Skip unparsable Collection values

[nrobi144]

Given a JSONArray, where certain items can't be parsed, what's the best way to skip/filter only those elements, instead of failing to parse the whole JSONArray.

Example:

@JsonSerializable
class MyWrapperResponse(List<SomeType> object);

where parsing certain SomeTypes will fail, but the app would still like to show the other items.

Thinking of a custom converter:

class ListSkipConverter<T extends JsonSerializable> implements JsonConverter<List<T>, Map<String, dynamic>> {
  const ListSkipConverter({required this.key});

  final String key;

  @override
  List<T> fromJson(Map<String, dynamic> json) => (json[key] as List<dynamic>)
      .map((e) {
        try {
          return e.fromJson(e as Map<String, dynamic>) as T;
        } catch (e) {
          return null;
        }
      })
      .whereType<T>()
      .toList();

  @override
  Map<String, dynamic> toJson(List<T> object) => {key: object.map((e) => e.toJson()).toList()};
}

which unfortunately doesn't work as these converters are only post processors 🤔