JAVASCRIPT

nullish coalescing js

The nullish coalescing operator ( ?? ) is a logical operator that returns its right-hand side operand when its left-hand side operand is null or undefined , and otherwise returns its left-hand side operand

nullish coalescing operator in javascript

//nullish coalescing operator in js
Expression:
	Left ?? Right
if left is null or undefined , then Right will be the value

let value = null ?? "Oops.. null or undefined";
console.log(value) //Oops.. null or undefined

value = undefined ?? "Oops.. null or undefined";
console.log(value) //Oops.. null or undefined

value = 25 ?? "Oops.. null or undefined";
console.log(value) // 25

value = "" ?? "Oops.. null or undefined";
console.log(value) // ""

js nullish coalescing ?? vs logical or ||

The OR operator || uses the right value if left is falsy 
(e.g. "" or 0 or false), while the nullish coalescing operator ?? uses
the right value if left is null or undefined.