javascript use of let and var

In JavaScript, let is a keyword that is used to declare a block scoped variable. Usually, the var keyword is treated as a normal variable, but the variables declared using the let keyword are block scoped.

let allows you to declare variables that are limited to the scope of a block statement, or expression on which it is used, unlike the var keyword, which declares a variable globally, or locally to an entire function regardless of block scope, javascript use of let and var.

Example: javascript use of let and var

let x = 2;

if (x === 2) 
{
  let x = 3;
  console.log("Inside scoped:" + x);
}

 console.log("Outside scoped:" + x);

OutPut :

• Inside scoped: 3
• Outside scoped: 2

As per above example we are using here let key word, first will assign variable let x  value to 2 and then after inside if block will re-assign variable let x value to 3

once code is executed will get re-assign value of let x=3 inside if code block only, but outside the code block it access the old value this is due to code-block variable accessibility of let keyword.

if here will use var key word instead of of let keyword then will get out  3 for both inside of if-block and outside of  if-block as mensioned below programe.

Example: javascript use of let and var

var x = 2;

if (x === 2) 
{
  var x = 3;
  console.log("Inside scoped:" + x);
}

 console.log("Inside scoped:" + x);

OutPut :

• Inside scoped: 3
• Outside scoped: 3