Template part - add patterns placeholder selection.

packages/block-editor/src/components/block-pattern-setup/index.js

@@ -134,6 +134,7 @@ const BlockPatternSetup = ( {
 	blockName,
 	filterPatternsFn,
 	startBlankComponent,
+	onBlockPatternSelect,
 } ) => {
 	const [ viewMode, setViewMode ] = useState( VIEWMODES.carousel );
 	const [ activeSlide, setActiveSlide ] = useState( 0 );
@@ -145,10 +146,12 @@ const BlockPatternSetup = ( {
 		return startBlankComponent;
 	}
 
-	const onBlockPatternSelect = ( blocks ) => {
+	const onBlockPatternSelectDefault = ( blocks ) => {
 		const clonedBlocks = blocks.map( ( block ) => cloneBlock( block ) );
 		replaceBlock( clientId, clonedBlocks );
 	};
+	const onPatternSelectCallback =
+		onBlockPatternSelect || onBlockPatternSelectDefault;
 	return (
 		<div
 			className={ `block-editor-block-pattern-setup view-mode-${ viewMode }` }
@@ -165,7 +168,7 @@ const BlockPatternSetup = ( {
 					setActiveSlide( ( active ) => active - 1 );
 				} }
 				onBlockPatternSelect={ () => {
-					onBlockPatternSelect( patterns[ activeSlide ].blocks );
+					onPatternSelectCallback( patterns[ activeSlide ].blocks );
 				} }
 				onStartBlank={ () => {
 					setShowBlank( true );
@@ -175,7 +178,7 @@ const BlockPatternSetup = ( {
 				viewMode={ viewMode }
 				activeSlide={ activeSlide }
 				patterns={ patterns }
-				onBlockPatternSelect={ onBlockPatternSelect }
+				onBlockPatternSelect={ onPatternSelectCallback }
 			/>
 		</div>
 	);

packages/block-library/src/template-part/edit/index.js

@@ -22,10 +22,10 @@ import { store as editorStore } from '@wordpress/editor';
 /**
  * Internal dependencies
  */
-import TemplatePartInnerBlocks from './inner-blocks';
 import TemplatePartPlaceholder from './placeholder';
 import TemplatePartSelection from './selection';
 import { TemplatePartAdvancedControls } from './advanced-controls';
+import TemplatePartInnerBlocks from './inner-blocks';
 
 export default function TemplatePartEdit( {
 	attributes,
@@ -130,8 +130,8 @@ export default function TemplatePartEdit( {
 				<TagName { ...blockProps }>
 					<TemplatePartPlaceholder
 						area={ attributes.area }
+						clientId={ clientId }
 						setAttributes={ setAttributes }
-						innerBlocks={ innerBlocks }
 					/>
 				</TagName>
 			) }

packages/block-library/src/template-part/edit/placeholder/index.js

@@ -2,7 +2,7 @@
  * WordPress dependencies
  */
 import { __ } from '@wordpress/i18n';
-import { useCallback } from '@wordpress/element';
+import { useCallback, useState } from '@wordpress/element';
 import { useDispatch } from '@wordpress/data';
 import { Placeholder, Dropdown, Button } from '@wordpress/components';
 import { blockDefault } from '@wordpress/icons';
@@ -13,71 +13,98 @@ import { store as coreStore } from '@wordpress/core-data';
  * Internal dependencies
  */
 import TemplatePartSelection from '../selection';
+import PatternsSetup from './patterns-setup';
+
+const PLACEHOLDER_STEPS = {
+	initial: 1,
+	patterns: 2,
+};
 
 export default function TemplatePartPlaceholder( {
 	area,
+	clientId,
 	setAttributes,
-	innerBlocks,
 } ) {
 	const { saveEntityRecord } = useDispatch( coreStore );
-	const onCreate = useCallback( async () => {
-		const title = __( 'Untitled Template Part' );
-		// If we have `area` set from block attributes, means an exposed
-		// block variation was inserted. So add this prop to the template
-		// part entity on creation. Afterwards remove `area` value from
-		// block attributes.
-		const record = {
-			title,
-			slug: 'template-part',
-			content: serialize( innerBlocks ),
-			// `area` is filterable on the server and defaults to `UNCATEGORIZED`
-			// if provided value is not allowed.
-			area,
-		};
-		const templatePart = await saveEntityRecord(
-			'postType',
-			'wp_template_part',
-			record
-		);
-		setAttributes( {
-			slug: templatePart.slug,
-			theme: templatePart.theme,
-			area: undefined,
-		} );
-	}, [ setAttributes, area ] );
+	const [ step, setStep ] = useState( PLACEHOLDER_STEPS.initial );
+
+	const onCreate = useCallback(
+		async ( startingBlocks = [] ) => {
+			const title = __( 'Untitled Template Part' );
+			// If we have `area` set from block attributes, means an exposed
+			// block variation was inserted. So add this prop to the template
+			// part entity on creation. Afterwards remove `area` value from
+			// block attributes.
+			const record = {
+				title,
+				slug: 'template-part',
+				content: serialize( startingBlocks ),
+				// `area` is filterable on the server and defaults to `UNCATEGORIZED`
+				// if provided value is not allowed.
+				area,
+			};
+			const templatePart = await saveEntityRecord(
+				'postType',
+				'wp_template_part',
+				record
+			);
+			setAttributes( {
+				slug: templatePart.slug,
+				theme: templatePart.theme,
+				area: undefined,
+			} );
+		},
+		[ setAttributes, area ]
+	);
 
 	return (
-		<Placeholder
-			icon={ blockDefault }
-			label={ __( 'Template Part' ) }
-			instructions={ __(
-				'Create a new template part or pick an existing one from the list.'
-			) }
-		>
-			<Dropdown
-				contentClassName="wp-block-template-part__placeholder-preview-dropdown-content"
-				position="bottom right left"
-				renderToggle={ ( { isOpen, onToggle } ) => (
-					<>
-						<Button
-							isPrimary
-							onClick={ onToggle }
-							aria-expanded={ isOpen }
-						>
-							{ __( 'Choose existing' ) }
-						</Button>
-						<Button isTertiary onClick={ onCreate }>
-							{ __( 'New template part' ) }
-						</Button>
-					</>
-				) }
-				renderContent={ ( { onClose } ) => (
-					<TemplatePartSelection
-						setAttributes={ setAttributes }
-						onClose={ onClose }
+		<>
+			{ step === PLACEHOLDER_STEPS.initial && (
+				<Placeholder
+					icon={ blockDefault }
+					label={ __( 'Template Part' ) }
+					instructions={ __(
+						'Create a new template part or pick an existing one from the list.'
+					) }
+				>
+					<Dropdown
+						contentClassName="wp-block-template-part__placeholder-preview-dropdown-content"
+						position="bottom right left"
+						renderToggle={ ( { isOpen, onToggle } ) => (
+							<>
+								<Button
+									isPrimary
+									onClick={ onToggle }
+									aria-expanded={ isOpen }
+								>
+									{ __( 'Choose existing' ) }
+								</Button>
+								<Button
+									isTertiary
+									onClick={ () =>
+										setStep( PLACEHOLDER_STEPS.patterns )
+									}
+								>
+									{ __( 'New template part' ) }
+								</Button>
+							</>
+						) }
+						renderContent={ ( { onClose } ) => (
+							<TemplatePartSelection
+								setAttributes={ setAttributes }
+								onClose={ onClose }
+							/>
+						) }
 					/>
-				) }
-			/>
-		</Placeholder>
+				</Placeholder>
+			) }
+			{ step === PLACEHOLDER_STEPS.patterns && (
+				<PatternsSetup
+					area={ area }
+					onCreate={ onCreate }
+					clientId={ clientId }
+				/>
+			) }
+		</>
 	);
 }

packages/block-library/src/template-part/edit/placeholder/patterns-setup.js

@@ -0,0 +1,33 @@
+/**
+ * WordPress dependencies
+ */
+import { __experimentalBlockPatternSetup as BlockPatternSetup } from '@wordpress/block-editor';
+import { useEffect } from '@wordpress/element';
+
+export default function PatternsSetup( { area, clientId, onCreate } ) {
+	const blockNameWithArea = area
+		? `core/template-part/${ area }`
+		: 'core/template-part';
+
+	return (
+		<BlockPatternSetup
+			clientId={ clientId }
+			startBlankComponent={
+				<StartBlankComponent onCreate={ onCreate } />
+			}
+			onBlockPatternSelect={ onCreate }
+			filterPatternsFn={ ( pattern ) =>
+				pattern?.blockTypes?.some?.(
+					( blockType ) => blockType === blockNameWithArea
+				)
+			}
+		/>
+	);
+}
+
+function StartBlankComponent( { onCreate } ) {
+	useEffect( () => {
+		onCreate();
+	}, [] );
+	return null;
+}