How to model class in order to serialize Dart Object (Map) into JSON in Flutter?

Question

I have a Map in Dart that stores events needed to fill up a calendar in my Flutter app: final Map _events = { DateTime(2020, 7, 7): [ {'name': 'Event A', 'isDone': true}, ], DateTime(2020, 7, 11): [ {'name': 'Event A', 'isDone': true} ], DateTime(2020, 7, 9): [ {'name': 'Event A', 'isDone': true}, {'name': 'Event B', 'isDone': true}, ], DateTime(2020, 7, 10): [ {'name': 'Event A', 'isDone': true}, {'name': 'Event B', 'isDone': true}, ], DateTime(2020, 7, 13): [ {'name': 'Event A', 'isDone': true}, {'name': 'Event B', 'isDone': true}, {'name': 'Event C', 'isDone': false}, ], DateTime(2020, 7, 25): [ {'name': 'Event A', 'isDone': true}, {'name': 'Event B', 'isDone': true}, {'name': 'Event C', 'isDone': false}, ], DateTime(2020, 7, 6): [ {'name': 'Event A', 'isDone': false}, ], }; I want to convert this into JSON but I'm not entirely sure how to model the class. Anyone got any ideas?

Christopher Moore · Answer

If you simply want to convert this to a JSON you can use the jsonEncode function and use the toEncodable named parameter to allow your object to be encoded. I made an example here that just cast the keys of your Map to a String so that it can be encoded.
jsonEncode(
  _events,
  toEncodable: (input) {
    return _events.map((key, value) {
      return MapEntry(key.toString(), value);
    });
  }
);

When you want to decode this back to your Map<DateTime, List> you can just do the reverse.
var objectTemp = jsonDecode(
  json,
);
var output = objectTemp.map((key, value) {
  return MapEntry(DateTime.parse(key), value);
})

easeccy · Answer

Create a model class for Event and store the event data in it (name, isDone and date). Then you put them in a List<Event>. You can search on this list for a spesific date and get the according events if any. Then you can make that data class serializable.

How to model class in order to serialize Dart Object (Map) into JSON in Flutter?

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