SYNOPSIS

     # in function metadata
     result_postfilter => {
         re   => 'str',    # convert regex object to string
         date => 'epoch',  # convert date object to an integer Unix time
         code => 'str',    # convert subroutine to string literal 'CODE'
     }

DESCRIPTION

    NOTE: The use of this property is now deprecated. Generating filtering
    code for each function is quite wasteful when there are hundreds or
    more functions that are wrapped. Instead, see Data::Clean::JSON.

    This property specifies postfilters for function result. Currently the
    focus of this property is converting values that are unsafe when
    exporting to JSON/YAML.

    Value: a hash containing instruction of how to filter. Known keys:

      * re (filter regex object)

      With filter values: str (stringify it).

      * date (date object, such as DateTime in Perl)

      With filter values: epoch (convert to Unix epoch time).

      * code (subroutine)

      With filter values: str (convert to string literal CODE).

    More sophisticated filtering rules might be specified in the future.

    Filtering using generated code can be faster since the code will use
    for() loop and inline conversion instead of callback for each data item
    (higher subroutine call overhead).

NOTES

    Another alternative is using the encoder's facility, for example the
    JSON module can convert blessed object:

     use JSON 2;
     my $encoder = JSON->new->convert_blessed;
     {
         local *DateTime::TO_JSON = sub { $_[0]->ymd };
         print $encoder->encode($doc);
     }

    But this currently can't convert coderefs. JSON also can't handle
    circular references, which neither this wrapper property nor the above
    way can work around.

SEE ALSO

    Perinci