a_z_listing_api_handler_defaults( WP_REST_Request $request )

function a_z_listing_api_handler_defaults( WP_REST_Request $request ) {
	$args = array();

	$args['alphabet']      = $request->get_param( 'alphabet' );
	$args['grouping']      = $request->get_param( 'grouping' );
	$args['group-numbers'] = $request->get_param( 'group-numbers' );

	if ( $args['group-numbers'] ) {
		$args['numbers'] = true;
	} else {
		$args['numbers'] = $request->get_param( 'include-numbers' );
	}

	return $args;
}