Fixes wp-graphql#76

Author: Twansparant

src/class-config.php

@@ -48,6 +48,7 @@ public function init( \WPGraphQL\Registry\TypeRegistry $type_registry ) {
 		$this->add_acf_fields_to_individual_posts();
 		$this->add_acf_fields_to_users();
 		$this->add_acf_fields_to_options_pages();
+		$this->add_acf_fields_to_pages();
 	}
 
 	/**
@@ -1728,4 +1729,100 @@ protected function add_acf_fields_to_options_pages() {
 		}
 	}
 
+	/**
+	 * Add field groups for `page_type` and `page_template`.
+	 * Note that these will show up for all pages in the schema,
+	 * they will not be limited to the page types or templates assigned in the field group.
+	 */
+	protected function add_acf_fields_to_pages() {
+
+		$page_field_groups = [];
+
+		/**
+		 * Get the field groups.
+		 *
+		 * TODO: Can we filter this to only page related ACF Field Groups?
+		 */
+		$field_groups = acf_get_field_groups();
+
+		/**
+		 * We only want to add field groups for page type and template params.
+		 * Page by location is already covered by `add_acf_fields_to_individual_posts`,
+		 * so we do not want to duplicate that.
+		 */
+		$allowed_page_params = [
+			'page_type',
+			'page_template',
+		];
+
+		foreach ( $field_groups as $field_group ) {
+			if ( ! empty( $field_group['location'] ) && is_array( $field_group['location'] ) ) {
+				foreach ( $field_group['location'] as $locations ) {
+					if ( ! empty( $locations ) && is_array( $locations ) ) {
+						foreach ( $locations as $location ) {
+
+							/**
+							 * If the operator is not equal to, we don't need to do anything,
+							 * so we can just continue
+							 */
+							if ( '!=' === $location['operator'] ) {
+								continue;
+							}
+
+							/**
+							 * Add field group if the param is page related.
+							 */
+							if ( in_array( $location['param'], $allowed_page_params, true ) && '==' === $location['operator'] ) {
+								$page_field_groups[] = [
+									'type'        => $location['param'],
+									'field_group' => $field_group,
+									'post_id'     => $location['value']
+								];
+							}
+						}
+					}
+				}
+			}
+		}
+
+
+		/**
+		 * If no field groups are assigned to pages, we don't need to modify the Schema.
+		 */
+		if ( empty( $page_field_groups ) ) {
+			return;
+		}
+
+		/**
+		 * Loop over the field groups assigned to pages
+		 * and register them to the Schema
+		 */
+		foreach ( $page_field_groups as $key => $group ) {
+
+			if ( empty( $group['field_group'] ) || ! is_array( $group['field_group'] ) ) {
+				continue;
+			}
+
+			// Initialize our field group object.
+			$field_group = $group['field_group'];
+
+			$page_type_object = get_post_type_object('page');
+
+			$field_name = isset( $field_group['graphql_field_name'] ) ? $field_group['graphql_field_name'] : Config::camel_case( $field_group['title'] );
+			$field_group['type'] = 'group';
+			$field_group['name'] = $field_name;
+			$description         = $field_group['description'] ? $field_group['description'] . ' | ' : '';
+			$config              = [
+				'name'            => $field_name,
+				'description'     => $description,
+				'acf_field'       => $field_group,
+				'acf_field_group' => null,
+				'resolve'         => function( $root ) use ( $field_group ) {
+					return isset( $root ) ? $root : null;
+				}
+			];
+
+			$this->register_graphql_field($page_type_object->graphql_single_name, $field_name, $config);
+		}
+	}
 }