dynamicDict_Ocaml.ml

(*
    Handling an object with dynamic keys for sub-objects.
    example:
    {
        static: "hello",
        dynamics: {
            "undetermined1": 2
            "undetermined2": 6
        }
    }

    Where the "undetermined" keys, are unknown at compile time.
    Could be dynamic JS keys generated by user or generally at run time.
*)

type obj = {
  static:   string;
  dynamics: int Js.Dict.t;
}

module Decode = struct
  let obj json =
    Json.Decode.{
      static    = json |> field "static" string;
      dynamics  = json |> field "dynamics" (dict int)
    }
end

module Encode = struct
  let obj c =
    Json.Encode.(
      object_ [
        "static",   c.static   |> string;
        "dynamics", c.dynamics |> dict int
      ]
    )
end

let data = {| {
  "static": "hi",
  "dynamics": { "hello": 5, "random": 8 }
} |}

let decodedData =
  data |> Json.parseOrRaise
       |> Decode.obj

(*
  Will log [ 'hi', { hello: 5, random: 8 } ]
*)
let _ =
    decodedData |> Js.log

(*
  Will log { static: 'hi', dynamics: { hello: 5, random: 8 } }
*)
let encodedDataBack =
    decodedData |> Encode.obj
                |> Js.log