use strict; use warnings;

package JSONTypes {
    use parent 'Type::Library';
    use Type::Utils;
    use Types::Standard qw/ Dict Enum Str Tuple ArrayRef Optional RegexpRef Int /;

    declare JSONType => as Dict[
        method => Enum[qw(xxx yyy)],
        backend => Dict[
            num => Int,
            other => Optional[Str],
            StrMatch[qr/^[a-z0-9]+$/]
        ],
       # following works, but how to check that the array has at least (say) 2 elements  -  {2,}
        clientArr => ArrayRef[
            Dict[ num => Int, ],
        ]
    ];
};

package main {
    use JSON;

    JSONTypes->import(qw/ +JSONType /);

    my $data = from_json q|{
        "method": "xxx",
        "backend": {
            "num": 1,
            "client": "mytest009b"
        },
        "clientArr": [{ "num": "1" }, { "num": "2" }]
    }|;

    my $ret = eval { assert_JSONType( $data ); };
    if ($@) {
        print "ERROR\n$@\n";
    }
    else {
        print "OK\n";
    }

};