js 声明一个对象

let person = {
  name: "John",
  age: 30,
  sayHello: function () {
    console.log("Hello!");
  }
};

function Person(name, age) {
  this.name = name;
  this.age = age;
  this.sayHello = function () {
    console.log("Hello!");
  };
}

let person = new Person("John", 30);

let proto = {
  sayHello: function () {
    console.log("Hello!");
  }
};

let person = Object.create(proto);
person.name = "John";
person.age = 30;