Serializing F# Option types

Question

Consider the F# fragment below:

type MyType = {  
    CrucialProperty: int
    OptionalProperty: string option 
}

let first = { CrucialProperty = 500; Optio         


        

Answer 1

The FSharp.JsonSkippable library allows you to control in a simple and strongly typed manner whether to include a given property when serializing (and determine whether a property was included when deserializing), and moreover, to control/determine exclusion separately of nullability. (Full disclosure: I'm the author of the library.)

Answer 2

I would recommend FifteenBelow's converters which work with JSON.NET but provide serialization F# types https://github.com/15below/FifteenBelow.Json (apparently moved to https://github.com/kolektiv/FifteenBelow.Json).

From their usage section:

let converters =
    [ OptionConverter () :> JsonConverter
      TupleConverter () :> JsonConverter
      ListConverter () :> JsonConverter
      MapConverter () :> JsonConverter
      BoxedMapConverter () :> JsonConverter
      UnionConverter () :> JsonConverter ] |> List.toArray :> IList<JsonConverter>

let settings =
    JsonSerializerSettings (
        ContractResolver = CamelCasePropertyNamesContractResolver (), 
        Converters = converters,
        Formatting = Formatting.Indented,
        NullValueHandling = NullValueHandling.Ignore)

Specifically what you're looking for is the the NullValueHandling = NullValueHandling.Ignore bit.