code: function sortedIndexOf(array, value) {
        var length = array == null ? 0 : array.length;
        if (length) {
          var index = baseSortedIndex(array, value);
          if (index < length && eq(array[index], value)) {
            return index;
          }
        }
        return -1;
      }
docs: This method is like `_.indexOf` except that it performs a binary
  search on a sorted `array`.
  
  @static
  @memberOf _
  @since 4.0.0
  @category Array
  @param {Array} array The array to inspect.
  @param {*} value The value to search for.
  @returns {number} Returns the index of the matched value, else `-1`.
  @example
  
  _.sortedIndexOf([4, 5, 5, 5, 6], 5);
  // => 1