js中的object数据类型

// 字面量方式
let person = {
    name: "Alice",
    age: 25,
    greet: function() {
        console.log("Hello, my name is " + this.name);
    }
};

// 构造函数方式
function Person(name, age) {
    this.name = name;
    this.age = age;
    this.greet = function() {
        console.log("Hello, my name is " + this.name);
    };
}

let bob = new Person("Bob", 30);

console.log(person.name); // 输出: Alice
console.log(person['age']); // 输出: 25

person.greet(); // 输出: Hello, my name is Alice

for (let key in person) {
    console.log(key + ": " + person[key]);
}

console.log(person.__proto__ === Object.prototype); // 输出: true

let sym = Symbol('key');
person[sym] = "unique value";

function deepCopy(obj) {
    return JSON.parse(JSON.stringify(obj));
}

class Animal {
    constructor(name) {
        this.name = name;
    }
    speak() {
        console.log(this.name + ' makes a noise.');
    }
}

class Dog extends Animal {
    speak() {
        console.log(this.name + ' barks.');
    }
}

let dog = new Dog('Rex');
dog.speak(); // 输出: Rex barks.