Example of Flutter/Dart Dynamic JSON Key Parsing

main.dart

const rawData = {
  'status': 'Success',
  'data': {
    '2022-10-1': true,
    '2022-10-2': false,
    '2022-10-3': true,
    '2022-10-4': false,
  }
};

void main() {
  final jsonParseResult = Model1.fromJson(rawData);
  
  print('STATUS: ${jsonParseResult.status}');
  print('DATA:');
  for (final item in jsonParseResult.data){
    print('Model2(field1: ${item.field1}, field2: ${item.field2})');
  }
  
}

class Model1 {
  const Model1({
    required this.data,
    required this.status,
  });

  final List<Model2> data;
  final String status;

  factory Model1.fromJson(Map<String, dynamic> json) {
    final _data = <Model2>[];

    if (json['data'] != null && json['data'] is Map) {
      for (final element in (json['data'] as Map).entries) {
        _data.add(Model2.fromJson(element as MapEntry<String, dynamic>));
      }
    }

    return Model1(
      data: _data,
      status: json['status'] ?? 'failure',
    );
  }
}

class Model2 {
  const Model2({
    required this.field1,
    required this.field2,
  });
  
  final String field1;
  final bool field2;

  factory Model2.fromJson(MapEntry<String, dynamic> json) {
    return Model2(
      field1: json.key,
      field2: json.value,
    );
  }
}