Dart : Enums | Enumerations

Enum :

• An enum is a special type that represents a fixed number of constant values.

• An enum is declared using the keyword enum followed by the enum’s name.

enum Color {
  red,
  green,
  blue,
}

extension ColorExtension on Color {
  String get displayName {
    switch (this) {
      case Color.red:
        return 'Red';
      case Color.green:
        return 'Green';
      case Color.blue:
        return 'Blue';
      default:
        throw ArgumentError('Unknown color: $this');
    }
  }

  // You can define other methods or properties here
}

void main() {
  print(Color.red.displayName); // Output: Red
}

Enumerations :

• Enumerated types (also known as enumerations or enums) are primarily used to define named constant values.

• The enum keyword is used to define an enumeration type in Dart.

• The use case of enumeration is to store finite data members under the same type definition.

enum Vehicle implements Comparable<Vehicle> {
  car(tires: 4, passengers: 5, carbonPerKilometer: 400),
  bus(tires: 6, passengers: 50, carbonPerKilometer: 800),
  bicycle(tires: 2, passengers: 1, carbonPerKilometer: 0);

  const Vehicle({
    required this.tires,
    required this.passengers,
    required this.carbonPerKilometer,
  });

  final int tires;
  final int passengers;
  final int carbonPerKilometer;

  int get carbonFootprint => (carbonPerKilometer / passengers).round();

  bool get isTwoWheeled => this == Vehicle.bicycle;

  @override
  int compareTo(Vehicle other) => carbonFootprint - other.carbonFootprint;
}

void main() {

  var vehicleList = [Vehicle.bus, Vehicle.car, Vehicle.bicycle];
  print('Before sorting:\n${vehicleList.join('\n')}\n');

}