JavaScript Data Types

Data types in JavaScript define the type of data that can be stored and manipulated within a program. They are essential for understanding how to work with variables and perform operations in JavaScript.

JavaScript has two main categories of data types: Primitive and Non-Primitive (or Reference) data types.

Primitive Data Types

Primitive data types are the most basic data types in JavaScript. They include:

String: Represents a sequence of characters. Example: "Hello, World!"
Number: Represents both integer and floating-point numbers. Example: 42, 3.14
Boolean: Represents logical entities. Can be either true or false.
Undefined: A variable that has been declared but not assigned a value.
Null: Represents the intentional absence of any object value.

Example Code

💡 Tip: Press F12 to open the console and see live results of each example!

// String
let name = "Ayush";
console.log(typeof name); // Output: string

// Number
let age = 25;
console.log(typeof age); // Output: number

// Boolean
let isStudent = false;
console.log(typeof isStudent); // Output: boolean

// Undefined
let x;
console.log(typeof x); // Output: undefined

// Null
let y = null;
console.log(typeof y); // Output: object

💡 Tip: In JavaScript, the typeof operator is used to determine the data type of a variable.

Non-Primitive Data Types

Non-Primitive data types are more complex and can store collections of data or more complex entities. They include:

Object: A collection of properties, where each property is a key-value pair. Example: { name: "Ayush", age: 21 }
Array: A special type of object used to store ordered collections of values. Example: [1, 2, 3, 4, 5]
Function: A block of code designed to perform a particular task. Functions are also objects in JavaScript.

Example Code

// Object
let person = { name: "Ayush", age: 21 };
console.log(typeof person); // Output: object

// Array
let numbers = [1, 2, 3, 4, 5];
console.log(typeof numbers); // Output: object

// Function
function greet() {
    return "Hello!";
}
console.log(typeof greet); // Output: function

JavaScript is a dynamically typed language, meaning you don't have to declare the data type of a variable explicitly. The type is determined automatically based on the value assigned to the variable.

💡 Tip: Use the typeof operator to check the data type of a variable.

Understanding these data types will help you write more effective JavaScript code!