simple example for Javascript closure

closure.js

function counter() {
  let count = 1;

  return function getCount() {
    count++;
    return count;
  }
}

const getCountA = counter();

for(let i = 0; i < 5; i++) {
  console.log('--- A: ', getCountA());
}

const getCountB = counter();

for(let i = 0; i < 5; i++) {
  console.log('--- B: ', getCountB());
}