fix(renderer): handle empty array as data.blocks

docs/CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+### 2.29.0
+
+- `Fix` — Passing an empty array via initial data or `blocks.render()` won't break the editor
+
 ### 2.28.0
 
 - `New` - Block ids now displayed in DOM via a data-id attribute. Could be useful for plugins that want to access a Block's element by id.

src/components/blocks.ts

@@ -323,7 +323,7 @@ export default class Blocks {
    * @param {number} index — Block index
    * @returns {Block}
    */
-  public get(index: number): Block {
+  public get(index: number): Block | undefined {
     return this.blocks[index];
   }
 

src/components/modules/blockManager.ts

@@ -587,13 +587,28 @@ export default class BlockManager extends Module {
     return this.insert({ data });
   }
 
+  /**
+   * Returns Block by passed index
+   *
+   * If we pass -1 as index, the last block will be returned
+   * There shouldn't be a case when there is no blocks at all — at least one always should exist
+   */
+  public getBlockByIndex(index: -1): Block;
+
+  /**
+   * Returns Block by passed index.
+   *
+   * Could return undefined if there is no block with such index
+   */
+  public getBlockByIndex(index: number): Block | undefined;
+
   /**
    * Returns Block by passed index
    *
    * @param {number} index - index to get. -1 to get last
    * @returns {Block}
    */
-  public getBlockByIndex(index): Block {
+  public getBlockByIndex(index: number): Block | undefined {
     if (index === -1) {
       index = this._blocks.length - 1;
     }

src/components/modules/renderer.ts

@@ -18,53 +18,57 @@ export default class Renderer extends Module {
     return new Promise((resolve) => {
       const { Tools, BlockManager } = this.Editor;
 
-      /**
-       * Create Blocks instances
-       */
-      const blocks = blocksData.map(({ type: tool, data, tunes, id }) => {
-        if (Tools.available.has(tool) === false) {
-          _.logLabeled(`Tool «${tool}» is not found. Check 'tools' property at the Editor.js config.`, 'warn');
+      if (blocksData.length === 0) {
+        BlockManager.insert();
+      } else {
+        /**
+         * Create Blocks instances
+         */
+        const blocks = blocksData.map(({ type: tool, data, tunes, id }) => {
+          if (Tools.available.has(tool) === false) {
+            _.logLabeled(`Tool «${tool}» is not found. Check 'tools' property at the Editor.js config.`, 'warn');
 
-          data = this.composeStubDataForTool(tool, data, id);
-          tool = Tools.stubTool;
-        }
+            data = this.composeStubDataForTool(tool, data, id);
+            tool = Tools.stubTool;
+          }
 
-        let block: Block;
+          let block: Block;
 
-        try {
-          block = BlockManager.composeBlock({
-            id,
-            tool,
-            data,
-            tunes,
-          });
-        } catch (error) {
-          _.log(`Block «${tool}» skipped because of plugins error`, 'error', {
-            data,
-            error,
-          });
+          try {
+            block = BlockManager.composeBlock({
+              id,
+              tool,
+              data,
+              tunes,
+            });
+          } catch (error) {
+            _.log(`Block «${tool}» skipped because of plugins error`, 'error', {
+              data,
+              error,
+            });
 
-          /**
-           * If tool throws an error during render, we should render stub instead of it
-           */
-          data = this.composeStubDataForTool(tool, data, id);
-          tool = Tools.stubTool;
+            /**
+             * If tool throws an error during render, we should render stub instead of it
+             */
+            data = this.composeStubDataForTool(tool, data, id);
+            tool = Tools.stubTool;
 
-          block = BlockManager.composeBlock({
-            id,
-            tool,
-            data,
-            tunes,
-          });
-        }
+            block = BlockManager.composeBlock({
+              id,
+              tool,
+              data,
+              tunes,
+            });
+          }
 
-        return block;
-      });
+          return block;
+        });
 
-      /**
-       * Insert batch of Blocks
-       */
-      BlockManager.insertMany(blocks);
+        /**
+         * Insert batch of Blocks
+         */
+        BlockManager.insertMany(blocks);
+      }
 
       /**
        * Wait till browser will render inserted Blocks and resolve a promise

src/components/modules/ui.ts

@@ -694,17 +694,10 @@ export default class UI extends Module<UINodes> {
    *      - otherwise, add a new empty Block and set a Caret to that
    */
   private redactorClicked(event: MouseEvent): void {
-    const { BlockSelection } = this.Editor;
-
     if (!Selection.isCollapsed) {
       return;
     }
 
-    const stopPropagation = (): void => {
-      event.stopImmediatePropagation();
-      event.stopPropagation();
-    };
-
     /**
      * case when user clicks on anchor element
      * if it is clicked via ctrl key, then we open new window with url
@@ -713,7 +706,8 @@ export default class UI extends Module<UINodes> {
     const ctrlKey = event.metaKey || event.ctrlKey;
 
     if ($.isAnchor(element) && ctrlKey) {
-      stopPropagation();
+      event.stopImmediatePropagation();
+      event.stopPropagation();
 
       const href = element.getAttribute('href');
       const validUrl = _.getValidUrl(href);
@@ -723,10 +717,22 @@ export default class UI extends Module<UINodes> {
       return;
     }
 
+    this.processBottomZoneClick(event);
+  }
+
+  /**
+   * Check if user clicks on the Editor's bottom zone:
+   *  - set caret to the last block
+   *  - or add new empty block
+   *
+   * @param event - click event
+   */
+  private processBottomZoneClick(event: MouseEvent): void {
     const lastBlock = this.Editor.BlockManager.getBlockByIndex(-1);
+
     const lastBlockBottomCoord = $.offset(lastBlock.holder).bottom;
     const clickedCoord = event.pageY;
-
+    const { BlockSelection } = this.Editor;
     const isClickedBottom = event.target instanceof Element &&
       event.target.isEqualNode(this.nodes.redactor) &&
       /**
@@ -740,7 +746,8 @@ export default class UI extends Module<UINodes> {
       lastBlockBottomCoord < clickedCoord;
 
     if (isClickedBottom) {
-      stopPropagation();
+      event.stopImmediatePropagation();
+      event.stopPropagation();
 
       const { BlockManager, Caret, Toolbar } = this.Editor;
 

test/cypress/tests/modules/Renderer.cy.ts

@@ -1,4 +1,5 @@
 import ToolMock from '../../fixtures/tools/ToolMock';
+import type EditorJS from '../../../../types/index';
 
 describe('Renderer module', function () {
   it('should not cause onChange firing during initial rendering', function () {
@@ -146,4 +147,33 @@ describe('Renderer module', function () {
         }
       });
   });
+
+  it('should insert default empty block when [] passed as data.blocks', function () {
+    cy.createEditor({
+      data: {
+        blocks: [],
+      },
+    })
+      .as('editorInstance');
+
+    cy.get('[data-cy=editorjs]')
+      .find('.ce-block')
+      .should('have.length', 1);
+  });
+
+  it('should insert default empty block when [] passed via blocks.render() API', function () {
+    cy.createEditor({})
+      .as('editorInstance');
+
+    cy.get<EditorJS>('@editorInstance')
+      .then((editor) => {
+        editor.blocks.render({
+          blocks: [],
+        });
+      });
+
+    cy.get('[data-cy=editorjs]')
+      .find('.ce-block')
+      .should('have.length', 1);
+  });
 });