add_action( 'graphql_register_types', function() {


register_graphql_field( 'RootQuery', 'siteLogo', [
'type' => 'MediaItem',
'description' => __( 'The logo set in the customizer', 'your-textdomain' ),
'resolve' => function() {

$logo_id = get_theme_mod( 'custom_logo' );

if ( ! isset( $logo_id ) || ! absint( $logo_id ) ) {
return null;
}

$media_object = get_post( $logo_id );
return new \WPGraphQL\Model\Post( $media_object );

}
] );

} );