var VS. let

 

 


 

Differences Between the var and let Keywords :

 

Var :


One of the biggest problems with declaring variables with the var keyword is that you can easily overwrite variable declarations : 
var myName = "Hend";
var myName= "sara";
console.log(myName); \\ return Sara .

In this code ,the myName variable is originally declared as Hend, and is then overridden to be Sara .The console then displays the string Sara.

In a small application, you might not run into this type of problem. But as your codebase becomes larger, you might accidentally overwrite a variable that you did not intend to. Because this behavior does not throw an error, searching for and fixing bugs becomes more difficult.

 

 

Let :

A keyword called let was introduced in ES6,  to solve this issue with the var keyword.

If you replace var with let in the code above, it results in an error:

let myName= "Hend";
let myName= "Sara";

"The error can be seen in your browser console."

So unlike var, "when you use let, a variable with the same name can only be declared once."

so use let in your code to avoid the var issue.

 

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