ator, array, target)[1];
  },

  /**
   * Searches for the given target in the given array.
   *
   * @param  {(a: any, b: any) => number} comparator
   *         A function that takes two arguments and compares them, returning a
   *         negative number if the first should be ordered before the second,
   *         zero if the first and second have the same ordering, or a positive
   *         number if the second should be ordered before the first.  The first
   *         argument is always `target`, and the second argument is a value
   *         from the array.
   * @param  {Array} array
   *         An array whose elements are ordered by `comparator`.
   * @param  {any} target
   *         The value to search for.
   * @returns {Array} An array with two elements.  If `target` is found, the first
   *         element is true, and the second element is its index in the array.
   *         If `target` is not found, the first element is false, and the
   *         second element is the index where it may be inserted to keep the
   *         array ordered.
   */
  search(comparator, array, target) {
    let low = 0;
    let high = array.length - 1;
    while (low <= high) {
      // Thanks to http://jsperf.com/code-review-1480 for this tip.
      let mid = (low + high) >> 1;
      let cmp = comparator(target, array[mid]);
      if (cmp == 0) {
        return [true, mid];
      }
      if (cmp < 0) {
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
    return [false, low];
  },
});
PK