Q1. Discuss the scope of var, let, and const

JavaScript provides three different ways to declare variables: var, let, and const. Each of them has its own scope rules, which can impact how variables are accessed and manipulated in different parts of your code. In this blog post, we will delve into the scope of var, let, and const to understand their differences and best use cases.

1. The var Keyword: Scope: Variables declared with var are function-scoped, meaning they are visible only within the function where they are declared. Hoisting: var variables are hoisted to the top of their scope, which means you can access them before they are declared in the code. Example:
function exampleFunction() { if (true) { var x = 10; console.log(x); // Outputs 10 } console.log(x); // Outputs 10 }

2. The let Keyword: Scope: Variables declared with let have block scope, meaning they are only accessible within the block (enclosed by curly braces) where they are defined. No Hoisting: Unlike var, let variables are not hoisted to the top of their scope. They only become available after the declaration. Example:
function exampleFunction() { if (true) { let y = 20; console.log(y); // Outputs 20 } // console.log(y); // ReferenceError: y is not defined }

3. The const Keyword: Scope: Like let, variables declared with const also have block scope. Immutable Values: The values assigned to const variables cannot be reassigned after declaration. However, it's important to note that const does not make objects or arrays themselves immutable, only their references. Example:

function exampleFunction() { const z = 30; // z = 40; // TypeError: Assignment to constant variable. console.log(z); // Outputs 30 }