reverse6.js

//half index switch for loop
function reverseString6(str){
 let arr = str.split('');
  let len = arr.length, halfIndex = Math.floor(len / 2) - 1, tmp;
  for (let i = 0; i <= halfIndex; i++) {
    tmp = arr[len - i - 1];
    arr[len - i - 1] = arr[i];
    arr[i] = tmp;
  }