Почему алгоритм возвращает число - 1?

const array = [...Array(100).keys()].map(i => i + 1);

function binary_search(list, item) {
  let low = 0;
  let high = list.length;
  let middle;
  let isFound = false;

  while (isFound === false && low <= high) {
    debugger
    middle = Math.floor((low + high) / 2);

    if (list[middle] === item) {
      isFound = true;
      return middle;
    }
    if (item < list[middle]) {
      high = middle - 1;
    } else {
      low = middle + 1
    }
  }
  return 'Not found';
}

console.log(array);

console.log(binary_search(array, 24));