Just for fun :)

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11160123
use warnings;
use Data::Dump qw( pp );

my $VAR1 = {                   # wanted
          'hk1' => 5,
          'hk2' => [
                     [1, 2, 3],
                     [4, 5, 8]
                   ],
          };
#push @{$VAR1->{hk2}[0]}, "001" .. "010";
#$VAR1 = [ map [ $_ .. $_+29 ], 1 .. 11 ];
$Data::Dump::LINEWIDTH = 100;

print "Original:\n\n";
my $orig = pp $VAR1;
print "$orig\n";

print "\nThe new dump string:\n\n";
my $dump = arraysofscalarsonasingleline( $VAR1 );
print $dump;

print "\n\nValidation of the new dump:\n\n";
my $test = pp eval $dump;
print "$test\n";
print "\n", $orig eq $test
  ? "\e[92m VALID :)\e[m"
  : "\e[91m ERROR: Validation failed :(\e[m", "\n";

######################################################################
+#########

sub arraysofscalarsonasingleline
  {
  if( @_ > 1 )
    {
    my @elements = map arraysofscalarsonasingleline($_), @_;
    return "(\n" . join(",\n", @elements) =~ s/^/  /gmr . "\n)";
    }
  my $item = shift;
  if( 'HASH' eq ref $item )
    {
    my @elements = map
      { my $key = arraysofscalarsonasingleline( $_ );
        ref($item->{$_})
          ?  "$key =>\n" . arraysofscalarsonasingleline( $item->{$_} )
+ =~ s/^/  /gmr
          : "$key => " . arraysofscalarsonasingleline( $item->{$_} )
      } sort keys %$item;
    return "{\n" . join(",\n", @elements) =~ s/^/  /gmr . "\n}";
    }
  elsif( 'ARRAY' eq ref $item )
    {
    if( grep { ref } @$item and @$item > 1 )
      {
      my @elements = join ",\n", map arraysofscalarsonasingleline( $_ 
+), @$item;
      return "[\n" . join(",\n", @elements) =~ s/^/  /gmr . "\n]";
      }
    else
      {
      my @elements = join ', ', map arraysofscalarsonasingleline( $_ )
+, @$item;
      return "[ @elements ]";
      }
    }
  else
    {
    use Data::Dump 'pp';
    return pp $item;
    }
  }
[download]

Outputs:

Original:

{ hk1 => 5, hk2 => [[1, 2, 3], [4, 5, 8]] }

The new dump string:

{
  "hk1" => 5,
  "hk2" =>
    [
      [ 1, 2, 3 ],
      [ 4, 5, 8 ]
    ]
}

Validation of the new dump:

{ hk1 => 5, hk2 => [[1, 2, 3], [4, 5, 8]] }

 VALID :)
[download]