Support Belt.Map.t

[ryb73]

No description provided.

[nickretallack]

Yes, please add this. It's a pretty basic piece of functionality.

Here's how I'm working around it right now for Belt.Map.String.t:

let mapToJson = (encode: 'a => Js.Json.t, map: Belt.Map.String.t('a)) =>
  Json.Encode.object_(
    Belt.List.map(Belt.Map.String.toList(map), ((key, item)) =>
      (key, encode(item))
    ),
  );

let deccoMapFromJson = (decode, json) => {
  switch (Decco.dictFromJson(decode, json)) {
  | Belt.Result.Ok(result) =>
    Ok(Belt.Map.String.fromArray(Js.Dict.entries(result)))
  | Belt.Result.Error(error) => Error(error)
  };
};

[@decco]
type StringMap('a) =
  [@decco.codec (mapToJson, deccoMapFromJson)]
  Belt.Map.String.t('a);

The mapToJson I already had lying around and it happens to work. The other one I had to write custom because decco returns result types while Json.Encode raises exceptions.

[Pet3ris]

Same idea, applied to integers.

let intMapToJson = (encode: 'a => Js.Json.t, map: Belt.Map.Int.t('a)) =>
  Json.Encode.object_(
    Belt.List.map(Belt.Map.Int.toList(map), ((key, item)) =>
      (string_of_int(key), encode(item))
    ),
  );

let deccoIntMapFromJson = (decode, json) => {
  switch (Decco.dictFromJson(decode, json)) {
  | Belt.Result.Ok(result) =>
    Ok(Js.Dict.entries(result)
    -> Belt.Array.map(((key, value)) => (int_of_string(key), value))
    -> Belt.Map.Int.fromArray)
  | Belt.Result.Error(error) => Error(error)
  };
};

[@decco]
type intMap('a) =
  [@decco.codec (intMapToJson, deccoIntMapFromJson)] Belt.Map.Int.t('a);