A web scripting language is called JavaScript. It contains its own data types, much like any other computer language. The type of data that a variable can carry is defined by its data type in a language.

There are eight basic data types in JavaScript.

Data TypesDescriptionExample
StringRepresents textual datalet str = 'Hi', let str2 = "Hello", let str3 = `Hello World`
NumberAn integer or a floating-point numberlet num = 3, let num2 = 3.234, let num3 = 3e-2
BigIntAn integer with arbitrary precisionlet num = 900719925124740999n, let num = 1n
BooleanAny of two values: true or falselet flag = true
undefinedA data type whose variable is not initializedlet a;
nullDenotes a null valuelet a = null;
SymbolData type whose instances are unique and immutablelet value = Symbol('hello');
Objectkey-value pairs of collection of datalet student = { };
Table - Different Data Types in JavaScript


Text is stored in strings. Strings in JavaScript are enclosed in quotes:

  • Single quotes: 'Hello'
  • Double quotes: "Hello"
  • Backticks: `Hello`


// Strings
const firstName = "Code";
const lastName = "Solution";
const result = `Name: ${firstName} ${lastName}`;

console.log(result); // Name: Code Solution


Numerals represent floating-point and integer numbers (decimals and exponentials). Additionally, a number type can be +Infinity, -Infinity, or NaN. (not a number).

const number1 = 3;
const number2 = 3.433;
const number3 = 3e5; // 3 * 10^5

const number4 = 3 / 0;
console.log(number4); // Infinity

const number5 = -3 / 0;
console.log(number5); // -Infinity

// strings can't be divided by numbers
const number6 = "abc" / 3;
console.log(number6); // NaN


Only numbers less than and greater than -(2sup>53/sup> -1) can be represented using the Number type in JavaScript. However, you can use the BigInt data type if you require a larger number than that.

By adding n to the end of an integer, a BigInt number is produced.

// BigInt value
const num1 = 900719925124740998n;
const num2 = 900719925124740998n;
const num3 = 10;

// Adding two big integers
const result1 = num1 + num2;
console.log(result1); // "1801439850249481996n"

// Error! BitInt and number cannot be added
const result2 = num1 + num2 + num3; 
console.log(result2);  // Uncaught TypeError: Cannot mix BigInt and other types


This data type represents logical entities. Boolean values can only be either true or false.

const dataChecked = true;
const valueCounted = false;


A value that is not assigned is represented by the undefined data type. A variable's value will be undefined if it is declared but its value is not yet assigned.

let name;
console.log(name); // undefined

let name = undefined;
console.log(name); // undefined


Null is a special value in JavaScript that denotes an empty or undefined value.

const number = null;


Symbol values can be defined as values with the data type Symbol. Symbol is a singular, immutable primitive value.

// Two symbols with the same description

const value1 = Symbol('hello');
const value2 = Symbol('hello');

let result = (value1 === value2) ? true : false;  // false;

// Note: Though value1 and value2 both contain 'hello', they are different as they are of the Symbol type.


A complicated data type called an object enables us to store data collections.

const employee = {
    firstName: 'John',
    lastName: 'K',
    email: '[email protected]'

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