4_2_reverse_array.js

function reverseArray(arr) {
  let newArr = [];
  for (let i = 0; i < arr.length; i++) {
    newArr.unshift(arr[i]);
  }
  return newArr;
}

function swap(arr, pos1, pos2) {
  const rem = arr[pos1];
  arr[pos1] = arr[pos2];
  arr[pos2] = rem;
}

function reverseArrayInPlace(arr) {
  for (let i = 0; i < arr.length / 2; i++) {
    swap(arr, i, arr.length - 1 - i);
  }
}

console.log(reverseArray(['A', 'B', 'C']));
// → ["C", "B", "A"];
let arrayValue = [1, 2, 3, 4, 5];
reverseArrayInPlace(arrayValue);
console.log(arrayValue);
// → [5, 4, 3, 2, 1]