Summary

Bugungi mavzuyimiz top Javascript interview savollarda tushadigan Optional Chaining ( ?. ) operatori haqida bo’ladi. Optinal Chaining juda ko’p joylarda ishlatiladi va eng kerakli operatorlardan biri xisoblanadi qani u nima ekan boshladik!.

Category

JavaScript

Optional Chaining

Javascript interview

Interview

JavaScript operator

Cover

Slug

javascripda-optional-chaining

Date

‣

author

Published

Published

javascriptCopy code
let user = {
  name: 'Anvarbek',
  address: {
    city: 'Toshkent',
    street: 'Navoiy ko‘chasi'
  }
};

console.log(user.address.city); // Toshkent

let user = {
  name: 'Anvar'
};

console.log(user.address.city); // TypeError: Cannot read property 'city' of undefined

if (user.address && user.address.city) {
  console.log(user.address.city);
}

console.log(user.address?.city); // undefined (Xatolik kelib chiqmaydi)

1. Obyekt maydonlariga kirishda:

let user = {};
console.log(user.profile?.age); // undefined

1. Array elementlariga kirishda:

let users = null;
console.log(users?.[0]); // undefined

1. Funksiyalarni chaqirishda:

let user = {
  sayHello: function() {
    return "Salom!";
  }
};

console.log(user.sayHello?.()); // Salom!
console.log(user.sayGoodbye?.()); // undefined, xatolik yo'q