Dart dynamic attributes using Json

main.dart

void main() {
  var me = Person("Taix", 52, "Montpellier");
  var myTown = City("Montpellier", 277639);
  showAttribute(me, "name");
  showAttribute(myTown, "population");
}

void showAttribute(Jsonifiable object, String attribute) {
  print(object.toJson()[attribute]);
}

class Jsonifiable {
  Map<String, dynamic> toJson() {}
}

class Person implements Jsonifiable {
  final String name;
  final int age;
  final String city;
  Person(this.name, this.age, this.city);
  String toString() => "$name, $age yo, at $city";
  Map<String, dynamic> toJson() => {
        'name': name,
        'age': age,
        'city': city,
      };
}

class City implements Jsonifiable {
  final String name;
  final int population;
  City(this.name, this.population);
  String toString() => "$name w/ $population people";
  Map<String, dynamic> toJson() => {'name': name, 'population': population};
}