Exercise 1: Safe Nested Read (optional chaining)

Name: Karmyug Techzone
Address: 2nd Floor, Karuba Tower, 80 Feet Road, Ratlam, Madhya Pradesh, 457001, IN
Telephone: +91-8962241437
Price range: ₹₹

Problem Statement

Function `getCity(user)` banao jo `user.address.city` return kare. Missing ho to "Unknown".

Sample Output:

getCity({address: {city: "Mumbai"}}) => "Mumbai"
getCity({address: {}}) => "Unknown"
getCity(null) => "Unknown"

Solution

const getCity = (user) => user?.address?.city ?? 'Unknown';

Explanation

Overall Goal:

Nested object properties ko safely access karna.
Missing properties handle karna (error avoid).

Single Line Solution:

const getCity = (user) => user?.address?.city ?? 'Unknown';

Part 1: Optional chaining

user?.address?.city
?. → optional chaining operator:
Agar user null/undefined hai → undefined return (error nahi).
Agar user.address null/undefined hai → undefined return (error nahi).
Agar user.address.city exist karta hai → value return.
Without ?.: user.address.city → error if user or address is null.

Part 2: Nullish coalescing

?? 'Unknown'
?? → nullish coalescing operator:
Agar left side null ya undefined hai → right side use karo.
Agar left side value hai → wahi use karo.

Example:

getCity({address: {city: "Mumbai"}}) → "Mumbai".
getCity({address: {}}) → undefined → "Unknown".
getCity(null) → undefined → "Unknown".

Real world:

API responses: data incomplete ho sakta hai.
Form data: optional fields handle karna.
User profiles: nested data access.

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Exercise 2

Exercise 1: Safe Nested Read (optional chaining)

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