使用对象创建对象时创建默认参数。创造

不知道你为什么不使用 new 关键字,而不是从prototype创建对象,但在这两种情况下,若将默认值设置为对象的prototype,则会在其上获得点。

let Carousel = function(name, dots) {
  this.name = name
  this.dots = dots
}
Carousel.prototype.show = function() {
  console.log(`${this.name} and ${this.dots}`)
}

Carousel.prototype.dots = true;

window.addEventListener('DOMContentLoaded', () => {
  let usps = Object.create(Carousel.prototype, { 
    name: { value: 'element name', writeable: false},
  })
  usps.show() // will show that dots equals true
  let usps2 = Object.create(Carousel.prototype, { 
    name: { value: 'element name', writeable: false},
    dots: { value: false, writeable: false }
  });
  usps2.show(); // will show that dots equals false
})

重要的是,如果你想使用 刚出现的 运算符,则必须修改构造函数,因此如果未设置dots参数,则不会使用 undefined :

let Carousel = function (name, dots) {
  this.name = name;
  if (dots !== undefined) {
    this.dots = dots;
  }
};
Carousel.prototype.show = function () {
  console.log(`${this.name} and ${this.dots}`);
};

Carousel.prototype.dots = true;

window.addEventListener("DOMContentLoaded", () => {
  let usps = new Carousel("element name");
  usps.show();
  let usps2 = new Carousel("element name 2", false);
  usps2.show();
});