diff --git a/apps/electron/src/helper/db/base-db-adapter.ts b/apps/electron/src/helper/db/base-db-adapter.ts
index afb68adc25..7d90c8a0bb 100644
--- a/apps/electron/src/helper/db/base-db-adapter.ts
+++ b/apps/electron/src/helper/db/base-db-adapter.ts
@@ -44,10 +44,10 @@ export abstract class BaseSQLiteAdapter {
     try {
       if (!this.db) {
         logger.warn(`${this.path} is not connected`);
-        return;
+        return null;
       }
       const blob = await this.db.getBlob(key);
-      return blob?.data;
+      return blob?.data ?? null;
     } catch (error) {
       logger.error('getBlob', error);
       return null;
diff --git a/apps/electron/src/helper/db/workspace-db-adapter.ts b/apps/electron/src/helper/db/workspace-db-adapter.ts
index 8eda459c4d..7ec8edc4af 100644
--- a/apps/electron/src/helper/db/workspace-db-adapter.ts
+++ b/apps/electron/src/helper/db/workspace-db-adapter.ts
@@ -128,7 +128,7 @@ export class WorkspaceSQLiteDB extends BaseSQLiteAdapter {
     if (doc) {
       return encodeStateAsUpdate(doc);
     }
-    return null;
+    return false;
   };
 
   // non-blocking and use yDoc to validate the update
diff --git a/apps/electron/src/helper/exposed.ts b/apps/electron/src/helper/exposed.ts
index 19bd140e76..a6f6da3ec7 100644
--- a/apps/electron/src/helper/exposed.ts
+++ b/apps/electron/src/helper/exposed.ts
@@ -1,12 +1,24 @@
+import type {
+  DBHandlers,
+  DialogHandlers,
+  WorkspaceHandlers,
+} from '@toeverything/infra/type';
+
 import { dbEvents, dbHandlers } from './db';
 import { dialogHandlers } from './dialog';
 import { workspaceEvents, workspaceHandlers } from './workspace';
 
+type AllHandlers = {
+  db: DBHandlers;
+  workspace: WorkspaceHandlers;
+  dialog: DialogHandlers;
+};
+
 export const handlers = {
   db: dbHandlers,
   workspace: workspaceHandlers,
   dialog: dialogHandlers,
-};
+} satisfies AllHandlers;
 
 export const events = {
   db: dbEvents,
diff --git a/packages/infra/src/type.ts b/packages/infra/src/type.ts
index ad845cc3e0..cee56f6247 100644
--- a/packages/infra/src/type.ts
+++ b/packages/infra/src/type.ts
@@ -94,7 +94,7 @@ export type DBHandlers = {
   getDocAsUpdates: (
     workspaceId: string,
     subdocId?: string
-  ) => Promise<Uint8Array>;
+  ) => Promise<Uint8Array | false>;
   applyDocUpdate: (
     id: string,
     update: Uint8Array,
@@ -164,7 +164,7 @@ export type DialogHandlers = {
     dbFileLocation?: string
   ) => Promise<MoveDBFileResult>;
   selectDBFileLocation: () => Promise<SelectDBFileLocationResult>;
-  setFakeDialogResult: (result: any) => Promise<FakeDialogResult>;
+  setFakeDialogResult: (result: any) => Promise<void>;
 };
 
 export type UIHandlers = {