toJson method

Implementation

@override
Map<String, dynamic> toJson() {
  final json = super.toJson();
  addWhenNotNull(json, "nftoken_id", nftokenId);
  addWhenNotNull(json, "amount", amount.toJson());
  addWhenNotNull(json, "owner", owner);
  addWhenNotNull(json, "expiration", expiration);
  addWhenNotNull(json, "destination", destination);
  return json;
}