嵌套对象的快速帮助

let person = {
    name: "John",
    age: 30,
    address: {
        street: "123 Main St",
        city: "Anytown",
        zip: "12345"
    }
};

console.log(person.address.city); // 输出: Anytown
console.log(person['address']['city']); // 输出: Anytown

function traverse(obj) {
    for (let key in obj) {
        if (obj.hasOwnProperty(key)) {
            console.log(key + ": " + obj[key]);
            if (typeof obj[key] === 'object') {
                traverse(obj[key]);
            }
        }
    }
}

traverse(person);

let city = person.address ? person.address.city : 'Unknown';
console.log(city); // 输出: Anytown 或 Unknown

let deepCopy = JSON.parse(JSON.stringify(person));
// 或者使用Lodash
// let deepCopy = _.cloneDeep(person);