js object 所有属性

// 创建一个对象
let person = {
    firstName: "John",
    lastName: "Doe",
    age: 30,
    fullName: function() {
        return this.firstName + " " + this.lastName;
    }
};

// 访问对象属性
console.log(person.firstName); // 输出: John

// 调用对象方法
console.log(person.fullName()); // 输出: John Doe

// 添加新属性
person.email = "john.doe@example.com";
console.log(person.email); // 输出: john.doe@example.com

// 删除属性
delete person.age;
console.log(person.age); // 输出: undefined

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

if ('email' in person) {
    console.log('Email exists');
}

let copyPerson = Object.assign({}, person);
// 或者使用展开运算符
let copyPerson2 = {...person};