QnAi로깅

Optional Chaining Operator는 다양한 프로그래밍 언어에서 지원되고 있습니다. 각 언어에서의 사용 예시는 아래와 같습니다.

JavaScript

javascriptCopy code
// ECMAScript 2020 이상에서 지원
const person = {
  name: 'John',
  address: {
    city: 'New York',
    state: 'NY',
    country: 'USA'
  }
};

const zipCode = person?.address?.zipCode ?? 'N/A';
console.log(zipCode); // 'N/A'

TypeScript

typescriptCopy code
interface Person {
  name: string;
  address?: {
    city: string;
    state: string;
    country: string;
  }
}

const person: Person = {
  name: 'John'
};

const zipCode = person?.address?.zipCode ?? 'N/A';
console.log(zipCode); // 'N/A'

Java

javaCopy code
class Person {
  private String name;
  private Address address;

  // 생성자, getter, setter 생략

  public String getZipCode() {
    return address?.getZipCode() ?? "N/A";
  }
}

class Address {
  private String city;
  private String state;
  private String country;
  private String zipCode;

  // 생성자, getter, setter 생략
}

Person person = new Person();
String zipCode = person.getAddress()?.getZipCode() ?? "N/A";
System.out.println(zipCode); // 'N/A'

Python

pythonCopy code
class Person:
  def __init__(self, name, address=None):
    self.name = name
    self.address = address

  def get_zip_code(self):
    return self.address?.get_zip_code() ?? 'N/A'

class Address:
  def __init__(self, city, state, country, zip_code):
    self.city = city
    self.state = state
    self.country = country
    self.zip_code = zip_code

person = Person('John')
zip_code = person.address?.zip_code ?? 'N/A'
print(zip_code) # 'N/A'

Kotlin

kotlinCopy code
data class Person(val name: String, val address: Address?)

data class Address(val city: String, val state: String, val country: String, val zipCode: String?)

fun getZipCode(person: Person): String {
  return person.address?.zipCode ?: "N/A"
}

val person = Person("John", null)
val zipCode = person.address?.zipCode ?: "N/A"
println(zipCode) // 'N/A'