feat: Add support for CoreNavigation blocks

.changeset/thirty-ducks-check.md

@@ -0,0 +1,63 @@
+---
+"@wpengine/wp-graphql-content-blocks": minor
+---
+
+Adds support for resolving and returning navigation items within the CoreNavigation innerBlocks for WPGraphQL Content Blocks.
+
+```graphql
+{
+  posts {
+    nodes {
+      editorBlocks {
+        ... on CoreNavigation {
+          type
+          name
+          innerBlocks {
+            type
+            name
+          }
+          attributes {
+            ref
+          }
+        }
+      }
+    }
+  }
+}
+```
+```json
+{
+  "data": {
+    "posts": {
+      "nodes": [
+        {
+          "editorBlocks": [
+            {
+              "type": "CoreNavigation",
+              "name": "core/navigation",
+              "innerBlocks": [
+                {
+                  "type": "CorePageList",
+                  "name": "core/page-list"
+                },
+                {
+                  "type": "CoreNavigationLink",
+                  "name": "core/navigation-link"
+                }
+              ],
+              "attributes": {
+                "ref": 31
+              }
+            },
+          ]
+        },
+        {
+          "editorBlocks": [
+            {}
+          ]
+        }
+      ]
+    }
+  },
+}
+```

includes/Data/ContentBlocksResolver.php

@@ -152,6 +152,7 @@ private static function handle_do_block( array $block ): ?array {
 		$block = self::populate_post_content_inner_blocks( $block );
 		$block = self::populate_reusable_blocks( $block );
 		$block = self::populate_pattern_inner_blocks( $block );
+		$block = self::populate_navigation_blocks( $block );
 
 		// Prepare innerBlocks.
 		if ( ! empty( $block['innerBlocks'] ) ) {
@@ -242,6 +243,34 @@ private static function populate_post_content_inner_blocks( array $block ): arra
 		return $block;
 	}
 
+	/**
+	 * Populates the innerBlocks of this block with navigation item blocks from the referenced navigation post.
+	 *
+	 * @param array<string,mixed> $block The block to populate.
+	 *
+	 * @return array<string,mixed> The populated block.
+	 */
+	private static function populate_navigation_blocks( array $block ): array {
+		if ( 'core/navigation' !== $block['blockName'] || ! isset( $block['attrs']['ref'] ) ) {
+			return $block;
+		}
+
+		$ref             = absint( $block['attrs']['ref'] );
+		$navigation_post = get_post( $ref );
+
+		if ( ! $navigation_post || 'publish' !== $navigation_post->post_status ) {
+			return $block;
+		}
+
+		$parsed_blocks = ! empty( $navigation_post->post_content ) ? parse_blocks( $navigation_post->post_content ) : null;
+
+		if ( empty( $parsed_blocks ) ) {
+			return $block;
+		}
+		$block['innerBlocks'] = $parsed_blocks;
+		return $block;
+	}
+
 	/**
 	 * Populates reusable blocks with the blocks from the reusable ref ID.
 	 *