JSON and serialization in Dart

serialize.dart

import 'dart:convert';
import 'dart:core';

void main() {
  var x = {
    'data': [
      {'id': 1, 'attributes': {'name': "R"}}, {'id': 2, 'attributes': {'name': "S"}}
    ]
  };

  Fm.fromJson(x);
}

class Fm {
  final List<Data> data;

  Fm({required this.data});

  factory Fm.fromJson(Map<String, dynamic> parsedJson) {
    var list = parsedJson['data'] as List;
    // print(list.runtimeType);
    List<Data> dataList = list.map((i) => Data.fromJson(i)).toList();
    //print(dataList);
    return Fm(data: dataList);
  }
}
  
class Data {
  final int id;
  final Attributes attributes;

  Data({
    required this.id,
    required this.attributes,
  });

  factory Data.fromJson(Map<String, dynamic> parsedJson) {
    print(parsedJson['id']);
    var attrJson = Attributes.fromJson(parsedJson['attributes']);
    
    return Data(
      id: parsedJson['id'],
      attributes: attrJson,
    );
  }
}
  
class Attributes {
  final String name;

  Attributes({required this.name});


  factory Attributes.fromJson(Map<String, dynamic> parsedJson) {
    print(parsedJson['name']);
    return Attributes(
      name: parsedJson['name'],

    );
  }
}