Imlement simple history manager in core package

packages/collaboration-manager/src/BatchedOperation.spec.ts

@@ -167,5 +167,39 @@ describe('BatchedOperation', () => {
 
       expect(batch.canAdd(op2)).toBe(false);
     });
+
+    it('should return true for consecutive backspace Delete operations', () => {
+      // Backspace: position decrements each time – [3,3], [2,2]
+      /* eslint-disable @typescript-eslint/no-magic-numbers */
+      const op1 = new Operation(OperationType.Delete, createIndexByRange([3, 3]), { payload: 'b' }, userId);
+      const op2 = new Operation(OperationType.Delete, createIndexByRange([2, 2]), { payload: 'a' }, userId);
+      /* eslint-enable @typescript-eslint/no-magic-numbers */
+
+      const batch = new BatchedOperation(op1);
+
+      expect(batch.canAdd(op2)).toBe(true);
+    });
+
+    it('should return true for consecutive forward Delete operations', () => {
+      // Forward delete: position stays the same after each deletion – [0,0], [0,0]
+      const op1 = new Operation(OperationType.Delete, templateIndex, { payload: 'a' }, userId);
+      const op2 = new Operation(OperationType.Delete, templateIndex, { payload: 'b' }, userId);
+
+      const batch = new BatchedOperation(op1);
+
+      expect(batch.canAdd(op2)).toBe(true);
+    });
+
+    it('should return false for non-consecutive Delete operations', () => {
+      // Gap of 2 – should not be batched
+      /* eslint-disable @typescript-eslint/no-magic-numbers */
+      const op1 = new Operation(OperationType.Delete, createIndexByRange([3, 3]), { payload: 'c' }, userId);
+      const op2 = new Operation(OperationType.Delete, createIndexByRange([1, 1]), { payload: 'a' }, userId);
+      /* eslint-enable @typescript-eslint/no-magic-numbers */
+
+      const batch = new BatchedOperation(op1);
+
+      expect(batch.canAdd(op2)).toBe(false);
+    });
   });
 });

packages/collaboration-manager/src/BatchedOperation.ts

@@ -142,6 +142,20 @@ export class BatchedOperation<T extends OperationType = OperationType> extends O
       return false;
     }
 
-    return op.index.textRange![0] === lastOp.index.textRange![1] + 1;
+    if (op.type === OperationType.Insert) {
+      /**
+       * For Insert operations, each character is appended sequentially:
+       * [0,0], [1,1], [2,2] ...
+       */
+      return op.index.textRange![0] === lastOp.index.textRange![1] + 1;
+    }
+
+    /**
+     * For Delete operations two consecutive patterns are allowed:
+     * - Backspace: each deletion decrements the position: [3,3], [2,2], [1,1] ...
+     * - Forward delete: the position stays the same after each deletion: [0,0], [0,0] ...
+     */
+    return op.index.textRange![0] === lastOp.index.textRange![0] - 1
+      || op.index.textRange![0] === lastOp.index.textRange![0];
   }
 }

packages/collaboration-manager/src/CollaborationManager.ts

@@ -6,11 +6,15 @@
   TextFormattedEvent, TextRemovedEvent,
   TextUnformattedEvent
 } from '@editorjs/model';
+import type {
+  UndoCoreEvent,
+  EditorAPI,
+  EditorjsPlugin,
+  EditorjsPluginParams,
+  RedoCoreEvent
+} from '@editorjs/sdk';
 import {
   CoreEventType,
-  type EditorAPI,
-  type EditorjsPlugin,
-  type EditorjsPluginParams,
   PluginType
 } from '@editorjs/sdk';
 import { OTClient } from './client/index.js';
@@ -97,10 +101,14 @@
     this.#config = config;
     this.#undoRedoManager = new UndoRedoManager();
 
-    const onUndo = (): void => {
+    const onUndo = (e: UndoCoreEvent): void => {
+      e.preventDefault();
+
       this.undo();
     };
-    const onRedo = (): void => {
+    const onRedo = (e: RedoCoreEvent): void => {
+      e.preventDefault();
+
       this.redo();
     };
     const onReady = (): void => {

packages/collaboration-manager/test/mocks/createManager.ts

@@ -2,7 +2,7 @@ import type { EditorDocumentSerialized, ModelEvents } from '@editorjs/model';
 import { EventType } from '@editorjs/model';
 import type { EditorJSModel } from '@editorjs/model';
 import { EventBus } from '@editorjs/sdk';
-import type { CoreConfigValidated, DocumentAPI, EditorAPI, InsertRemoveDataParams, ModifyDataParams } from '@editorjs/sdk';
+import type { CoreConfigValidated, DocumentAPI, EditorAPI, InsertRemoveDataParams, ModifyDataParams, BlocksAPI } from '@editorjs/sdk';
 import { CollaborationManager } from '../../src/CollaborationManager.js';
 
 /**
@@ -28,7 +28,7 @@ function createMockDocumentAPI(model: EditorJSModel): DocumentAPI {
     modifyData({ userId, index, data }: ModifyDataParams): void {
       model.modifyData(userId, index, data);
     },
-  };
+  } as DocumentAPI;
 }
 
 /**
@@ -37,16 +37,17 @@ function createMockDocumentAPI(model: EditorJSModel): DocumentAPI {
  * @param model - the EditorJS model instance
  * @returns an object containing the manager and the eventBus used
  */
-export function createManager(config: CoreConfigValidated, model: EditorJSModel): { manager: CollaborationManager;
-  eventBus: EventBus; } {
+export function createManager(config: CoreConfigValidated, model: EditorJSModel): {
+  manager: CollaborationManager;
+  eventBus: EventBus;
+} {
   const eventBus = new EventBus();
 
   const api: EditorAPI = {
     document: createMockDocumentAPI(model),
-    // eslint-disable-next-line @typescript-eslint/no-explicit-any
     blocks: {
       render: () => undefined,
-    } as any,
+    } as unknown as BlocksAPI,
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     selection: {} as any,
     // eslint-disable-next-line @typescript-eslint/no-explicit-any

packages/core/src/api/DocumentAPI/DocumentAPI.spec.ts

@@ -1,6 +1,16 @@
 /* eslint-disable @typescript-eslint/naming-convention */
 import { beforeEach, describe, expect, jest } from '@jest/globals';
-import type { CoreConfigValidated } from '@editorjs/sdk';
+import type { CoreConfigValidated, EventBus } from '@editorjs/sdk';
+
+jest.unstable_mockModule('@editorjs/sdk', () => ({
+  UndoCoreEvent: class UndoCoreEvent {
+    public name = 'undo';
+  },
+  RedoCoreEvent: class RedoCoreEvent {
+    public name = 'redo';
+  },
+  EventBus: jest.fn(),
+}));
 
 jest.unstable_mockModule('@editorjs/model', () => {
   const EditorJSModel = jest.fn(() => ({
@@ -22,7 +32,13 @@ describe('DocumentAPI', () => {
   // @ts-expect-error - mock object, don't need to pass any arguments
   const model = new EditorJSModel();
 
-  const documentAPI = new DocumentAPI(model, {} as unknown as CoreConfigValidated);
+  const dispatchEvent = jest.fn();
+
+  const documentAPI = new DocumentAPI(
+    model,
+    {} as unknown as CoreConfigValidated,
+    { dispatchEvent } as unknown as EventBus
+  );
 
   beforeEach(() => {
     jest.resetAllMocks();
@@ -52,4 +68,20 @@ describe('DocumentAPI', () => {
       expect(data).toEqual(mockedSerializedModel);
     });
   });
+
+  describe('.undo()', () => {
+    it('should dispatch an undo core event', () => {
+      documentAPI.undo();
+
+      expect(dispatchEvent).toBeCalledWith(expect.objectContaining({ name: 'undo' }));
+    });
+  });
+
+  describe('.redo()', () => {
+    it('should dispatch an redo core event', () => {
+      documentAPI.redo();
+
+      expect(dispatchEvent).toBeCalledWith(expect.objectContaining({ name: 'redo' }));
+    });
+  });
 });

packages/core/src/api/DocumentAPI/DocumentAPI.ts

@@ -3,9 +3,9 @@ import 'reflect-metadata';
 import { type EditorDocumentSerialized, EditorJSModel, EventType, type ModelEvents } from '@editorjs/model';
 import {
   CoreConfigValidated,
-  DocumentAPI as DocumentApiInterface,
+  DocumentAPI as DocumentApiInterface, EventBus,
   type InsertRemoveDataParams,
-  type ModifyDataParams
+  type ModifyDataParams, RedoCoreEvent, UndoCoreEvent
 } from '@editorjs/sdk';
 import { inject, injectable } from 'inversify';
 import { TOKENS } from '../../tokens.js';
@@ -26,18 +26,26 @@ export class DocumentAPI implements DocumentApiInterface {
    */
   #config: CoreConfigValidated;
 
+  /**
+   * Editor's event bus instance
+   */
+  #eventBus: EventBus;
+
   /**
    * DocumentAPI constructor
    * All parameters are injected through the IoC container
    * @param model - Editor's Document Model instance
    * @param config - Editor's config
+   * @param eventBus - Editor's event bus instance
    */
   constructor(
     model: EditorJSModel,
-    @inject(TOKENS.EditorConfig) config: CoreConfigValidated
+    @inject(TOKENS.EditorConfig) config: CoreConfigValidated,
+    eventBus: EventBus
   ) {
     this.#model = model;
     this.#config = config;
+    this.#eventBus = eventBus;
   }
 
   /**
@@ -91,4 +99,26 @@ export class DocumentAPI implements DocumentApiInterface {
   public modifyData({ userId = this.#config.userId, index, data }: ModifyDataParams): void {
     this.#model.modifyData(userId, index, data);
   }
+
+  /**
+   * Undoes the last change in the document
+   */
+  public undo(): void {
+    /**
+     * To enable Plugins to cancel the default undo/redo behavior,
+     * we have to dispatch event here instead of a direct call
+     */
+    this.#eventBus.dispatchEvent(new UndoCoreEvent());
+  }
+
+  /**
+   * Redoes the last undone change in the document
+   */
+  public redo(): void {
+    /**
+     * To enable Plugins to cancel the default undo/redo behavior,
+     * we have to dispatch event here instead of a direct call
+     */
+    this.#eventBus.dispatchEvent(new RedoCoreEvent());
+  }
 }