Hackforge Academy

Explanation

Variables are used to store data in JavaScript. The keywords var, let, and const are used to declare variables. Modern JavaScript primarily uses let and const.

Code:

let name = 'Praveen';
const company = 'HackForge Academy';
console.log(name, company);

Explanation

JavaScript supports several primitive data types including String, Number, Boolean, Undefined, Null, and BigInt.

Code:

let username = 'John';
let age = 25;
let isActive = true;
let city;
let salary = null;

Explanation

The typeof operator is used to determine the data type of a variable at runtime.

Code:

console.log(typeof 'Hello');
console.log(typeof 100);
console.log(typeof true);

Explanation

JavaScript also supports complex data types such as Objects and Arrays, which can store collections of related data.

Code:

const student = {
  name: 'John',
  age: 22
};

const skills = ['HTML', 'CSS', 'JavaScript'];

Explanation

Variables can be updated when declared with let, while const variables cannot be reassigned after initialization.

Code:

let score = 50;
score = 75;

const country = 'India';
// country = 'USA'; // Error