Fix: Backspace on a fully selected content or at the beginning of the…

… first block will ensure that paragraph is left.

src/deletecommand.js

@@ -10,6 +10,9 @@
 import Command from '@ckeditor/ckeditor5-core/src/command';
 import Selection from '@ckeditor/ckeditor5-engine/src/model/selection';
 import ChangeBuffer from './changebuffer';
+import Position from '@ckeditor/ckeditor5-engine/src/model/position';
+import Element from '@ckeditor/ckeditor5-engine/src/model/element';
+import Range from '@ckeditor/ckeditor5-engine/src/model/range';
 import count from '@ckeditor/ckeditor5-utils/src/count';
 
 /**
@@ -60,6 +63,8 @@ export default class DeleteCommand extends Command {
 	execute( options = {} ) {
 		const doc = this.editor.document;
 		const dataController = this.editor.data;
+		const root = doc.getRoot();
+		const schema = doc.schema;
 
 		doc.enqueueChanges( () => {
 			this._buffer.lock();
@@ -90,6 +95,25 @@ export default class DeleteCommand extends Command {
 			doc.selection.setRanges( selection.getRanges(), selection.isBackward );
 
 			this._buffer.unlock();
+
+			// Check whether the whole content has been removed and whether schema allows inserting a paragraph.
+			// If the user will typing after removing the whole content, the user's input should be wrapped in the paragraph
+			// instead of any other element. See https://github.com/ckeditor/ckeditor5-typing/issues/61.
+			if (
+				Position.createAt( root ).isTouching( selection.getFirstPosition() ) &&
+				Position.createAt( root, 'end' ).isTouching( selection.getLastPosition() ) &&
+				schema.check( { name: 'paragraph', inside: root.name } )
+			) {
+				this._buffer.batch.remove(
+					new Range( new Position( root, [ 0 ] ), new Position( root, [ 1 ] ) )
+				);
+
+				this._buffer.batch.insert(
+					new Position( root, [ 0 ] ), new Element( 'paragraph' )
+				);
+
+				doc.selection.setRanges( new Range( new Position( root, [ 0 ] ) ) );
+			}
 		} );
 	}
 }

tests/inputcommand-integration.js

@@ -13,6 +13,7 @@ import Undo from '@ckeditor/ckeditor5-undo/src/undo';
 import Bold from '@ckeditor/ckeditor5-basic-styles/src/bold';
 import Italic from '@ckeditor/ckeditor5-basic-styles/src/italic';
 import Enter from '@ckeditor/ckeditor5-enter/src/enter';
+import Heading from '@ckeditor/ckeditor5-heading/src/heading';
 
 import Range from '@ckeditor/ckeditor5-engine/src/model/range';
 import Position from '@ckeditor/ckeditor5-engine/src/model/position';
@@ -28,7 +29,7 @@ describe( 'InputCommand integration', () => {
 		document.body.appendChild( editorElement );
 
 		return ClassicTestEditor.create( editorElement, {
-			plugins: [ Typing, Paragraph, Undo, Bold, Italic, Enter ],
+			plugins: [ Typing, Paragraph, Undo, Bold, Italic, Enter, Heading ],
 			typing: { undoStep: 3 }
 		} )
 		.then( newEditor => {
@@ -210,5 +211,45 @@ describe( 'InputCommand integration', () => {
 			expectOutput( '<paragraph>Foo <$text bold="true">B[]</$text> Bar</paragraph>',
 				'<p>Foo <strong>B{}</strong> Bar</p>' );
 		} );
+
+		// See https://github.com/ckeditor/ckeditor5-typing/issues/61.
+		it( 'leaves an empty paragraph after removing the whole content from editor #1', () => {
+			setModelData( doc, '[<heading1>Header 1</heading1><paragraph>Some text.</paragraph>]' );
+
+			editor.execute( 'delete' );
+
+			expectOutput( '<paragraph>[]</paragraph>', '<p>[]</p>' );
+		} );
+
+		// See https://github.com/ckeditor/ckeditor5-typing/issues/61.
+		it( 'leaves an empty paragraph after removing the whole content from editor #2', () => {
+			setModelData( doc, '<heading1>[Header 1</heading1><paragraph>Some text.]</paragraph>' );
+
+			editor.execute( 'delete' );
+
+			expectOutput( '<paragraph>[]</paragraph>', '<p>[]</p>' );
+		} );
+
+		// See https://github.com/ckeditor/ckeditor5-typing/issues/61.
+		it( 'wraps inserted text in a paragraph after typing in editor with selected the whole content #1', () => {
+			setModelData( doc, '[<heading1>Header 1</heading1><paragraph>Some text.</paragraph>]' );
+
+			editor.execute( 'delete' );
+
+			simulateTyping( '123' );
+
+			expectOutput( '<paragraph>123[]</paragraph>', '<p>123{}</p>' );
+		} );
+
+		// See https://github.com/ckeditor/ckeditor5-typing/issues/61.
+		it( 'wraps inserted text in a paragraph after typing in editor with selected the whole content #2', () => {
+			setModelData( doc, '<heading1>[Header 1</heading1><paragraph>Some text.]</paragraph>' );
+
+			editor.execute( 'delete' );
+
+			simulateTyping( '123' );
+
+			expectOutput( '<paragraph>123[]</paragraph>', '<p>123{}</p>' );
+		} );
 	} );
 } );