Add EmptyBlock plugin that prevents adding   in exported data.

packages/ckeditor5-html-support/src/emptyblock.ts

@@ -74,7 +74,7 @@ export default class EmptyBlock extends Plugin {
 	public afterInit(): void {
 		const { model, conversion, plugins, config } = this.editor;
 		const schema = model.schema;
-		const preserveInEditingView = config.get( 'emptyBlock.preserveInEditingView' );
+		const preserveInEditingView = config.get( 'htmlSupport.emptyBlock.preserveInEditingView' );
 
 		schema.extend( '$block', { allowAttributes: [ EMPTY_BLOCK_MODEL_ATTRIBUTE ] } );
 		schema.extend( '$container', { allowAttributes: [ EMPTY_BLOCK_MODEL_ATTRIBUTE ] } );
@@ -99,13 +99,11 @@ export default class EmptyBlock extends Plugin {
 	/**
 	 * Handle clipboard paste events:
 	 *
-	 *	* It does not affect *copying* content from the editor, only *pasting*.
-	 *	* When content is pasted from another editor instance with `<p></p>`,
-	 *	  the `&nbsp;` filler is added, so the getData result is `<p>&nbsp;</p>`.
-	 *	* When content is pasted from the same editor instance with `<p></p>`,
-	 *	  the `&nbsp;` filler is not added, so the getData result is `<p></p>`.
-	 *
-	 * @internal
+	 * * It does not affect *copying* content from the editor, only *pasting*.
+	 * * When content is pasted from another editor instance with `<p></p>`,
+	 *   the `&nbsp;` filler is added, so the getData result is `<p>&nbsp;</p>`.
+	 * * When content is pasted from the same editor instance with `<p></p>`,
+	 *   the `&nbsp;` filler is not added, so the getData result is `<p></p>`.
 	 */
 	private _registerClipboardPastingHandler() {
 		const clipboardPipeline: ClipboardPipeline = this.editor.plugins.get( 'ClipboardPipeline' );

packages/ckeditor5-html-support/src/generalhtmlsupportconfig.ts

@@ -80,4 +80,20 @@ export interface GeneralHtmlSupportConfig {
 	 * ```
 	 */
 	allowEmpty?: Array<string>;
+
+	/**
+	 * The configuration of allowed empty block elements that should not be removed.
+	 *
+	 * The option is used by the {@link module:html-support/emptyblock~EmptyBlock} feature.
+	 */
+	emptyBlock?: {
+
+		/**
+		 * When set to `true`, empty blocks will be preserved in the editing view.
+		 * When `false` (default), empty blocks are only preserved in the data output.
+		 *
+		 * @default false
+		 */
+		preserveInEditingView?: boolean;
+	};
 }

packages/ckeditor5-html-support/tests/emptyblock.js

@@ -332,8 +332,10 @@ describe( 'EmptyBlock', () => {
 
 			editor = await ClassicTestEditor.create( element, {
 				plugins: [ Paragraph, TableEditing, EmptyBlock, Heading, ListEditing, BlockQuote, Clipboard ],
-				emptyBlock: {
-					preserveInEditingView: true
+				htmlSupport: {
+					emptyBlock: {
+						preserveInEditingView: true
+					}
 				}
 			} );
 
@@ -352,8 +354,10 @@ describe( 'EmptyBlock', () => {
 
 			editor = await ClassicTestEditor.create( element, {
 				plugins: [ Paragraph, TableEditing, EmptyBlock, Heading, ListEditing, BlockQuote, Clipboard ],
-				emptyBlock: {
-					preserveInEditingView: false
+				htmlSupport: {
+					emptyBlock: {
+						preserveInEditingView: false
+					}
 				}
 			} );
 

packages/ckeditor5-html-support/tests/manual/emptyblock.js

@@ -26,8 +26,10 @@ function createEditor1( preserveInEditingView ) {
 	return ClassicEditor
 		.create( document.getElementById( 'editor1' ), {
 			...config,
-			emptyBlock: {
-				preserveInEditingView
+			htmlSupport: {
+				emptyBlock: {
+					preserveInEditingView
+				}
 			}
 		} )
 		.then( instance => {