1function binarySearch(arr, target) {
2 let lo = 0;
3 let hi = arr.length - 1;
4 while (lo <= hi) {
5 const mid = Math.floor((lo + hi) / 2);
6 if (arr[mid] === target) {
7 return mid;
8 } else if (arr[mid] < target) {
9 lo = mid + 1;
10 } else {
11 hi = mid - 1;
12 }
13 }
14 return -1;
15}