Uso de variables no VAR fuera de funciones

function a () {
    let ar = 1
}

console.log(ar);

//console: TypeError: ar is not defined

/*
let and const are local variables, that means, if declared on function, then you will
not be able to use the variable, you must use it inside the function or declare
the variable in the file and not a local function
*/

function a () {
    let ar = 1
    
    console.log(ar);
}

const ar = 1
console.log(ar);

//console: 1 1
Eager Eel