main.dart

typedef DataItemTransformer = Object Function(Map<String, dynamic> item);

class HasNext<T extends Object> {
  const HasNext({
    this.hasNext,
    this.data,
  });

  HasNext.fromMap(
      Map<String, dynamic> map, DataItemTransformer dataItemTransformer)
      : hasNext = map['has_next'],
        data = List.from(map['data'])
            .fold<List<T>>(<T>[], _buildItemsFilter<T>(dataItemTransformer))
            .cast<T>()
            .toList();

  final bool hasNext;
  final List<T> data;

  static List<T> Function(List<T> acc, Map<String, dynamic> item)
      _buildItemsFilter<T extends Object>(
              DataItemTransformer dataItemTransformer) =>
          (List<T> acc, dynamic item) {
            try {
              acc.add(dataItemTransformer(item));
            } catch (_) {}
            return acc;
          };
}

void main() {
  const response = {
    "has_next": false,
    "data": [
      {
        "name": "Эксперт",
        "periodicity": "weekly",
        "is_collected": false,
        "latest_issue": {
          "timestamp": 1563148800,
          "cover":
              "https://lib.public.ru/media/v2/issues/14489/pages/1.jpg/resize/120x-?1563142993",
          "id": 14489
        },
        "type": "magazine",
        "id": 2
      },
      {
        "name": "Forbes",
        "periodicity": "monthly",
        "is_collected": false,
        "latest_issue": {
          "timestamp": 1561939200,
          "cover":
              "https://lib.public.ru/media/v2/issues/14100/pages/1.jpg/resize/120x-?1562676207",
          "id": 14100
        },
        "type": "magazine",
        "id": 45
      }
    ]
  };

  final h = HasNext.fromMap(response, (x) => x);

  print(h);
}