-spec encode(atom(),
             module(),
             spectra:sp_type_reference(),
             dynamic(),
             spectra:sp_type(),
             term(),
             spectra:sp_config()) ->
                spectra:codec_encode_result().

Built-in codec for calendar:datetime() and calendar:date().

Serialises to ISO 8601 strings and parses them back:

• calendar:datetime() ↔ "YYYY-MM-DDTHH:MM:SSZ" (e.g. "2024-01-15T10:30:00Z")
• calendar:date() ↔ "YYYY-MM-DD" (e.g. "2024-01-15")

calendar:datetime() carries no timezone information — values are treated as UTC. Encoding always appends Z; decoding requires the Z suffix and rejects any other offset (e.g. +01:00).

If you need full timezone support, use a dedicated datetime library (e.g. qdate or calendar_extended) and implement a custom spectra_codec behaviour for it.

Registering

Not active by default. Add to the application environment:

{spectra, [
    {codecs, #{
        {calendar, {type, datetime, 0}} => spectra_calendar_codec,
        {calendar, {type, date, 0}} => spectra_calendar_codec
    }}
]}

Register only the types you use — registering both is fine, and each is independent.

Example

-type meeting() :: #{title => binary(), at => calendar:datetime()}.

DT = {{2024, 1, 15}, {10, 30, 0}},
{ok, Encoded} = spectra:encode(json, my_module, meeting, #{title => <<"Standup">>, at => DT}).
%% => {ok, <<"{\"title\":\"Standup\",\"at\":\"2024-01-15T10:30:00Z\"}">>}

{ok, Decoded} = spectra:decode(json, my_module, meeting, Encoded).
%% => {ok, #{title => <<"Standup">>, at => {{2024,1,15},{10,30,0}}}}