search in array

function binarySearch(arr, target) {
  let start = 0
  let end = arr.length - 1
  while (start <= end) {
    const mid = Math.floor((start + end) / 2)
    if (arr[mid] === target) {
      return mid
    } else if (arr[mid] < target) {
      start = mid + 1
    } else {
      end = mid - 1
    }
  }
  return -1
}