Mojo::JSON: encode core boolean values as json bools

On perl 5.36 and newer, perl's own boolean values can be identified as
being booleans. Encode them as JSON boolean values when possible.

lib/Mojo/JSON.pm

@@ -12,6 +12,12 @@ use constant JSON_XS => $ENV{MOJO_NO_JSON_XS}
   ? 0
   : !!eval { require Cpanel::JSON::XS; Cpanel::JSON::XS->VERSION('4.09'); 1 };
 
+use constant CORE_BOOLS => defined &builtin::is_bool;
+
+BEGIN {
+  warnings->unimport('experimental::builtin') if CORE_BOOLS;
+}
+
 our @EXPORT_OK = qw(decode_json encode_json false from_json j to_json true);
 
 # Escaped special character map
@@ -250,6 +256,9 @@ sub _encode_value {
   # Null
   return 'null' unless defined $value;
 
+  # Boolean
+  return $value ? 'true' : 'false' if CORE_BOOLS && builtin::is_bool($value);
+
   # Number
   no warnings 'numeric';
   return $value

t/mojo/json.t

@@ -218,6 +218,14 @@ subtest 'Encode number' => sub {
   is $bytes, '23.3', 'encode 23.3';
 };
 
+subtest 'Encode boolean' => sub {
+  plan skip_all => 'No core boolean support' if !defined &builtin::is_bool;
+  my $bytes = encode_json [!!1];
+  is $bytes, '[true]', 'encode [!!1]';
+  $bytes = encode_json [!!0];
+  is $bytes, '[false]', 'encode [!!0]';
+};
+
 subtest 'Faihu roundtrip' => sub {
   my $bytes = j(["\x{10346}"]);
   is b($bytes)->decode('UTF-8'), "[\"\x{10346}\"]", 'encode ["\x{10346}"]';