Error parsing nested JSON using Built-value

Question

I am trying to use the built-value package to serialize/deserialize data. But I am facing difficulty parsing nested JSON data using the above package. Please help where do I have to make changes, as most of the code is automatically generated by the build runner.

JSON INPUT: 
{
    "Italian": [
        {
            "name": "Item A",
            "price": 297.0,
            "stall": "380b80f4-425a-4916-b8ec-3a2ce0139d07",
        },
        {
            "name": "Item B",
            "price": 72.0,
            "stall": "380b80f4-425a-4916-b8ec-3a2ce0139d07",
        },
    ],
}

abstract class StallMenuItem
    implements Built<StallMenuItem, StallMenuItemBuilder> {
  @BuiltValueField(wireName: 'name')
  String get itemName;
  @BuiltValueField(wireName: 'price')
  num get price;
  @BuiltValueField(wireName: 'stall')
  String get stallId;

  StallMenuItem._();

  factory StallMenuItem([updates(StallMenuItemBuilder b)]) = _$StallMenuItem;
  static Serializer<StallMenuItem> get serializer => _$stallMenuItemSerializer;
}

abstract class StallMenuItemList
    implements Built<StallMenuItemList, StallMenuItemListBuilder> {
  BuiltMap<String, BuiltList<StallMenuItem>> get foodCategoryMap;

  StallMenuItemList._();

  factory StallMenuItemList([updates(StallMenuItemListBuilder b)]) =
      _$StallMenuItemList;
  static Serializer<StallMenuItemList> get serializer =>
      _$stallMenuItemListSerializer;
}

class BuiltValueConvertor extends JsonConverter {
  @override
  Response<BodyType> convertResponse<BodyType, InnerType>(Response response) {
    final Response dynamicResponse = super.convertResponse(response);
    final BodyType customBody = _convertToCustomObject<InnerType>(dynamicResponse.body);
    return dynamicResponse.replace<BodyType>(body: customBody);
  }

  dynamic _convertToCustomObject<InnerType>(dynamic element) {
    if (element is InnerType) return element;
    if (element is List)
      return _deserializeListOf<InnerType>(element);
    else
      return _deserialize<InnerType>(element);
  }

  BuiltList<InnerType> _deserializeListOf<InnerType>(
    List dynamicList,
  ) {
    return BuiltList<InnerType>(
      dynamicList.map((element) => _deserialize<InnerType>(element)),
    );
  }

  InnerType _deserialize<InnerType>(
    Map<String, dynamic> value,
  ) {
    return serializers.deserializeWith<InnerType>(
      serializers.serializerForType(InnerType),
      value,
    );
  }
}

@SerializersFor(const [StallItem, StallMenuItem, StallMenuItemList, BuiltMap])
final Serializers serializers =
    (_$serializers.toBuilder()..addPlugin(StandardJsonPlugin())).build();

I have followed the following tutorials:-https://resocoder.com/2019/07/14/chopper-retrofit-for-flutter-3-converters-built-value-integration/

E/flutter (31674): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: type 'BuiltMapSerializer' is not a subtype of type 'Serializer<BuiltMap<String, BuiltList<StallMenuItem>>>'

Answer 1

abstract class StallMenuItemList
    implements Built<StallMenuItemList, StallMenuItemListBuilder> {
  BuiltList<StallMenuItem> get Italian;

  StallMenuItemList._();

  factory StallMenuItemList([updates(StallMenuItemListBuilder b)]) =
      _$StallMenuItemList;
  static Serializer<StallMenuItemList> get serializer =>
      _$stallMenuItemListSerializer;
}

Kindly use this code.