chore(blocks.render): mutex for onchange added to the blocks.render() (#2449)

docs/CHANGELOG.md

@@ -18,6 +18,7 @@
 - `Improvement` - The stub-block style simplified.
 - `Improvement` - If some Block's tool will throw an error during construction, we will show Stub block instead of skipping it during render
 - `Improvement` - Call of `blocks.clear()` now will trigger onChange with "block-removed" event for all removed blocks.
+- `Improvement` - The `blocks.clear()` now can be awaited.
 - `Improvement` - `BlockMutationType` and `BlockMutationEvent` types exported
 - `Improvement` - `blocks.update(id, data)` now can accept partial data object — it will update only passed properties, others will remain the same.
 - `Improvement` - `blocks.update(id, data)` now will trigger onChange with only `block-change` event.

src/components/modules/api/blocks.ts

@@ -18,7 +18,7 @@ export default class BlocksAPI extends Module {
    */
   public get methods(): Blocks {
     return {
-      clear: (): void => this.clear(),
+      clear: (): Promise<void> => this.clear(),
       render: (data: OutputData): Promise<void> => this.render(data),
       renderFromHTML: (data: string): Promise<void> => this.renderFromHTML(data),
       delete: (index?: number): void => this.delete(index),
@@ -172,8 +172,8 @@ export default class BlocksAPI extends Module {
   /**
    * Clear Editor's area
    */
-  public clear(): void {
-    this.Editor.BlockManager.clear(true);
+  public async clear(): Promise<void> {
+    await this.Editor.BlockManager.clear(true);
     this.Editor.InlineToolbar.close();
   }
 
@@ -187,9 +187,16 @@ export default class BlocksAPI extends Module {
       throw new Error('Incorrect data passed to the render() method');
     }
 
-    await this.Editor.BlockManager.clear();
+    /**
+     * Semantic meaning of the "render" method: "Display the new document over the existing one that stays unchanged"
+     * So we need to disable modifications observer temporarily
+     */
+    this.Editor.ModificationsObserver.disable();
 
-    return this.Editor.Renderer.render(data.blocks);
+    await this.Editor.BlockManager.clear();
+    await this.Editor.Renderer.render(data.blocks);
+
+    this.Editor.ModificationsObserver.enable();
   }
 
   /**

test/cypress/tests/onchange.cy.ts

@@ -578,7 +578,7 @@ describe('onChange callback', () => {
     ]);
   });
 
-  it('should be called on blocks.render() on non-empty editor with removed blocks', () => {
+  it('should not be called on blocks.render() on non-empty editor', () => {
     createEditor([
       {
         type: 'paragraph',
@@ -608,14 +608,7 @@ describe('onChange callback', () => {
         }));
       });
 
-    cy.get('@onChange').should('be.calledWithBatchedEvents', [
-      {
-        type: BlockRemovedMutationType,
-      },
-      {
-        type: BlockRemovedMutationType,
-      },
-    ]);
+    cy.get('@onChange').should('have.callCount', 0);
   });
 
   it('should be called on blocks.update() with "block-changed" event', () => {

types/api/blocks.d.ts

@@ -9,7 +9,7 @@ export interface Blocks {
   /**
    * Remove all blocks from Editor zone
    */
-  clear(): void;
+  clear(): Promise<void>;
 
   /**
    * Render passed data