Var is the first keyword introduced to Javascript for declaring variables. This keyword is different from others and has unique properties and use cases. So before ES6 was introduced most people used the var keyword, but nowadays people stopped using this keyword because of these new keywords

ES6 Introduced 2 new keywords for declaring variables in Javascript.

1. Let: Accessible only Block level and can be reassigned.

2. Const: Accessible only Block level and can't be reassigned.

Introducing new keywords made var obsolete.

Differences

Code Examples

• Var Keyword

var name = "Prajwal Aradhya";
var counter = 3;
console.log(name); // Prajwal Aradhya
if (counter > 2) {
    var name = "Aradhya, Prajwal";
}
console.log(name); // Aradhya, Prajwal

• Let Keyword

let name = "Prajwal Aradhya";
let age = 10;

if (age % 5 === 0) {
    console.log("😁");
} else {
    console.log("😟");
}

• Const Keyword

const title = "A good movie";
const rating = 5;
// Movie "A good movie" has 5 🌟 rating.
console.log(`Movie "${title}" has ${rating} 🌟 rating.`);