Flutter/Dart: Converting nested objects

This is sample code for converting json formatted data (e.g. Map<String, dynamic>) into an object where the data/object contain a nested object/class. The conversion includes a nested List of objects and a Map of objects. This might be useful in cases where your data contains a complex hierarchy of data like in a report.

Paste the following code to DartPad to test:

class MyObj {
  final int id;
  final String name;
  final bool active;
  
  MyObj({required this.id, required this.name, required this.active});
  
  factory MyObj.fromJson(Map<String, dynamic> json) {
    return MyObj(
      id: json['id'],
      name: json['name'],
      active: json['active'],
    );
  }
  @override
  String toString() => "<MyObj id: $id, name: $name, active: $active>";
}

class MyMainObj {
  final int id;
  final MyObj object;
  final List<MyObj> objList;
  final Map<String, MyObj> objMap;
  
  MyMainObj({required this.id, required this.object, required this.objList, required this.objMap});
  factory MyMainObj.fromJson(Map<String, dynamic> json) {
    return MyMainObj(
      id: json['id'],
      object: MyObj.fromJson(json['object']),
      objList: (json['objList'] as List).map((i) => MyObj.fromJson(i)).toList(),
      objMap: (json['objMap'] as Map).map((k,v) => MapEntry(k, MyObj.fromJson(v))),
    );
  }
  @override
  String toString() => "id: $id, object: $object, objList: [$objList], objMap: {$objMap}";
}

Map<String, dynamic> data = {
  'id': 1,
  'object': {
    'id': 1,
    'name': "Test Name",
    'active': true,
  },
  'objList': [
    {
    'id': 1,
    'name': "Test Name",
    'active': true,
  },
    {
    'id': 2,
    'name': "Test2 Name",
    'active': false,
  },
  ],
  'objMap': {
    'first': {
    'id': 1,
    'name': "Test Name",
    'active': true,
  },
    'second': {
    'id': 2,
    'name': "Test2 Name",
    'active': false,
  },
  },
};

void main() {
  MyMainObj objData = MyMainObj.fromJson(data);
  print("$objData");
}