Nullish Coalescing in JavaScript

The Nullish Coalescing operator (??) is used to store a default value when a variable is either null or undefined.

Null;

undefined;

let result=value1 ?? value2;

When the first value is null or undefined, then it returns the second value.

If the first value is not null or not undefined, then it returns the first value.

// First Example
let name=null;
let displayName=name ?? 'Guest';
console.log(displayName); // Guest;

// Second Example
let count1 = 0 || 5 ; // 5
let count2 = 0 ?? 5;  // 0

//Third Example
let user= null;
let userName= undefined;
let finalName= user ?? userName ?? "Anonymous";
console.log(finalName); // Anonymous