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JS constructors

发布时间 2023-05-25 15:32:35作者: saaspeter

我们可以这样create一个object：

const person1 = {
  name: "Chris",
  introduceSelf() {
    console.log(`Hi! I'm ${this.name}.`);
  },
};

但是当我们需要创建多个对象的时候，每次都要重复同样的code，这时候我们可以用构造函数

A better way is to use a constructor. A constructor is just a function called using the new keyword. When you call a constructor, it will:

  • create a new object
  • bind this to the new object, so you can refer to this in your constructor code
  • run the code in the constructor
  • return the new object.

Constructors, by convention, start with a capital letter and are named for the type of object they create. So we could rewrite our example like this:

function Person(name) {
  this.name = name;
  this.introduceSelf = function () {
    console.log(`Hi! I'm ${this.name}.`);
  };
}

To call Person() as a constructor, we use new:

const salva = new Person("Salva");
salva.name;
salva.introduceSelf();
// "Hi! I'm Salva."

const frankie = new Person("Frankie");
frankie.name;
frankie.introduceSelf();
// "Hi! I'm Frankie."