let vs var keyword

If you're new to learning JavaScript and have taken courses on youtube or anything other platform and don't really understand the difference between let and var or wondering why var isn't a standard in JavaScript anymore.
SAY NO MORE!

Let

first let's start with let. Let was introduced in ECMASCRIPT 6 === ES6 but you could use it a little bit in es5 for limited scope declarations. Wasn't until es6 that let and const were formerly introduced.

Stop using VAR!

Let is a great way to prevent bugs in your code. why you ask?

Because let is only limited to the scope of the block of code.
so lets say you have a function.

function user(){
let name = 'mike'
}

but you have another let name outside of the function.


let name = 'james';

remember all functions can access the global or root scope. so with let you cant reassign it, it can be modified but only inside the block scope.

Like this:

let = wizardLevel = false function user(){ wizardLevel = true; console.log('function',wizardLevel) <== returns true } user(); console.log(wizardLevel) <=== returns false // because it happened outside of the function scope. 

Look How var is accessed in if statment

var wizardLevel = false; var experience = 100; if(experience > 90){ wizardLevel = true; console.log('inside',wizardLevel); } console.log('outside', wizardLevel); 

Both wizardLevel variables will return true because of access to the scope. see image for results