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Difference Between var, let, and const in JavaScript

In JavaScript, there are three main ways to declare variables: var, let, and const.
Although they may look similar, they have important differences.

var

• Old declaration style (before ES6).
• Has function scope and does not respect block { } scope.

var x = 10;
if (true) {
  var x = 20;
}
console.log(x); // 20

let

• Introduced in ES6.
• Respects block scope { }.

let y = 10;
if (true) {
  let y = 20;
  console.log(y); // 20
}
console.log(y); // 10

const

• Similar to let but the value cannot be reassigned.

const PI = 3.1416;
// PI = 3; ❌ Error

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Use let for variables that may change and const for values that should not be modified.

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