JavaScript Data Types

Primitive Data Types

Definition: Primitive data types are the basic data types in JavaScript. They hold a single value and are immutable.

Data Type	Description	Example
String	Textual data	let name = "Rohan";
Number	Numeric values	let age = 25;
Boolean	True or False	let isOnline = true;
Undefined	Variable declared but not assigned	let x;
Null	Intentional absence of value	let y = null;
Symbol	Unique and immutable value	let id = Symbol("id");
BigInt	Large integers	let big = 123456789123456789n;

Non-Primitive (Reference) Data Types

Definition: Non-primitive data types can store collections of values or more complex entities and are mutable.

Data Type	Description	Example
Object	Key-value pairs	let person = { name: "Rohan", age: 25 };
Array	Ordered list of values	let fruits = ["apple", "banana"];
Function	Reusable block of code	function greet() { alert("Hello"); }