js中二分搜索的使用

Array.prototype.binarySearch = function (item) {

  let low = 0;

  let high = this.length - 1;

  while (low <= high) {

    const mid = Math.floor((low + high) / 2);

    const element = this[mid];

    if (element < item) {

      low = mid + 1;

    } else if (element > item) {

      high = mid - 1;

    } else {

      return mid;

    }

  }

  return -1;

};

const arr = [1, 2, 3, 4, 5];

const res = arr.binarySearch(3);