I'm deserializing a `Date?` from a `String?` using...

# serialization

[Russell Cullen]

I'm deserializing a Date? from a String? using a custom KSerializer<Date> and it's working great, until the 3rd party API I'm using sends an empty string instead of null as expected. Is there a way to map this empty case to a null Date instead of a dummy-Date? It seems something like KSerializer<Date?> is not supported, is that correct?

[Fudge]

To get a nullable serializer of something do .nullable like .list

[Fudge]

(Actually I’m not sure if this was pushed yet, if not you can wrap your date serializer into a NullableSerializer instead)

[Russell Cullen]

Well the problem isn't just nullability, nulls map to each other fine. But during deserialization I want to map an empty string to a null date, but KSerializer<Date> does not allow null return types. (And KSerializer<Date?> does not match the Date? types on my class for some reason)

How can I use .nullable in an annotation? I assumed this was used under the hood already for me since my Date types are nullable.

At the end, I would like a deserializer that does the following:
String? -> Date? where null or "" maps to null: Date?

[Kroppeb]

if you want to decode a nullable element the serializer calls the decodeNullableElement of the compositedecoder which will most likely call decodeNotNullMark() on the decoder which will return false if the next value is null.

[Kroppeb]

So unless you have custom decoder I don't see how you'd fix it.

[Russell Cullen]

Yeah that's what I figured, thanks! I have a workaround right now and just pick a reasonable default.