从嵌套对象javascript返回特定值

const data = {
  person: {
    name: "John",
    age: 30,
    address: {
      city: "New York",
      country: "USA"
    }
  }
};

const city = data.person.address.city;
console.log(city); // 输出：New York

const { city } = data.person.address;
console.log(city); // 输出：New York

const data = {
  person: {
    name: "John",
    age: 30,
    address: {
      city: "New York",
      country: "USA"
    }
  }
};

// 判断嵌套对象中的属性是否存在，并根据条件获取值
const city = data.person.address ? data.person.address.city : "Unknown";
console.log(city); // 输出：New York（因为属性存在）

const phoneNumber = data.person.contact ? data.person.contact.phone : "Unknown";
console.log(phoneNumber); // 输出：Unknown（因为属性不存在）

function getValue(obj, keys) {
  const [currentKey, ...restKeys] = keys;
  
  if (obj.hasOwnProperty(currentKey)) {
    if (restKeys.length === 0) {
      return obj[currentKey];
    } else {
      return getValue(obj[currentKey], restKeys);
    }
  } else {
    return "Unknown";
  }
}

const data = {
  person: {
    name: "John",
    age: 30,
    address: {
      city: "New York",
      country: "USA"
    }
  }
};

const city = getValue(data, ["person", "address", "city"]);
console.log(city); // 输出：New York

const phoneNumber = getValue(data, ["person", "contact", "phone"]);
console.log(phoneNumber); // 输出：Unknown