Recursive actions with array

recursive-actions-with-array.js

const myArr = [1, 2, 5, 4, 7];

// Recursive sum:
function sum(arr) {
  if (arr.length === 0) return 0;
  return arr[0] + sum(arr.slice(1));
}
console.log(sum(myArr)); // 19


// Recursive array items count:
function arrayItemsCount(arr) {
  if (!arr.length) return 0;
  return 1 + arrayItemsCount(arr.slice(1));
}
console.log(arrayItemsCount(myArr)); // 5


// Recursive find biggest item:
function biggestItem(arr) {
  if (arr.length === 2) return arr[0] > arr[1] ? arr[0] : arr[1];
  const subMax = biggestItem(arr.slice(1));
  return arr[0] > subMax ? arr[0] : subMax;
}
console.log(biggestItem(myArr)); // 7