melange-json-test

app.ml

module Color = struct
  type t = Red | Green | Blue

  let to_string = function Red -> "red" | Green -> "green" | Blue -> "blue"

  let of_json json =
    Json.Decode.(
      field "kind" string json |> function
      | "red" -> Red
      | "green" -> Green
      | "blue" -> Blue
      | _ -> failwith "Invalid color")
  ;;

  let to_json = function
    | Red -> Json.Encode.(object_ [ ("kind", string "red") ])
    | Green -> Json.Encode.(object_ [ ("kind", string "green") ])
    | Blue -> Json.Encode.(object_ [ ("kind", string "blue") ])
  ;;
end

let main () =
  let json = Json.Encode.(object_ [ ("kind", string "red") ]) in
  let color = Color.of_json json in
  Js.log (Color.to_string color)
;;

output.mjs

// Generated by Melange

import * as Json__Json_decode from "melange-json/Json_decode.mjs";
import * as Json__Json_encode from "melange-json/Json_encode.mjs";
import * as Stdlib from "melange/stdlib.mjs";

function to_string(param) {
  switch (param) {
    case /* Red */ 0:
      return "red";
    case /* Green */ 1:
      return "green";
    case /* Blue */ 2:
      return "blue";
  }
}

function of_json(json) {
  var param = Json__Json_decode.field("kind", Json__Json_decode.string, json);
  switch (param) {
    case "blue":
      return /* Blue */ 2;
    case "green":
      return /* Green */ 1;
    case "red":
      return /* Red */ 0;
    default:
      return Stdlib.failwith("Invalid color");
  }
}

function to_json(param) {
  switch (param) {
    case /* Red */ 0:
      return Json__Json_encode.object_({
        hd: ["kind", "red"],
        tl: /* [] */ 0,
      });
    case /* Green */ 1:
      return Json__Json_encode.object_({
        hd: ["kind", "green"],
        tl: /* [] */ 0,
      });
    case /* Blue */ 2:
      return Json__Json_encode.object_({
        hd: ["kind", "blue"],
        tl: /* [] */ 0,
      });
  }
}

var Color = {
  to_string: to_string,
  of_json: of_json,
  to_json: to_json,
};

function main(param) {
  var json = Json__Json_encode.object_({
    hd: ["kind", "red"],
    tl: /* [] */ 0,
  });
  var color = of_json(json);
  console.log(to_string(color));
}

export { Color, main };
/* No side effect */