JavaScript Other Operators

1. Ternary Operator (? :)

A shortcut for if...else statements.

let age = 18;
let message = (age >= 18) ? "Adult" : "Minor";
console.log(message); // Output: Adult

Syntax:

condition ? valueIfTrue : valueIfFalse;

2. typeof Operator

Returns the type of a variable.

console.log(typeof "hello"); // Output: string
console.log(typeof 42); // Output: number
console.log(typeof true); // Output: boolean
console.log(typeof undefined); // Output: undefined
console.log(typeof null); // Output: object (this is a known
quirk in JS)
console.log(typeof {}); // Output: object
console.log(typeof []); // Output: object

3. instanceof Operator

Checks if an object is an instance of a particular class or constructor.

let arr = [1, 2, 3];
console.log(arr instanceof Array); // Output: true
console.log(arr instanceof Object); // Output: true

4. delete Operator

Removes a property from an object.

let user = { name: "Alice" , age: 25 };
delete user.age;
console.log(user); // Output: { name: "Alice" }

5. in Operator

Checks if a property exists in an object.

let person = { name: "John" , age: 30 };
console.log("age" in person); // Output: true
console.log("email" in person); // Output: false

6. void Operator

Evaluates an expression but returns undefined.

console.log(void 0); // Output: undefined
console.log(void (1 + 2)); // Output: undefined

Useful when you want to suppress a return value, especially in links or bookmarklets.

7. Comma Operator (,)

Allows multiple expressions to be evaluated, returning the last one.

let x = (1 + 2, 3 + 4);
console.log(x); // Output: 7

8. Optional Chaining Operator (?.)

Accesses deeply nested properties without throwing an error if a property doesn't exist.

let user = { name: "Alex" , address: { city: "NY" } };
console.log(user.address?.city); // Output: NY
console.log(user.contact?.email); // Output: undefined

9. Nullish Coalescing Operator (??)

Returns the right-hand value only if the left-hand is null or undefined.

let name = null;
let displayName = name ?? "Guest";
console.log(displayName); // Output: Guest

Contrast with || which also considers 0, "" , and false as falsy.

Summary Table

Operator	Purpose	Example	Output / Use
? :	Ternary (if-else)	age >= 18 ? "Yes" : "No"	"Yes" if age is 18+
typeof	Get data type	typeof 123	"number"
instance of	Check instance	[] instanceof Array	true
delete	Delete object property	delete obj.key	Property removed
in	Check if key exists in object	"key" in obj	true or false
void	Evaluate & return undefined	void 0	undefined
,	Comma (multiple expressions)	(1 + 2, 3 + 4)	7 (last result)
?.	Optional chaining	user?.profile?.name	Safe access
??	Nullish coalescing	value ?? "default"	"default" if value is null/undefined