use 5.018;
use Data::Dumper;
use JSON::XS;

my @test_data = (
    { Tag1 => "1", Tag2 => "a" },
    { Tag1 => "1", Tag2 => "a" },
    { Tag1 => "1", Tag2 => "b" },
    { Tag1 => "1", Tag2 => "c" },
    { Tag1 => "1", Tag2 => "a" },
    { Tag1 => "2", Tag2 => "a" },
    { Tag1 => "2", Tag2 => "d" },
    { Tag1 => "2", Tag2 => "a" },
    { Tag1 => "3"},
    { Tag1 => "sun", Tag2 => "a" },
    { Tag1 => "sun", Tag2 => "a" },
);

## showing the hashrefs are different regardless of contents
say qq{idx: $_\tref: $test_data[$_]} for 0..2;

my $j = JSON::XS->new->pretty(0)->ascii(1)->canonical(1);

my %seen_items;
my @unique;
for my $item ( @test_data ) {
  my $ser = $j->encode( $item );
  push @unique, $item unless $seen_items{ $ser }++;
}

print Dumper \@unique;
__END__
idx: 0	ref: HASH(0x7fb3ac003ee8)
idx: 1	ref: HASH(0x7fb3ac015cf8)
idx: 2	ref: HASH(0x7fb3ac015dd0)
$VAR1 = [
          {
            'Tag1' => '1',
            'Tag2' => 'a'
          },
          {
            'Tag2' => 'b',
            'Tag1' => '1'
          },
          {
            'Tag1' => '1',
            'Tag2' => 'c'
          },
          {
            'Tag1' => '2',
            'Tag2' => 'a'
          },
          {
            'Tag1' => '2',
            'Tag2' => 'd'
          },
          {
            'Tag1' => '3'
          },
          {
            'Tag1' => 'sun',
            'Tag2' => 'a'
          }
        ];