toJson method Null safety

Map<String, dynamic> toJson()

Implementation

Map<String, dynamic> toJson() => {
      "year": year,
      "month": month,
      "day": day,
      "city": city?.toJson(),
      "isSubscribed": isSubscribed,
      "minAge": minAge,
      "id": id,
      "firstName": firstName,
      "lastName": lastName,
      "mobile": mobile,
      "email": email,
      "isActive": isActive,
      "zoneID": zoneId,
      "gender": gender,
    };