serializer and deserializer for javascript for externally tagged enum

externally_tagged_enum.js

const gps = {
  type: "gps",
  long: 234,
  lat: 344
};

const kmm = {
  type: "kmm",
  km: 34,
  m: {
    type: "inner",
    i: 3
  },
  section: [1, 2, 3]
};

function serializer(key, value) {
  if (typeof value === "object" && "type" in value) {
    const { type, ...internal } = value;
    return { [type]: internal };
  }
  return value;
}

console.log("stringify");
console.log(JSON.stringify([gps, kmm], serializer));

const str =
  '[{"gps":{"long":234,"lat":344}},{"kmm":{"km":34,"m":{"inner":{"i":3}}}}]';

function deserializer(key, value) {
  // NOTE need to register all the variants here
  if (["gps", "kmm", "inner"].includes(key)) {
    return { type: key, ...value };
  }
  return value;
}

console.log("parse");
console.log(JSON.parse(str, deserializer));

console.log("identity");
console.log(JSON.parse(JSON.stringify([gps, kmm], serializer), deserializer));

console.log([gps, kmm]);