Sticky Position: Add a "Make sticky" action to the Template Part block

packages/block-editor/src/private-apis.js

@@ -7,6 +7,11 @@ import { lock } from './lock-unlock';
 import OffCanvasEditor from './components/off-canvas-editor';
 import LeafMoreMenu from './components/off-canvas-editor/leaf-more-menu';
 import { ComposedPrivateInserter as PrivateInserter } from './components/inserter';
+import { default as useConvertToGroupButtonProps } from './components/convert-to-group-buttons/use-convert-to-group-button-props';
+import {
+	hasStickyPositionSupport,
+	useIsPositionDisabled,
+} from './hooks/position';
 
 /**
  * Private @wordpress/block-editor APIs.
@@ -18,4 +23,7 @@ lock( privateApis, {
 	LeafMoreMenu,
 	OffCanvasEditor,
 	PrivateInserter,
+	useConvertToGroupButtonProps,
+	hasStickyPositionSupport,
+	useIsPositionDisabled,
 } );

packages/edit-site/src/components/template-part-converter/convert-to-sticky-group.js

@@ -0,0 +1,97 @@
+/**
+ * WordPress dependencies
+ */
+import { switchToBlockType } from '@wordpress/blocks';
+import { MenuItem } from '@wordpress/components';
+import { useSelect, useDispatch } from '@wordpress/data';
+import {
+	store as blockEditorStore,
+	privateApis as blockEditorPrivateApis,
+} from '@wordpress/block-editor';
+import { __ } from '@wordpress/i18n';
+
+/**
+ * Internal dependencies
+ */
+import { unlock } from '../../private-apis';
+
+const {
+	hasStickyPositionSupport,
+	useConvertToGroupButtonProps,
+	useIsPositionDisabled,
+} = unlock( blockEditorPrivateApis );
+
+export default function ConvertToStickyGroup( { selectedClientIds, onClose } ) {
+	const { replaceBlocks } = useDispatch( blockEditorStore );
+	const { clientIds, isGroupable, blocksSelection, groupingBlockName } =
+		useConvertToGroupButtonProps( selectedClientIds );
+
+	const { canRemove, hasParents } = useSelect(
+		( select ) => {
+			const { getBlockParents, canRemoveBlocks } =
+				select( blockEditorStore );
+			return {
+				canRemove: canRemoveBlocks( clientIds ),
+				hasParents: !! getBlockParents( clientIds[ 0 ] ).length,
+			};
+		},
+		[ clientIds ]
+	);
+
+	const isPositionDisabled = useIsPositionDisabled( {
+		name: groupingBlockName,
+	} );
+	const isStickySupported = hasStickyPositionSupport( groupingBlockName );
+
+	const onConvertToGroup = () => {
+		const newBlocks = switchToBlockType(
+			blocksSelection,
+			groupingBlockName
+		);
+
+		if ( newBlocks && newBlocks.length > 0 ) {
+			// Because the block is not in the store yet we can't use
+			// updateBlockAttributes so need to manually update attributes.
+			newBlocks[ 0 ].attributes.layout = {
+				type: 'default',
+			};
+			newBlocks[ 0 ].attributes.style = {
+				...( newBlocks[ 0 ].attributes.style || {} ),
+				position: {
+					type: 'sticky',
+					top: '0px',
+				},
+			};
+			replaceBlocks( clientIds, newBlocks );
+		}
+	};
+
+	// For the button to be visible, the following conditions must be met:
+	// - The block is groupable.
+	// - The block can be removed.
+	// - A grouping block is available.
+	// - The block and theme both support sticky position.
+	// - The block has no parents, so is at the root of the template.
+	if (
+		! isGroupable ||
+		! canRemove ||
+		! groupingBlockName ||
+		! isStickySupported ||
+		hasParents ||
+		isPositionDisabled
+	) {
+		return null;
+	}
+
+	// Allow converting a single template part block to a group.
+	return (
+		<MenuItem
+			onClick={ () => {
+				onConvertToGroup();
+				onClose();
+			} }
+		>
+			{ __( 'Make sticky' ) }
+		</MenuItem>
+	);
+}

packages/edit-site/src/components/template-part-converter/index.js

@@ -12,6 +12,7 @@ import {
  */
 import ConvertToRegularBlocks from './convert-to-regular';
 import ConvertToTemplatePart from './convert-to-template-part';
+import { default as ConvertToStickyGroup } from './convert-to-sticky-group';
 
 export default function TemplatePartConverter() {
 	return (
@@ -36,10 +37,16 @@ function TemplatePartConverterMenuItem( { clientIds, onClose } ) {
 	// Allow converting a single template part to standard blocks.
 	if ( blocks.length === 1 && blocks[ 0 ]?.name === 'core/template-part' ) {
 		return (
-			<ConvertToRegularBlocks
-				clientId={ clientIds[ 0 ] }
-				onClose={ onClose }
-			/>
+			<>
+				<ConvertToRegularBlocks
+					clientId={ clientIds[ 0 ] }
+					onClose={ onClose }
+				/>
+				<ConvertToStickyGroup
+					selectedClientIds={ clientIds }
+					onClose={ onClose }
+				/>
+			</>
 		);
 	}
 	return <ConvertToTemplatePart clientIds={ clientIds } blocks={ blocks } />;