Page List: Respect the selected parent page when converting to a list of navigation links

packages/block-library/src/page-list/edit.js

@@ -182,11 +182,6 @@ export default function PageListEdit( {
 		pages?.length > 0 &&
 		pages?.length <= MAX_PAGE_COUNT;
 
-	const convertToNavigationLinks = useConvertToNavigationLinks( {
-		clientId,
-		pages,
-	} );
-
 	const pagesByParentId = useMemo( () => {
 		if ( pages === null ) {
 			return new Map();
@@ -213,6 +208,12 @@ export default function PageListEdit( {
 		}, new Map() );
 	}, [ pages ] );
 
+	const convertToNavigationLinks = useConvertToNavigationLinks( {
+		clientId,
+		pages,
+		parentPageID,
+	} );
+
 	const blockProps = useBlockProps( {
 		className: classnames( 'wp-block-page-list', {
 			'has-text-color': !! context.textColor,

packages/block-library/src/page-list/test/convert-to-links-modal.js

@@ -383,5 +383,139 @@ describe( 'page list convert to links', () => {
 				},
 			] );
 		} );
+
+		it( 'Can use a different parent page', () => {
+			const pages = [
+				{
+					title: {
+						raw: 'Sample Page',
+						rendered: 'Sample Page',
+					},
+					id: 2,
+					parent: 0,
+					link: 'http://wordpress.local/sample-page/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'About',
+						rendered: 'About',
+					},
+					id: 34,
+					parent: 0,
+					link: 'http://wordpress.local/about/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'Contact Page',
+						rendered: 'Contact Page',
+					},
+					id: 37,
+					parent: 0,
+					link: 'http://wordpress.local/contact-page/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'Test',
+						rendered: 'Test',
+					},
+					id: 229,
+					parent: 0,
+					link: 'http://wordpress.local/test/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'About Sub 1',
+						rendered: 'About Sub 1',
+					},
+					id: 738,
+					parent: 34,
+					link: 'http://wordpress.local/about/about-sub-1/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'About Sub 2',
+						rendered: 'About Sub 2',
+					},
+					id: 740,
+					parent: 34,
+					link: 'http://wordpress.local/about/about-sub-2/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'Test Sub',
+						rendered: 'Test Sub',
+					},
+					id: 742,
+					parent: 229,
+					link: 'http://wordpress.local/test/test-sub/',
+					type: 'page',
+				},
+				{
+					title: {
+						raw: 'Test Sub Sub',
+						rendered: 'Test Sub Sub',
+					},
+					id: 744,
+					parent: 742,
+					link: 'http://wordpress.local/test/test-sub/test-sub-sub/',
+					type: 'page',
+				},
+			];
+
+			const convertLinksWithParentOneLevel = convertToNavigationLinks(
+				pages,
+				34
+			);
+
+			expect( convertLinksWithParentOneLevel ).toEqual( [
+				{
+					attributes: {
+						id: 738,
+						kind: 'post-type',
+						label: 'About Sub 1',
+						type: 'page',
+						url: 'http://wordpress.local/about/about-sub-1/',
+					},
+					innerBlocks: [],
+					name: 'core/navigation-link',
+				},
+				{
+					attributes: {
+						id: 740,
+						kind: 'post-type',
+						label: 'About Sub 2',
+						type: 'page',
+						url: 'http://wordpress.local/about/about-sub-2/',
+					},
+					innerBlocks: [],
+					name: 'core/navigation-link',
+				},
+			] );
+
+			const convertLinksWithParentTwoLevels = convertToNavigationLinks(
+				pages,
+				742
+			);
+
+			expect( convertLinksWithParentTwoLevels ).toEqual( [
+				{
+					attributes: {
+						id: 744,
+						kind: 'post-type',
+						label: 'Test Sub Sub',
+						type: 'page',
+						url: 'http://wordpress.local/test/test-sub/test-sub-sub/',
+					},
+					innerBlocks: [],
+					name: 'core/navigation-link',
+				},
+			] );
+		} );
 	} );
 } );

packages/block-library/src/page-list/use-convert-to-navigation-links.js

@@ -5,7 +5,14 @@ import { createBlock } from '@wordpress/blocks';
 import { useSelect, useDispatch } from '@wordpress/data';
 import { store as blockEditorStore } from '@wordpress/block-editor';
 
-export function convertToNavigationLinks( pages = [] ) {
+/**
+ * Converts an array of pages into a nested array of navigation link blocks.
+ *
+ * @param {Array} pages An array of pages.
+ *
+ * @return {Array} A nested array of navigation link blocks.
+ */
+function createNavigationLinks( pages = [] ) {
 	const linkMap = {};
 	const navigationLinks = [];
 	pages.forEach( ( { id, title, link: url, type, parent } ) => {
@@ -30,11 +37,61 @@ export function convertToNavigationLinks( pages = [] ) {
 				// Use a placeholder if the child appears before parent in list.
 				linkMap[ parent ] = { innerBlocks: [] };
 			}
+			// Although these variables are not referenced, they are needed to store the innerBlocks in memory.
 			const parentLinkInnerBlocks = linkMap[ parent ].innerBlocks;
 			parentLinkInnerBlocks.push( linkMap[ id ] );
 		}
 	} );
 
+	return navigationLinks;
+}
+
+/**
+ * Finds a navigation link block by id, recursively.
+ * It might be possible to make this a more generic helper function.
+ *
+ * @param {Array}  navigationLinks An array of navigation link blocks.
+ * @param {number} id              The id of the navigation link to find.
+ *
+ * @return {Object|null} The navigation link block with the given id.
+ */
+function findNavigationLinkById( navigationLinks, id ) {
+	for ( const navigationLink of navigationLinks ) {
+		// Is this the link we're looking for?
+		if ( navigationLink.attributes.id === id ) {
+			return navigationLink;
+		}
+
+		// If not does it have innerBlocks?
+		if ( navigationLink.innerBlocks && navigationLink.innerBlocks.length ) {
+			const foundNavigationLink = findNavigationLinkById(
+				navigationLink.innerBlocks,
+				id
+			);
+
+			if ( foundNavigationLink ) {
+				return foundNavigationLink;
+			}
+		}
+	}
+
+	return null;
+}
+
+export function convertToNavigationLinks( pages = [], parentPageID = null ) {
+	let navigationLinks = createNavigationLinks( pages );
+
+	// If a parent page ID is provided, only return the children of that page.
+	if ( parentPageID ) {
+		const parentPage = findNavigationLinkById(
+			navigationLinks,
+			parentPageID
+		);
+		if ( parentPage && parentPage.innerBlocks ) {
+			navigationLinks = parentPage.innerBlocks;
+		}
+	}
+
 	// Transform all links with innerBlocks into Submenus. This can't be done
 	// sooner because page objects have no information on their children.
 	const transformSubmenus = ( listOfLinks ) => {
@@ -53,11 +110,14 @@ export function convertToNavigationLinks( pages = [] ) {
 	};
 
 	transformSubmenus( navigationLinks );
-
 	return navigationLinks;
 }
 
-export function useConvertToNavigationLinks( { clientId, pages } ) {
+export function useConvertToNavigationLinks( {
+	clientId,
+	pages,
+	parentPageID,
+} ) {
 	const { replaceBlock, selectBlock } = useDispatch( blockEditorStore );
 
 	const { parentNavBlockClientId } = useSelect(
@@ -79,7 +139,7 @@ export function useConvertToNavigationLinks( { clientId, pages } ) {
 	);
 
 	return () => {
-		const navigationLinks = convertToNavigationLinks( pages );
+		const navigationLinks = convertToNavigationLinks( pages, parentPageID );
 
 		// Replace the Page List block with the Navigation Links.
 		replaceBlock( clientId, navigationLinks );