JS对象创建怎么实现_JS对象创建与属性方法使用教程

let person = {
  name: "张三",
  age: 25,
  sayHello: function() {
    console.log("你好，我是" + this.name);
  }
};

person.sayHello(); // 输出：你好，我是张三
console.log(person.age); // 输出：25

function Person(name, age) {
  this.name = name;
  this.age = age;
  this.sayHello = function() {
    console.log("你好，我是" + this.name);
  };
}

let p1 = new Person("李四", 30);
let p2 = new Person("王五", 28);

p1.sayHello(); // 输出：你好，我是李四
p2.sayHello(); // 输出：你好，我是王五

function Animal(type) {
  this.type = type;
}

Animal.prototype.speak = function() {
  console.log(this.type + " 在叫");
};

let dog = new Animal("狗");
let cat = new Animal("猫");

dog.speak(); // 输出：狗 在叫
cat.speak(); // 输出：猫 在叫

class Car {
  constructor(brand, year) {
    this.brand = brand;
    this.year = year;
  }

  start() {
    console.log(this.brand + " 启动了");
  }
}

let myCar = new Car("丰田", 2020);
myCar.start(); // 输出：丰田 启动了

let user = {};

user.username = "admin";
user.login = function() {
  console.log(this.username + " 登录成功");
};

user.login(); // 输出：admin 登录成功

let key = "email";
user[key] = "admin@example.com";
console.log(user.email); // 输出：admin@example.com

delete user.email;
console.log(user.email); // 输出：undefined