🍎객체 지향 프로그래밍 (7) Super Keyword

class Person {
  constructor(name, first, second) {
    this.name = name
    this.first = first
    this.second = second
  }
  sum() {
    return this.first + this.second
  }
}

class PersonPlus extends Person {
  avg() {
    return (this.first + this.second) / 2
  }
}

let kim = new PersonPlus('kim', 10, 20, 30)

class Person {
  constructor(name, first, second) {
    this.name = name
    this.first = first
    this.second = second
  }
  sum() {
    return this.first + this.second
  }
}

class PersonPlus extends Person {
  constructor(name, first, second, third) {
    this.name = name
    this.first = first
    this.second = second
    this.third = third
  }
  sum() {
    return this.first + this.second + this.third
  }
  avg() {
    return (this.first + this.second + this.third) / 3
  }
}

class Person {
  constructor(name, first, second) {
    this.name = name
    this.first = first
    this.second = second
  }
  sum() {
    return this.first + this.second
  }
}

class PersonPlus extends Person {
  constructor(name, first, second, third) {
    // this.name = name
    // this.first = first
    // this.second = second
    // 부모의 기능과 중복되는 기능을 제거하고,
    super(name, first, second) // super() 를 대신 넣어준다.
    this.third = third
  }
  sum() {
    return this.first + this.second + this.third
  }
  avg() {
    return (this.first + this.second + this.third) / 3
  }
}

return this.first + this.second + this.third
return this.first + this.second + this.third
return this.first + this.second + this.third
return this.first + this.second + this.third
return this.first + this.second + this.third

class Person {
  constructor(name, first, second) {
    this.name = name
    this.first = first
    this.second = second
  }
  sum() {
    return this.first + this.second
  }
}

class PersonPlus extends Person {
  constructor(name, first, second, third) {
    // this.name = name
    // this.first = first
    // this.second = second
    // 부모의 기능과 중복되는 기능을 제거하고,
    super(name, first, second) // super() 를 대신 넣어준다.
    this.third = third
  }
  sum() {
    // return this.first + this.second + this.third
    return super.sum() + this.third
  }
  avg() {
    // return (this.first + this.second + this.third) / 3
    return (super.sum() + this.third) / 3
  }
}

let teddy = new Person('teddy', 10, 20)

teddy
Person {name: "teddy", first: 10, second: 20}
teddy.sum()
30

let sunny = new PersonPlus('sunny', 10, 20, 30)

sunny
PersonPlus {name: "sunny", first: 10, second: 20, third: 30}
sunny.sum()
60
sunny.avg()
20