Cartype.js

class Sedan extends Car {
  constructor(name) {
    super()
    this.name = name
  }
  
  operate(visitor=CarVisitor) {
    visitor.accelerate(this)
  }
}

class Hatchback extends Car {
  constructor(name) {
    super()
    this.name = name
  }
  
  operate(visitor=CarVisitor) {
    visitor.brake(this)
  }
}