Function json_kind_of 

pub fn json_kind_of(b: BaseType) -> JsonKind

The JSON kind a base type wires as. Same mapping as the ts_base_for_serialisation it replaces: Int/Float/Duration/Instant → Number (all four erase to a TS number), String/Bytes → String (a Bytes wires as a base64 string, ADR 0142 D5), Bool → Boolean.