Add more taxonomy options to the post navigation link

docs/reference-guides/core-blocks.md

@@ -642,7 +642,7 @@ Displays the next or previous post link that is adjacent to the current post. ([
 -	**Name:** core/post-navigation-link
 -	**Category:** theme
 -	**Supports:** color (background, link, text), typography (fontSize, lineHeight), ~~html~~, ~~reusable~~
--	**Attributes:** arrow, label, linkLabel, showTitle, textAlign, type
+-	**Attributes:** arrow, excludedTerms, inSameTerm, label, linkLabel, showTitle, taxonomy, textAlign, type
 
 ## Post Template
 

packages/block-library/src/post-navigation-link/block.json

@@ -28,6 +28,16 @@
 		"arrow": {
 			"type": "string",
 			"default": "none"
+		},
+		"excludedTerms": {
+			"type": "string"
+		},
+		"inSameTerm": {
+			"type": "boolean"
+		},
+		"taxonomy": {
+			"type": "string",
+			"default": ""
 		}
 	},
 	"supports": {

packages/block-library/src/post-navigation-link/edit.js

@@ -10,7 +10,9 @@ import {
 	__experimentalToggleGroupControl as ToggleGroupControl,
 	__experimentalToggleGroupControlOption as ToggleGroupControlOption,
 	ToggleControl,
+	SelectControl,
 	PanelBody,
+	__experimentalInputControl as InputControl,
 } from '@wordpress/components';
 import {
 	InspectorControls,
@@ -20,9 +22,20 @@ import {
 	useBlockProps,
 } from '@wordpress/block-editor';
 import { __, _x } from '@wordpress/i18n';
+import { useSelect } from '@wordpress/data';
+import { store as coreStore } from '@wordpress/core-data';
 
 export default function PostNavigationLinkEdit( {
-	attributes: { type, label, showTitle, textAlign, linkLabel, arrow },
+	attributes: {
+		type,
+		label,
+		showTitle,
+		textAlign,
+		linkLabel,
+		arrow,
+		taxonomy,
+		excludedTerms,
+	},
 	setAttributes,
 } ) {
 	const isNext = type === 'next';
@@ -47,6 +60,44 @@ export default function PostNavigationLinkEdit( {
 			[ `has-text-align-${ textAlign }` ]: textAlign,
 		} ),
 	} );
+
+	// We need to know the post type in order to get all supported taxonomies.
+	const postType = useSelect(
+		// FIXME: @wordpress/block-library should not depend on @wordpress/editor.
+		// Blocks can be loaded into a *non-post* block editor.
+		// eslint-disable-next-line @wordpress/data-no-store-string-literals
+		( select ) => select( 'core/editor' ).getCurrentPostType(),
+		[]
+	);
+	const taxonomies = useSelect(
+		( select ) => {
+			const { getTaxonomies } = select( coreStore );
+			const filteredTaxonomies = getTaxonomies( {
+				type: postType,
+				per_page: -1,
+				context: 'view',
+			} );
+			return filteredTaxonomies;
+		},
+		[ postType ]
+	);
+	const getTaxonomyOptions = () => {
+		const selectOption = {
+			label: __( 'Unfiltered' ),
+			value: '',
+		};
+		const taxonomyOptions = ( taxonomies ?? [] )
+			.filter( ( tax ) => tax.slug !== 'nav_menu' )
+			.map( ( item ) => {
+				return {
+					value: item.slug,
+					label: item.name,
+				};
+			} );
+
+		return [ selectOption, ...taxonomyOptions ];
+	};
+
 	return (
 		<>
 			<InspectorControls>
@@ -113,6 +164,32 @@ export default function PostNavigationLinkEdit( {
 						/>
 					</ToggleGroupControl>
 				</PanelBody>
+				<PanelBody title={ __( 'Filters' ) }>
+					<SelectControl
+						label={ __( 'Filter by taxonomy' ) }
+						value={ taxonomy }
+						options={ getTaxonomyOptions() }
+						onChange={ ( value ) =>
+							setAttributes( {
+								taxonomy: value,
+								inSameTerm: value === '' ? false : true,
+							} )
+						}
+						help={ __(
+							'Only link to posts that have the same taxonomy terms as the current post. For example the same categories.'
+						) }
+					/>
+					<InputControl
+						label={ __( 'Add terms to exclude' ) }
+						value={ excludedTerms }
+						onChange={ ( value ) =>
+							setAttributes( { excludedTerms: value } )
+						}
+						help={ __(
+							'Exclude terms from any taxonomy by entering the term name, slug, or ID. Separate multiple terms with a comma. Posts with excluded terms will not be linked to, even if they have other matching terms.'
+						) }
+					/>
+				</PanelBody>
 			</InspectorControls>
 			<BlockControls>
 				<AlignmentToolbar

packages/block-library/src/post-navigation-link/index.php

@@ -99,10 +99,42 @@ function render_block_core_post_navigation_link( $attributes, $content ) {
 		}
 	}
 
+	$in_same_term   = isset( $attributes['inSameTerm'] ) ? $attributes['inSameTerm'] : false;
+	$taxonomy       = isset( $attributes['taxonomy'] ) && $in_same_term ? $attributes['taxonomy'] : '';
+	$excluded_terms = '';
+
 	// The dynamic portion of the function name, `$navigation_type`,
 	// refers to the type of adjacency, 'next' or 'previous'.
 	$get_link_function = "get_{$navigation_type}_post_link";
-	$content           = $get_link_function( $format, $link );
+
+	// Get the term id of each excluded term.
+	if ( isset( $attributes['excludedTerms'] ) && ! empty( $attributes['excludedTerms'] ) ) {
+		$excluded_terms = explode( ',', sanitize_text_field( $attributes['excludedTerms'] ) );
+		// Get the taxonomies of the current post type.
+		$taxonomies = get_object_taxonomies( get_post_type() );
+		// The user may have entered the taxonomy slug, name or id.
+		$types  = array( 'slug', 'name', 'term_id', 'id', 'ID', 'term_taxonomy_id' );
+		$result = array();
+		foreach ( $excluded_terms as $term ) {
+			$term = trim( $term );
+			foreach ( $taxonomies as $tax ) {
+				foreach ( $types as $type ) {
+					$termid = get_term_by( $type, $term, $tax );
+					if ( $termid ) {
+						$result[] = $termid->term_taxonomy_id;
+					}
+				}
+			}
+		}
+		$excluded_terms = array_unique( $result );
+	}
+
+	if ( $in_same_term ) {
+		$content = $get_link_function( $format, $link, $in_same_term, $excluded_terms, $taxonomy );
+	} else {
+		$content = $get_link_function( $format, $link, '', $excluded_terms );
+	}
+
 	return sprintf(
 		'<div %1$s>%2$s</div>',
 		$wrapper_attributes,

test/integration/fixtures/blocks/core__post-navigation-link.json

@@ -6,7 +6,8 @@
 			"type": "next",
 			"showTitle": false,
 			"linkLabel": false,
-			"arrow": "none"
+			"arrow": "none",
+			"taxonomy": ""
 		},
 		"innerBlocks": []
 	}