Datatypes in Js

Data Types in JavaScript

Data types in JavaScript define the type of value that a variable can store. JavaScript is a dynamically typed language, which means we do not need to specify the data type while declaring a variable. JavaScript automatically determines the data type based on the value assigned to the variable.

JavaScript data types are mainly divided into Primitive Data Types and Non-Primitive Data Types.

Primitive Data Types in JavaScript

• Primitive data types are the basic data types in JavaScript that represent a single value.
• Primitive values are immutable, which means their actual value cannot be changed after it is created. If we try to change a primitive value, JavaScript creates a new value instead of modifying the original value.

JavaScript has seven primitive data types:

• String
• Number
• BigInt
• Boolean
• Undefined
• Null
• Symbol

1. String

A String is used to store text or a sequence of characters. Strings can be written using single quotes, double quotes, or backticks.

let name = "John";

console.log(name);

Output:

John

2. Number

The Number data type is used to store numeric values, including integers and decimal (floating-point) numbers.

let age = 25;
let price = 99.50;

console.log(age);
console.log(price);

Output:

25
99.5

3. BigInt

BigInt is used to store very large integer values that cannot be safely represented by the regular Number data type. A BigInt value is created by adding n at the end of the number.

let bigNumber = 123456789012345678901234567890n;

console.log(bigNumber);

Output:

123456789012345678901234567890n

4. Boolean

The Boolean data type has only two possible values: true and false.

let isLoggedIn = true;

console.log(isLoggedIn);

Output:

true

5. Undefined

A variable has the value undefined when it has been declared but no value has been assigned to it.

let name;

console.log(name);

Output:

undefined

6. Null

null represents the intentional absence of a value. It is used when the programmer explicitly wants to indicate that a variable has no value.

let selectedUser = null;

console.log(selectedUser);

Output:

null

7. Symbol

Symbol is used to create unique values.

Primitive Data Types Summary

Data Type	Example	Description
String	"Hello"	Represents text
Number	25, 10.5	Represents numbers
BigInt	123n	Represents very large integers
Boolean	true, false	Represents true or false
Undefined	undefined	Variable declared without a value
Null	null	Represents intentional absence of a value
Symbol	Symbol("id")	Represents a unique value