[macros] add JsonCodable support for enums

[jimmyff]

Enum's aren't supported by the JsonCodable macro, this is a bit of a shame as string's don't enforce options and classes are still verbose if you have a lot of enum data types.

Couldn't the enums be generated as built enum classes like built_value does?

[jakemac53]

It definitely is possible to add enum support, it just hasn't been implemented. I will move this to the SDK repo and label it as a feature request.

[jimmyff]

Is there a way I could polyfill the solution for now? If the package supported annotations for custom serializer and deserializer (a bit like json_serializable does it with it's JsonKey())?

[jakemac53]

Is there a way I could polyfill the solution for now? If the package supported annotations for custom serializer and deserializer (a bit like json_serializable does it with it's JsonKey())?

The package doesn't support configuration at all because annotations don't work for macros yet.

Note that this package is not ready for production use (the feature is experimental still and will have breaking changes).