use v5.12;
use strict;
use warnings;

package MyClass {
    use Moo;

    has _map => (
        is      => 'lazy',
        builder => sub {
            # however you get your list put that here
            return {
                'file1'         => { type => 'file' },
                'somedir/file2' => { type => 'file' },
                'dir1'          => { type => 'dir' },
                'somedir/dir2'  => { type => 'dir' },
                'link1'         => { type => 'link', target => 'somedir/file1' },
                'link2'         => { type => 'link', target => 'otherdir/file3' },
            };
        },
    );

    sub files {
        my $self = shift;
        return [ grep { $self->_map->{$_}{type} eq 'file' } keys %{ $self->_map } ];
    }

    sub directories {
        my $self = shift;
        return [ grep { $self->_map->{$_}{type} eq 'dir' } keys %{ $self->_map } ];
    }

    sub links {
        my $self = shift;
        my @links = grep { $self->_map->{$_}{type} eq 'link' } keys %{ $self->_map };
        return [ map { { $_ => $self->_map->{$_}{target} } } @links ];
    }
};

my $obj = MyClass->new;
say for @{ $obj->directories };

##</code><code>##

dir1
somedir/dir2