strategy2.dart

void main(){
  final Employee emp1 = Employee(EmployeeTypes.engineer);
  
  emp1.work();
}

class Employee {
  late final EmployeeStrategy _strategy;
  Employee(EmployeeTypes type){
    _setStrategy(type);
  }
  
  void _setStrategy(EmployeeTypes type) => _strategy = EmployeeStrategy.init(type);
  EmployeeStrategy get employee => _strategy;
  
  void work(){
    employee.work();
  }
}

// Strategy/State class
abstract class EmployeeStrategy {
  
  factory EmployeeStrategy.init(EmployeeTypes type){
    switch(type){
      case EmployeeTypes.salesman:
        return Salesman();
      case EmployeeTypes.engineer:
      default:
       return Engineer();
    }
  }
  
  EmployeeTypes get type;
  
  void work();
}

class Salesman implements EmployeeStrategy {
  @override
  EmployeeTypes get type => EmployeeTypes.salesman;

  @override
  void work() {
    print('Making Sales');
  }
}

class Engineer implements EmployeeStrategy {
  @override
  EmployeeTypes get type => EmployeeTypes.engineer;

  @override
  void work() {
    print('Architecting technology');
  }
}

enum EmployeeTypes {
  salesman,
  engineer,
}