function sortedLastIndexOf(array, value) {
      var length = array ? array.length : 0;
      if (length) {
        var index = baseSortedIndex(array, value, true) - 1;
        if (eq(array[index], value)) {
          return index;
        }
      }
      return -1;
    }
This method is like `_.lastIndexOf` 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 search.
@param {*} value The value to search for.
@returns {number} Returns the index of the matched value, else `-1`.
@example

_.sortedLastIndexOf([4, 5, 5, 5, 6], 5);
// => 3