从继承自父对象的方法获取对象的子类型

class Animal {
  // 父类型
  constructor(name) {
    this.name = name;
  }
}

class Dog extends Animal {
  // 子类型
  constructor(name, breed) {
    super(name);
    this.breed = breed;
  }
}

const myDog = new Dog("Max", "Labrador");

console.log(myDog instanceof Dog); // true
console.log(myDog instanceof Animal); // true

class Animal {
  // 父类型
  constructor(name) {
    this.name = name;
  }
}

class Dog extends Animal {
  // 子类型
  constructor(name, breed) {
    super(name);
    this.breed = breed;
  }
}

const myDog = new Dog("Max", "Labrador");

console.log(myDog.constructor === Dog); // true
console.log(myDog.constructor === Animal); // false