问题

我正在学习一个教程，但遇到了问题。在ShelterDog类中调用方法'bark（）'，在浏览器控制台中返回 * <empty string> *，而不是预期的"WOOF WOOF!!!"
编号

// Dog.ts
export default class Dog {
    constructor(
        public name: string,
        public breed: string,
        public age: number
    ) {}
    bark():void {
        console.log("WOOF WOOF!!!");
    }
}

// ShelterDog.ts

import Dog from "./Dog.js";

export default class ShelterDog extends Dog {
    constructor(
        name: string,
        breed: string,
        age: number,
        public shelter: string
    ) {
        super(name, breed, age);
        this.shelter = shelter
    }
}

// index.ts

import Dog from "./Dog.js"
import ShelterDog from "./ShelterDog.js"

const elton = new Dog("Elton", "Aussie", 0.5)
elton.bark()

const benton = new ShelterDog("Benton","Madman",99,"Chaos Refuge")
benton.bark()