Result Type Dart

main.dart

void main() {
  final item = {'1': 'Apple'};
  final operationSuccessed = Result.success(item);
  final operationFailed = Result.error(Failure('Cannot catch data'));

  print(operationSuccessed.result);
  print(operationFailed.error);
}

class Result<Success, Error extends Failure> {
  final Error error;
  final Success result;

  bool get isSuccess => error == null;

  const Result.success(this.result) : error = null;

  const Result.error(this.error) : result = null;
}


class Failure {
  final String message;

  const Failure(this.message);

  @override
  String toString() => message;
}

https://dartpad.dev/1550abe4f921188ebfa005db5f0604df

@minkin nice one but I have question in real world scenario
Lets say I have a function like belwo

  Result<String, Error> getData() {
    
    return Result.success("Hello");
  }
  
  var result = getData();

result will be of a Result type ... how can I determine if it was an error or success without using the boolean you have