JavaScript Data Types in Variables

Variables can hold different types of data:

String: Text, written inside quotes.

let message = "Hello, World!";
console.log(message); // Output: Hello, World!

Number: Integers or decimals.

let score = 99.5;
console.log(score); // Output: 99.5

Boolean: True or False.

let isLoggedIn = true;
console.log(isLoggedIn); // Output: true

Undefined: A variable declared but not assigned a value.

let test;
console.log(test); // Output: undefined

Null: Represents “no value.”

let value = null;
console.log(value); // Output: null

Object: Used to store multiple values.

let user = { name: "John", age: 30 };
console.log(user.name); // Output: John

JavaScript variables are dynamically typed, meaning a variable’s data type can change.

Example:

let data = 42; // Number
console.log(typeof data); // Output: number
data = "Hello"; // Now it's a string
console.log(typeof data); // Output: string