在 JavaScript 中实现二分查找算法

function binarySearch(arr: number[], target: number): number {
  let lower: number = 0;
  let upper: number = arr.length - 1;
  let pos: number = -1;

  while (lower <= upper) {
    const mid: number = Math.floor((lower + upper) / 2);
    const num: number = arr[mid];

    if (num < target) {
      lower = mid + 1;
    } else if (num > target) {
      upper = mid - 1;
    } else {
      pos = mid;
      break;
    }
  }

  return pos;
}