dart json encoder/decoder

json_encoder_decoder.dart

///
/// ## reference
///
/// [JsonEncoder](https://api.dartlang.org/stable/1.24.2/dart-convert/JsonEncoder/JsonEncoder.html)
/// [JsonDecoder](https://api.dartlang.org/stable/1.24.2/dart-convert/JsonDecoder/JsonDecoder.html)
///
/// [Vloz/JSON_Encode_Decode.dart](https://gist.github.com/Vloz/11363954)
/// [better reviver API for JsonDecoder #29750](https://github.com/dart-lang/sdk/issues/29750)
///
///

import "dart:convert";
import "dart:mirrors";

class JsonSerializable {
  fromRaw(var raw) {}
  toJson() => {};
}

class Foo1 implements JsonSerializable {
  String name;
  fromRaw(var raw) {
    this.name = raw['name'];
  }

  toJson() => {'name': this.name, '__type__': 'Foo1'};
}

class Foo2 implements JsonSerializable {
  String name;
  fromRaw(var raw) {
    this.name = raw['name'];
  }

  toJson() => {'name': this.name, '__type__': 'Foo2'};
}

class Foo3 implements JsonSerializable {
  String name;
  fromRaw(var raw) {
    this.name = raw['name'];
  }

  toJson() => {'name': this.name, '__type__': 'Foo3'};
}

Map toEncodable(var obj) {
  if (obj is JsonSerializable) {
    return obj.toJson();
  } else {
    return obj;
  }
}

Object reviver(var key, var value) {
  if (value is Map) {
    var type = value['__type__'];
    if (type != null) {
      LibraryMirror lm = currentMirrorSystem().findLibrary(new Symbol(''));
      ClassMirror classMirror = lm.declarations[new Symbol(type)];
      InstanceMirror insMirror = classMirror.newInstance(new Symbol(''), []);
      insMirror.invoke(#fromRaw, [value]);
      return insMirror.reflectee;
    }
  }
  return value;
}

main() {
  var jsonEncoder = new JsonEncoder(toEncodable);
  var jsonDeocder = new JsonDecoder(reviver);

  var foo1 = new Foo1()..name = 'Foo01';
  var foo2 = new Foo2()..name = 'Foo02';
  var foo3 = new Foo3()..name = 'Foo03';

  var originalData = [
    {'foo1': foo1},
    {'foo2': foo2},
    {'foo3': foo3},
  ];

  var jsonStr = jsonEncoder.convert(originalData);
  print('jsonStr: $jsonStr');

  var restoreData = jsonDeocder.convert(jsonStr);
  print(originalData);
  print(restoreData);
}