Block scope vs. functional scope

scope.js

/*
 var - functional scope == function declaration curly braces

 let/const - block scope == curly braxes
*/

for (let i=0; i<something.length; i++) {
  // i is only in here
}

// i is not valid here because of block scope

function myIterator() {
  for (var j=0; i<something.length; j++) {
    // j is in here
  }

 // j is also valid here because of functional scope
}