setPrototypeOf()方法的语法为：
Object.setPrototypeOf(obj, prototype) setPrototypeOf()方法是一种静态方法，使用Object类名称进行调用。
setPrototypeOf()参数
setPrototypeOf()方法采用：
- obj-要设置其原型的对象。
- prototype-对象的新原型(对象或null)。
从setPrototypeOf()返回值
- 返回指定的对象。
注意：在每个浏览器和JavaScript引擎中，更改对象的[[Prototype]]当前都是非常缓慢的操作。
示例1：使用Object.setPrototypeOf()
let Animal = {
makeSound() {
console.log(`${this.name}, ${this.sound}!`);
},
};
// defining new Dog object
function Dog(name) {
this.name = name;
this.sound = "bark";
// setting prototype to Animal
Object.setPrototypeOf(this, Animal);
}
dog1 = new Dog("Marcus");
dog1.makeSound(); // Marcus, bark!输出
Marcus, bark!示例2：使用Object.setPrototypeOf()
let Animal = {
makeSound() {
console.log(`${this.name}, ${this.sound}!`);
},
};
// defining object
class Dog {
constructor(name, age) {
this.name = name;
this.sound = "bark";
}
introduce() {
console.log(`I'm ${this.name}. I am ${this.age} years old.`);
}
}
// Here Dog.prototype is passed as it is an object, while Dog is not an object
Object.setPrototypeOf(Dog.prototype, Animal);
dog1 = new Dog("Marcus", 3);
console.log(dog1);
dog1.makeSound(); // Marcus, bark!输出
name: "Marcus"
sound: "bark"
__proto__:
constructor: class Dog
introduce: ƒ introduce()
__proto__:
makeSound: ƒ makeSound()
__proto__: Object
Marcus, bark!推荐阅读： Javascript对象isPrototypeOf()