Format duration in Perl6

format.p6

sub format-duration(Duration:D $d --> Str) {                                                                                                                                                                         
    join "", reverse ($d.Rat.polymod(60, 60, 24) Z <s m h d>).grep:{$_[0] != 0} or "0s"                                                                                                                              
}

sub format-duration2(Duration:D $d --> Str) {
    ($d.Rat.polymod(60, 60, 24) Z <s m h d>).grep({$_[0] != 0}).reverse.flat.join("") or "0s";
}