dump termmeta fieldnames for a termid

//
//Dump termmeta fieldnames to the browser
add_action( 'init' , function() {

    var_dump( get_termmeta_for_term_id( 41 ));

} , 20, 1 );

/**
 * get an array of termmeta fieldnames that actually exist on a termid
 * @param  [type] $termid [description]
 * @return [type]         [description]
 */
function get_termmeta_for_term_id( $termid ) {

    global $wpdb;

    $result = $wpdb->get_results( "SELECT meta_key FROM {$wpdb->prefix}termmeta where term_id = {$termid};" , OBJECT );

    $result = array_map( function( $item ) { return $item->meta_key; } , $result );

    return $result;

}