function sortedUniqBy(array, iteratee) {
      return (array && array.length)
        ? baseSortedUniq(array, getIteratee(iteratee, 2))
        : [];
    }
This method is like `_.uniqBy` except that it's designed and optimized
for sorted arrays.

@static
@memberOf _
@since 4.0.0
@category Array
@param {Array} array The array to inspect.
@param {Function} [iteratee] The iteratee invoked per element.
@returns {Array} Returns the new duplicate free array.
@example

_.sortedUniqBy([1.1, 1.2, 2.3, 2.4], Math.floor);
// => [1.1, 2.3]