JAVASCRIPT

Basic JavaScript: Use Recursion to Create a Countdown

function countdown(n){
  if (n < 1) {
    return [];
  } else {
    const arr = countdown(n - 1);
    arr.unshift(n);
    return arr;
  }
}
console.log(countdown(5)); // [5, 4, 3, 2, 1]

Use Recursion to Create a Countdown

function countdown(n){
   return n < 1 ? [] : [n].concat(countdown(n - 1));
}