docs: function sortedIndex(element) {
      /* jshint validthis:true */
      var index = binarySearch(toArray(this), element, this.comparator);
  
      if (index < 0) {
          // binarySearch decreases the negative index by one because otherwise the index 0 would stand for two results
          // @see https://github.com/darkskyapp/binary-search/issues/1
          return Math.abs(index) - 1;
      } else {
          return index;
      }
  }