提取超类

refactorgram

class Department {
  get totalAnnualCost() {...}
  get name() {...}
  get headCount() {...}
}

class Employee {
  get annualCost() {...}
  get name() {...}
  get id() {...}
}

class Party {
  get name() {...}
  get annualCost() {...}
}

class Department extends Party {
  get annualCost() {...}
  get headCount() {...}
}

class Employee extends Party {
  get annualCost() {...}
  get id() {...}
}