prompt,
     String? suffix,
     int maxTokens = 2048,
@@ -58,7 +58,7 @@ abstract class OpenAIRepository {
   /// [instruction] is the instruction text
   /// [temperature] is the temperature of the model
   ///
-  Future<Either<OpenAIError, TextEditResponse>> getEdits({
+  Future<FlowyResult<TextEditResponse, OpenAIError>> getEdits({
     required String input,
     required String instruction,
     double temperature = 0.3,
@@ -70,7 +70,7 @@ abstract class OpenAIRepository {
   /// [n] is the number of images to generate
   ///
   /// the result is a list of urls
-  Future<Either<OpenAIError, List<String>>> generateImage({
+  Future<FlowyResult<List<String>, OpenAIError>> generateImage({
     required String prompt,
     int n = 1,
   });
@@ -91,7 +91,7 @@ class HttpOpenAIRepository implements OpenAIRepository {
       };
 
   @override
-  Future<Either<OpenAIError, TextCompletionResponse>> getCompletions({
+  Future<FlowyResult<TextCompletionResponse, OpenAIError>> getCompletions({
     required String prompt,
     String? suffix,
     int maxTokens = 2048,
@@ -113,7 +113,7 @@ class HttpOpenAIRepository implements OpenAIRepository {
     );
 
     if (response.statusCode == 200) {
-      return Right(
+      return FlowyResult.success(
         TextCompletionResponse.fromJson(
           json.decode(
             utf8.decode(response.bodyBytes),
@@ -121,7 +121,9 @@ class HttpOpenAIRepository implements OpenAIRepository {
         ),
       );
     } else {
-      return Left(OpenAIError.fromJson(json.decode(response.body)['error']));
+      return FlowyResult.failure(
+        OpenAIError.fromJson(json.decode(response.body)['error']),
+      );
     }
   }
 
@@ -206,7 +208,7 @@ class HttpOpenAIRepository implements OpenAIRepository {
   }
 
   @override
-  Future<Either<OpenAIError, TextEditResponse>> getEdits({
+  Future<FlowyResult<TextEditResponse, OpenAIError>> getEdits({
     required String input,
     required String instruction,
     double temperature = 0.3,
@@ -227,7 +229,7 @@ class HttpOpenAIRepository implements OpenAIRepository {
     );
 
     if (response.statusCode == 200) {
-      return Right(
+      return FlowyResult.success(
         TextEditResponse.fromJson(
           json.decode(
             utf8.decode(response.bodyBytes),
@@ -235,12 +237,14 @@ class HttpOpenAIRepository implements OpenAIRepository {
         ),
       );
     } else {
-      return Left(OpenAIError.fromJson(json.decode(response.body)['error']));
+      return FlowyResult.failure(
+        OpenAIError.fromJson(json.decode(response.body)['error']),
+      );
     }
   }
 
   @override
-  Future<Either<OpenAIError, List<String>>> generateImage({
+  Future<FlowyResult<List<String>, OpenAIError>> generateImage({
     required String prompt,
     int n = 1,
   }) async {
@@ -266,12 +270,14 @@ class HttpOpenAIRepository implements OpenAIRepository {
             .expand((e) => e)
             .map((e) => e.toString())
             .toList();
-        return Right(urls);
+        return FlowyResult.success(urls);
       } else {
-        return Left(OpenAIError.fromJson(json.decode(response.body)['error']));
+        return FlowyResult.failure(
+          OpenAIError.fromJson(json.decode(response.body)['error']),
+        );
       }
     } catch (error) {
-      return Left(OpenAIError(message: error.toString()));
+      return FlowyResult.failure(OpenAIError(message: error.toString()));
     }
   }
 }

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/openai/widgets/auto_completion_node_widget.dart

@@ -193,7 +193,7 @@ class _AutoCompletionBlockComponentState
     await _updateEditingText();
 
     final userProfile = await UserBackendService.getCurrentUserProfile()
-        .then((value) => value.toOption().toNullable());
+        .then((value) => value.toNullable());
     if (userProfile == null) {
       await loading.stop();
       if (mounted) {
@@ -290,7 +290,7 @@ class _AutoCompletionBlockComponentState
     }
     // generate new response
     final userProfile = await UserBackendService.getCurrentUserProfile()
-        .then((value) => value.toOption().toNullable());
+        .then((value) => value.toNullable());
     if (userProfile == null) {
       await loading.stop();
       if (mounted) {

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/openai/widgets/smart_edit_toolbar_item.dart

@@ -41,8 +41,8 @@ class _SmartEditActionListState extends State<SmartEditActionList> {
     UserBackendService.getCurrentUserProfile().then((value) {
       setState(() {
         isOpenAIEnabled = value.fold(
-          (l) => false,
+          (s) => s.openaiKey.isNotEmpty,
-          (r) => r.openaiKey.isNotEmpty,
+          (_) => false,
         );
       });
     });

frontend/appflowy_flutter/lib/plugins/document/presentation/editor_plugins/stability_ai/stability_ai_client.dart

@@ -2,7 +2,7 @@ import 'dart:async';
 import 'dart:convert';
 
 import 'package:appflowy/plugins/document/presentation/editor_plugins/stability_ai/stability_ai_error.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:http/http.dart' as http;
 
 enum StabilityAIRequestType {
@@ -25,7 +25,7 @@ abstract class StabilityAIRepository {
   /// [n] is the number of images to generate
   ///
   /// the return value is a list of base64 encoded images
-  Future<Either<StabilityAIRequestError, List<String>>> generateImage({
+  Future<FlowyResult<List<String>, StabilityAIRequestError>> generateImage({
     required String prompt,
     int n = 1,
   });
@@ -46,7 +46,7 @@ class HttpStabilityAIRepository implements StabilityAIRepository {
       };
 
   @override
-  Future<Either<StabilityAIRequestError, List<String>>> generateImage({
+  Future<FlowyResult<List<String>, StabilityAIRequestError>> generateImage({
     required String prompt,
     int n = 1,
   }) async {
@@ -76,16 +76,16 @@ class HttpStabilityAIRepository implements StabilityAIRepository {
               (e) => e['base64'].toString(),
             )
             .toList();
-        return Right(base64Images);
+        return FlowyResult.success(base64Images);
       } else {
-        return Left(
+        return FlowyResult.failure(
           StabilityAIRequestError(
             data['message'].toString(),
           ),
         );
       }
     } catch (error) {
-      return Left(
+      return FlowyResult.failure(
         StabilityAIRequestError(
           error.toString(),
         ),

frontend/appflowy_flutter/lib/plugins/inline_actions/handlers/date_reference.dart

@@ -92,8 +92,8 @@ class DateReferenceService {
     final result = await DateService.queryDate(search);
 
     result.fold(
-      (l) {},
       (date) => options.insert(0, _itemFromDate(date)),
+      (_) {},
     );
   }
 

frontend/appflowy_flutter/lib/plugins/inline_actions/handlers/reminder_reference.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/material.dart';
-
 import 'package:appflowy/date/date_service.dart';
 import 'package:appflowy/generated/locale_keys.g.dart';
 import 'package:appflowy/plugins/document/application/doc_bloc.dart';
@@ -13,6 +11,7 @@ import 'package:appflowy_backend/protobuf/flowy-user/reminder.pb.dart';
 import 'package:appflowy_editor/appflowy_editor.dart';
 import 'package:easy_localization/easy_localization.dart';
 import 'package:fixnum/fixnum.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:nanoid/nanoid.dart';
 
@@ -111,13 +110,13 @@ class ReminderReferenceService {
     final result = await DateService.queryDate(search);
 
     result.fold(
-      (l) {},
       (date) {
         // Only insert dates in the future
         if (DateTime.now().isBefore(date)) {
           options.insert(0, _itemFromDate(date));
         }
       },
+      (_) {},
     );
   }
 

frontend/appflowy_flutter/lib/plugins/trash/application/trash_bloc.dart

@@ -3,7 +3,7 @@ import 'package:appflowy/plugins/trash/application/trash_service.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/trash.pb.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:freezed_annotation/freezed_annotation.dart';
 
@@ -26,13 +26,15 @@ class TrashBloc extends Bloc<TrashEvent, TrashState> {
         initial: (e) async {
           _listener.start(trashUpdated: _listenTrashUpdated);
           final result = await _service.readTrash();
+
           emit(
             result.fold(
               (object) => state.copyWith(
                 objects: object.items,
-                successOrFailure: left(unit),
+                successOrFailure: FlowyResult.success(null),
               ),
-              (error) => state.copyWith(successOrFailure: right(error)),
+              (error) =>
+                  state.copyWith(successOrFailure: FlowyResult.failure(error)),
             ),
           );
         },
@@ -60,18 +62,20 @@ class TrashBloc extends Bloc<TrashEvent, TrashState> {
   }
 
   Future<void> _handleResult(
-    Either<dynamic, FlowyError> result,
+    FlowyResult<dynamic, FlowyError> result,
     Emitter<TrashState> emit,
   ) async {
     emit(
       result.fold(
-        (l) => state.copyWith(successOrFailure: left(unit)),
+        (l) => state.copyWith(successOrFailure: FlowyResult.success(null)),
-        (error) => state.copyWith(successOrFailure: right(error)),
+        (error) => state.copyWith(successOrFailure: FlowyResult.failure(error)),
       ),
     );
   }
 
-  void _listenTrashUpdated(Either<List<TrashPB>, FlowyError> trashOrFailed) {
+  void _listenTrashUpdated(
+    FlowyResult<List<TrashPB>, FlowyError> trashOrFailed,
+  ) {
     trashOrFailed.fold(
       (trash) {
         add(TrashEvent.didReceiveTrash(trash));
@@ -103,11 +107,11 @@ class TrashEvent with _$TrashEvent {
 class TrashState with _$TrashState {
   const factory TrashState({
     required List<TrashPB> objects,
-    required Either<Unit, FlowyError> successOrFailure,
+    required FlowyResult<void, FlowyError> successOrFailure,
   }) = _TrashState;
 
   factory TrashState.init() => TrashState(
         objects: [],
-        successOrFailure: left(unit),
+        successOrFailure: FlowyResult.success(null),
       );
 }

frontend/appflowy_flutter/lib/plugins/trash/application/trash_listener.dart

@@ -1,15 +1,16 @@
 import 'dart:async';
 import 'dart:typed_data';
+
 import 'package:appflowy/core/notification/folder_notification.dart';
-import 'package:dartz/dartz.dart';
-import 'package:appflowy_backend/protobuf/flowy-notification/subject.pb.dart';
-import 'package:appflowy_backend/protobuf/flowy-folder/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-folder/notification.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/trash.pb.dart';
+import 'package:appflowy_backend/protobuf/flowy-notification/subject.pb.dart';
 import 'package:appflowy_backend/rust_stream.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 typedef TrashUpdatedCallback = void Function(
-  Either<List<TrashPB>, FlowyError> trashOrFailed,
+  FlowyResult<List<TrashPB>, FlowyError> trashOrFailed,
 );
 
 class TrashListener {
@@ -29,7 +30,7 @@ class TrashListener {
 
   void _observableCallback(
     FolderNotification ty,
-    Either<Uint8List, FlowyError> result,
+    FlowyResult<Uint8List, FlowyError> result,
   ) {
     switch (ty) {
       case FolderNotification.DidUpdateTrash:
@@ -37,9 +38,9 @@ class TrashListener {
           result.fold(
             (payload) {
               final repeatedTrash = RepeatedTrashPB.fromBuffer(payload);
-              _trashUpdated!(left(repeatedTrash.items));
+              _trashUpdated!(FlowyResult.success(repeatedTrash.items));
             },
-            (error) => _trashUpdated!(right(error)),
+            (error) => _trashUpdated!(FlowyResult.failure(error)),
           );
         }
         break;

frontend/appflowy_flutter/lib/plugins/trash/application/trash_service.dart

@@ -1,21 +1,22 @@
 import 'dart:async';
-import 'package:dartz/dartz.dart';
+
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/trash.pb.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 
 class TrashService {
-  Future<Either<RepeatedTrashPB, FlowyError>> readTrash() {
+  Future<FlowyResult<RepeatedTrashPB, FlowyError>> readTrash() {
     return FolderEventListTrashItems().send();
   }
 
-  Future<Either<Unit, FlowyError>> putback(String trashId) {
+  Future<FlowyResult<void, FlowyError>> putback(String trashId) {
     final id = TrashIdPB.create()..id = trashId;
 
     return FolderEventRestoreTrashItem(id).send();
   }
 
-  Future<Either<Unit, FlowyError>> deleteViews(List<String> trash) {
+  Future<FlowyResult<void, FlowyError>> deleteViews(List<String> trash) {
     final items = trash.map((trash) {
       return TrashIdPB.create()..id = trash;
     });
@@ -24,11 +25,11 @@ class TrashService {
     return FolderEventPermanentlyDeleteTrashItem(ids).send();
   }
 
-  Future<Either<Unit, FlowyError>> restoreAll() {
+  Future<FlowyResult<void, FlowyError>> restoreAll() {
     return FolderEventRecoverAllTrashItems().send();
   }
 
-  Future<Either<Unit, FlowyError>> deleteAll() {
+  Future<FlowyResult<void, FlowyError>> deleteAll() {
     return FolderEventPermanentlyDeleteAllTrashItem().send();
   }
 }

frontend/appflowy_flutter/lib/plugins/util.dart

@@ -1,18 +1,17 @@
 import 'package:appflowy/startup/plugin/plugin.dart';
 import 'package:appflowy/workspace/application/view/view_listener.dart';
-import 'package:dartz/dartz.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-folder/view.pb.dart';
 import 'package:flutter/material.dart';
 
-class ViewPluginNotifier extends PluginNotifier<Option<DeletedViewPB>> {
+class ViewPluginNotifier extends PluginNotifier<DeletedViewPB?> {
   ViewPluginNotifier({
     required this.view,
   }) : _viewListener = ViewListener(viewId: view.id) {
     _viewListener?.start(
       onViewUpdated: (updatedView) => view = updatedView,
       onViewMoveToTrash: (result) => result.fold(
-        (deletedView) => isDeleted.value = some(deletedView),
+        (deletedView) => isDeleted.value = deletedView,
         (err) => Log.error(err),
       ),
     );
@@ -22,7 +21,7 @@ class ViewPluginNotifier extends PluginNotifier<Option<DeletedViewPB>> {
   final ViewListener? _viewListener;
 
   @override
-  final ValueNotifier<Option<DeletedViewPB>> isDeleted = ValueNotifier(none());
+  final ValueNotifier<DeletedViewPB?> isDeleted = ValueNotifier(null);
 
   @override
   void dispose() {

frontend/appflowy_flutter/lib/startup/deps_resolver.dart

@@ -90,15 +90,15 @@ void _resolveCommonService(
     () async {
       final result = await UserBackendService.getCurrentUserProfile();
       return result.fold(
-        (l) {
+        (s) {
-          throw Exception('Failed to get user profile: ${l.msg}');
-        },
-        (r) {
           return HttpOpenAIRepository(
             client: http.Client(),
-            apiKey: r.openaiKey,
+            apiKey: s.openaiKey,
           );
         },
+        (e) {
+          throw Exception('Failed to get user profile: ${e.msg}');
+        },
       );
     },
   );
@@ -107,15 +107,15 @@ void _resolveCommonService(
     () async {
       final result = await UserBackendService.getCurrentUserProfile();
       return result.fold(
-        (l) {
+        (s) {
-          throw Exception('Failed to get user profile: ${l.msg}');
-        },
-        (r) {
           return HttpStabilityAIRepository(
             client: http.Client(),
-            apiKey: r.stabilityAiKey,
+            apiKey: s.stabilityAiKey,
           );
         },
+        (e) {
+          throw Exception('Failed to get user profile: ${e.msg}');
+        },
       );
     },
   );

frontend/appflowy_flutter/lib/startup/tasks/app_window_size_manager.dart

@@ -32,7 +32,7 @@ class WindowSizeManager {
     final defaultWindowSize = jsonEncode({height: 600.0, width: 800.0});
     final windowSize = await getIt<KeyValueStorage>().get(KVKeys.windowSize);
     final size = json.decode(
-      windowSize.getOrElse(() => defaultWindowSize),
+      windowSize ?? defaultWindowSize,
     );
     return Size(size[width]!, size[height]!);
   }
@@ -49,12 +49,10 @@ class WindowSizeManager {
 
   Future<Offset?> getPosition() async {
     final position = await getIt<KeyValueStorage>().get(KVKeys.windowPosition);
-    return position.fold(
+    if (position == null) {
-      () => null,
+      return null;
-      (r) {
+    }
-        final offset = json.decode(r);
+    final offset = json.decode(position);
     return Offset(offset[dx], offset[dy]);
-      },
-    );
   }
 }

frontend/appflowy_flutter/lib/startup/tasks/appflowy_cloud_task.dart

@@ -16,7 +16,7 @@ import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/code.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-user/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flutter/material.dart';
 import 'package:url_protocol/url_protocol.dart';
 
@@ -29,7 +29,7 @@ class AppFlowyCloudDeepLink {
           await _handleUri(uri);
         },
         onError: (Object err, StackTrace stackTrace) {
-          Log.error('on deeplink stream error: ${err.toString()}', stackTrace);
+          Log.error('on DeepLink stream error: ${err.toString()}', stackTrace);
           _deeplinkSubscription?.cancel();
           _deeplinkSubscription = null;
         },
@@ -46,7 +46,7 @@ class AppFlowyCloudDeepLink {
   final _appLinks = AppLinks();
 
   ValueNotifier<DeepLinkResult?>? _stateNotifier = ValueNotifier(null);
-  Completer<Either<FlowyError, UserProfilePB>>? _completer;
+  Completer<FlowyResult<UserProfilePB, FlowyError>>? _completer;
 
   // The AppLinks is a singleton, so we need to cancel the previous subscription
   // before creating a new one.
@@ -58,8 +58,8 @@ class AppFlowyCloudDeepLink {
     _stateNotifier = null;
   }
 
-  void resigerCompleter(
+  void registerCompleter(
-    Completer<Either<FlowyError, UserProfilePB>> completer,
+    Completer<FlowyResult<UserProfilePB, FlowyError>> completer,
   ) {
     _completer = completer;
   }
@@ -86,11 +86,11 @@ class AppFlowyCloudDeepLink {
     _stateNotifier?.value = DeepLinkResult(state: DeepLinkState.none);
 
     if (uri == null) {
-      Log.error('onDeepLinkError: Unexpect empty deep link callback');
+      Log.error('onDeepLinkError: Unexpected empty deep link callback');
-      _completer?.complete(left(AuthError.emptyDeeplink));
+      _completer?.complete(FlowyResult.failure(AuthError.emptyDeepLink));
       _completer = null;
     }
-    return _isAuthCallbackDeeplink(uri!).fold(
+    return _isAuthCallbackDeepLink(uri!).fold(
       (_) async {
         final deviceId = await getDeviceId();
         final payload = OauthSignInPB(
@@ -101,9 +101,8 @@ class AppFlowyCloudDeepLink {
           },
         );
         _stateNotifier?.value = DeepLinkResult(state: DeepLinkState.loading);
-        final result = await UserEventOauthSignIn(payload)
+        final result =
-            .send()
+            await UserEventOauthSignIn(payload).send().then((value) => value);
-            .then((value) => value.swap());
 
         _stateNotifier?.value = DeepLinkResult(
           state: DeepLinkState.finish,
@@ -112,6 +111,9 @@ class AppFlowyCloudDeepLink {
         // If there is no completer, runAppFlowy() will be called.
         if (_completer == null) {
           await result.fold(
+            (_) async {
+              await runAppFlowy();
+            },
             (err) {
               Log.error(err);
               final context = AppGlobals.rootNavKey.currentState?.context;
@@ -122,9 +124,6 @@ class AppFlowyCloudDeepLink {
                 );
               }
             },
-            (_) async {
-              await runAppFlowy();
-            },
           );
         } else {
           _completer?.complete(result);
@@ -132,7 +131,7 @@ class AppFlowyCloudDeepLink {
         }
       },
       (err) {
-        Log.error('onDeepLinkError: Unexpect deep link: $err');
+        Log.error('onDeepLinkError: Unexpected deep link: $err');
         if (_completer == null) {
           final context = AppGlobals.rootNavKey.currentState?.context;
           if (context != null) {
@@ -142,19 +141,19 @@ class AppFlowyCloudDeepLink {
             );
           }
         } else {
-          _completer?.complete(left(err));
+          _completer?.complete(FlowyResult.failure(err));
           _completer = null;
         }
       },
     );
   }
 
-  Either<(), FlowyError> _isAuthCallbackDeeplink(Uri uri) {
+  FlowyResult<void, FlowyError> _isAuthCallbackDeepLink(Uri uri) {
     if (uri.fragment.contains('access_token')) {
-      return left(());
+      return FlowyResult.success(null);
     }
 
-    return right(
+    return FlowyResult.failure(
       FlowyError.create()
         ..code = ErrorCode.MissingAuthField
         ..msg = uri.path,
@@ -197,7 +196,7 @@ class DeepLinkResult {
   DeepLinkResult({required this.state, this.result});
 
   final DeepLinkState state;
-  final Either<FlowyError, UserProfilePB>? result;
+  final FlowyResult<UserProfilePB, FlowyError>? result;
 }
 
 enum DeepLinkState {

frontend/appflowy_flutter/lib/startup/tasks/generate_router.dart

@@ -580,8 +580,8 @@ GoRoute _rootRoute(Widget child) {
       // Every time before navigating to splash screen, we check if user is already logged in in desktop. It is used to skip showing splash screen when user just changes apperance settings like theme mode.
       final userResponse = await getIt<AuthService>().getUser();
       final routeName = userResponse.fold(
-        (error) => null,
         (user) => DesktopHomeScreen.routeName,
+        (error) => null,
       );
       if (routeName != null && !PlatformExtension.isMobile) return routeName;
 

frontend/appflowy_flutter/lib/user/application/auth/af_cloud_auth_service.dart

@@ -2,13 +2,13 @@ import 'dart:async';
 
 import 'package:appflowy/startup/startup.dart';
 import 'package:appflowy/startup/tasks/appflowy_cloud_task.dart';
-import 'package:appflowy/user/application/auth/backend_auth_service.dart';
 import 'package:appflowy/user/application/auth/auth_service.dart';
+import 'package:appflowy/user/application/auth/backend_auth_service.dart';
 import 'package:appflowy/user/application/user_service.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-user/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:url_launcher/url_launcher.dart';
 
 import 'auth_error.dart';
@@ -21,7 +21,7 @@ class AppFlowyCloudAuthService implements AuthService {
   );
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signUp({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signUp({
     required String name,
     required String email,
     required String password,
@@ -31,7 +31,7 @@ class AppFlowyCloudAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signInWithEmailPassword({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signInWithEmailPassword({
     required String email,
     required String password,
     Map<String, String> params = const {},
@@ -40,7 +40,7 @@ class AppFlowyCloudAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signUpWithOAuth({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signUpWithOAuth({
     required String platform,
     Map<String, String> params = const {},
   }) async {
@@ -61,22 +61,23 @@ class AppFlowyCloudAuthService implements AuthService {
           webOnlyWindowName: '_self',
         );
 
-        final completer = Completer<Either<FlowyError, UserProfilePB>>();
+        final completer = Completer<FlowyResult<UserProfilePB, FlowyError>>();
         if (isSuccess) {
           // The [AppFlowyCloudDeepLink] must be registered before using the
           // [AppFlowyCloudAuthService].
           if (getIt.isRegistered<AppFlowyCloudDeepLink>()) {
-            getIt<AppFlowyCloudDeepLink>().resigerCompleter(completer);
+            getIt<AppFlowyCloudDeepLink>().registerCompleter(completer);
           } else {
             throw Exception('AppFlowyCloudDeepLink is not registered');
           }
         } else {
-          completer.complete(left(AuthError.signInWithOauthError));
+          completer
+              .complete(FlowyResult.failure(AuthError.signInWithOauthError));
         }
 
         return completer.future;
       },
-      (r) => left(r),
+      (r) => FlowyResult.failure(r),
     );
   }
 
@@ -86,14 +87,14 @@ class AppFlowyCloudAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signUpAsGuest({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signUpAsGuest({
     Map<String, String> params = const {},
   }) async {
     return _backendAuthService.signUpAsGuest();
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signInWithMagicLink({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signInWithMagicLink({
     required String email,
     Map<String, String> params = const {},
   }) async {
@@ -101,7 +102,7 @@ class AppFlowyCloudAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> getUser() async {
+  Future<FlowyResult<UserProfilePB, FlowyError>> getUser() async {
     return UserBackendService.getCurrentUserProfile();
   }
 }

frontend/appflowy_flutter/lib/user/application/auth/af_cloud_mock_auth_service.dart

@@ -1,14 +1,14 @@
 import 'dart:async';
 
-import 'package:appflowy/user/application/auth/backend_auth_service.dart';
 import 'package:appflowy/user/application/auth/auth_service.dart';
+import 'package:appflowy/user/application/auth/backend_auth_service.dart';
 import 'package:appflowy/user/application/auth/device_id.dart';
 import 'package:appflowy/user/application/user_service.dart';
 import 'package:appflowy_backend/dispatch/dispatch.dart';
 import 'package:appflowy_backend/log.dart';
 import 'package:appflowy_backend/protobuf/flowy-error/errors.pb.dart';
 import 'package:appflowy_backend/protobuf/flowy-user/protobuf.dart';
-import 'package:dartz/dartz.dart';
+import 'package:appflowy_result/appflowy_result.dart';
 import 'package:flowy_infra/uuid.dart';
 
 /// Only used for testing.
@@ -22,7 +22,7 @@ class AppFlowyCloudMockAuthService implements AuthService {
       BackendAuthService(AuthenticatorPB.Supabase);
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signUp({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signUp({
     required String name,
     required String email,
     required String password,
@@ -32,7 +32,7 @@ class AppFlowyCloudMockAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signInWithEmailPassword({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signInWithEmailPassword({
     required String email,
     required String password,
     Map<String, String> params = const {},
@@ -41,7 +41,7 @@ class AppFlowyCloudMockAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signUpWithOAuth({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signUpWithOAuth({
     required String platform,
     Map<String, String> params = const {},
   }) async {
@@ -65,12 +65,12 @@ class AppFlowyCloudMockAuthService implements AuthService {
         Log.info("UserEventOauthSignIn with payload: $payload");
         return UserEventOauthSignIn(payload).send().then((value) {
           value.fold((l) => null, (err) => Log.error(err));
-          return value.swap();
+          return value;
         });
       },
       (r) {
         Log.error(r);
-        return left(r);
+        return FlowyResult.failure(r);
       },
     );
   }
@@ -81,14 +81,14 @@ class AppFlowyCloudMockAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signUpAsGuest({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signUpAsGuest({
     Map<String, String> params = const {},
   }) async {
     return _appFlowyAuthService.signUpAsGuest();
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> signInWithMagicLink({
+  Future<FlowyResult<UserProfilePB, FlowyError>> signInWithMagicLink({
     required String email,
     Map<String, String> params = const {},
   }) async {
@@ -96,7 +96,7 @@ class AppFlowyCloudMockAuthService implements AuthService {
   }
 
   @override
-  Future<Either<FlowyError, UserProfilePB>> getUser() async {
+  Future<FlowyResult<UserProfilePB, FlowyError>> getUser() async {
     return UserBackendService.getCurrentUserProfile();
   }
 }