fix issue #2523 (#2639)

* fix isMutationBelongsToElement function: make it return true if the whole text node is deleted inside of some descendant of the passed element

* isMutationBelongsToElement function shouldn't return true if some of the ancestors of the passed element were added or deleted, only if the element itself

* add test case verifying that 'onChange' is fired when the whole text inside some nested  descendant of the block is removed

* replace introduced dependency with ToolMock

* add comment explaining isMutationBelongsToElement behaviour in case of adding/removing the passed element itself

* fix formatting

* added some more explanation

* added record to the changelog

---------

Co-authored-by: Peter Savchenko <specc.dev@gmail.com>

Author: VikhorKonstantin

docs/CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+### 2.30.0
+
+- `Fix` — `onChange` will be called when removing the entire text within a descendant element of a block.
+
 ### 2.29.1
 
 - `Fix` — Toolbox wont be shown when Slash pressed with along with Shift or Alt

src/components/utils/mutations.ts

@@ -8,28 +8,28 @@ export function isMutationBelongsToElement(mutationRecord: MutationRecord, eleme
   const { type, target, addedNodes, removedNodes } = mutationRecord;
 
   /**
-   * In case of removing the whole text in element, mutation type will be 'childList',
-   * 'removedNodes' will contain text node that is not existed anymore, so we can't check it with 'contains' method
-   * But Target will be the element itself, so we can detect it.
+   * Covers all types of mutations happened to the element or it's descendants with the only one exception - removing/adding the element itself;
    */
-  if (target === element) {
+  if (element.contains(target)) {
     return true;
   }
 
   /**
-   * Check typing and attributes changes
+   * In case of removing/adding the element itself, mutation type will be 'childList' and 'removedNodes'/'addedNodes' will contain the element.
    */
-  if (['characterData', 'attributes'].includes(type)) {
-    const targetElement = target.nodeType === Node.TEXT_NODE ? target.parentNode : target;
+  if (type === 'childList') {
+    const elementAddedItself = Array.from(addedNodes).some(node => node === element);
 
-    return element.contains(targetElement);
-  }
+    if (elementAddedItself) {
+      return true;
+    }
 
-  /**
-   * Check new/removed nodes
-   */
-  const addedNodesBelongsToBlock = Array.from(addedNodes).some(node => element.contains(node));
-  const removedNodesBelongsToBlock = Array.from(removedNodes).some(node => element.contains(node));
+    const elementRemovedItself = Array.from(removedNodes).some(node => node === element);
+
+    if (elementRemovedItself) {
+      return true;
+    }
+  }
 
-  return addedNodesBelongsToBlock || removedNodesBelongsToBlock;
+  return false;
 }

test/cypress/tests/onchange.cy.ts

@@ -1,5 +1,6 @@
 import Header from '@editorjs/header';
 import Code from '@editorjs/code';
+import ToolMock from '../fixtures/tools/ToolMock';
 import Delimiter from '@editorjs/delimiter';
 import { BlockAddedMutationType } from '../../../types/events/block/BlockAdded';
 import { BlockChangedMutationType } from '../../../types/events/block/BlockChanged';
@@ -787,4 +788,61 @@ describe('onChange callback', () => {
         }));
       });
   });
+
+  it('should be fired when the whole text inside some descendant of the block is removed', () => {
+    /**
+     * Mock of Tool with nested contenteditable element
+     */
+    class ToolWithContentEditableDescendant extends ToolMock {
+      /**
+       * Creates element with nested contenteditable element
+       */
+      public render(): HTMLElement {
+        const contenteditable = document.createElement('div');
+
+        contenteditable.contentEditable = 'true';
+        contenteditable.innerText = 'a';
+        contenteditable.setAttribute('data-cy', 'nested-contenteditable');
+
+        const wrapper = document.createElement('div');
+
+        wrapper.appendChild(contenteditable);
+
+        return wrapper;
+      }
+    }
+
+    const config = {
+      tools: {
+        testTool: {
+          class: ToolWithContentEditableDescendant,
+        },
+      },
+      data: {
+        blocks: [
+          {
+            type: 'testTool',
+            data: 'a',
+          },
+        ],
+      },
+      onChange: (): void => {
+        console.log('something changed');
+      },
+    };
+
+    cy.spy(config, 'onChange').as('onChange');
+    cy.createEditor(config).as('editorInstance');
+
+    cy.get('[data-cy=nested-contenteditable]')
+      .click()
+      .clear();
+
+    cy.get('@onChange').should('be.calledWithMatch', EditorJSApiMock, Cypress.sinon.match({
+      type: BlockChangedMutationType,
+      detail: {
+        index: 0,
+      },
+    }));
+  });
 });