Binary search boundaries

/**
 * Returns an index i with sorted[i] === target, or -1 when the target is
 * absent. `sorted` is ascending and may contain duplicates.
 */
export function binarySearch(sorted: number[], target: number): number {
  let low = 0
  let ____ = sorted.length - 1

  while (low ___ high) {
    const ___ = Math.floor((low + high) / 2)
    const guess = sorted[mid]

    if (guess === target) return mid
    if (guess < target) {
      low = mid + 1
    } else {
      high = mid - 1
    }
  }

  return -1
}