function sortedIndexBy(array, value, iteratee) {
      return baseSortedIndexBy(array, value, getIteratee(iteratee, 2));
    }
This method is like `_.sortedIndex` except that it accepts `iteratee`
which is invoked for `value` and each element of `array` to compute their
sort ranking. The iteratee is invoked with one argument: (value).

@static
@memberOf _
@since 4.0.0
@category Array
@param {Array} array The sorted array to inspect.
@param {*} value The value to evaluate.
@param {Function} [iteratee=_.identity] The iteratee invoked per element.
@returns {number} Returns the index at which `value` should be inserted
 into `array`.
@example

var objects = [{ 'x': 4 }, { 'x': 5 }];

_.sortedIndexBy(objects, { 'x': 4 }, function(o) { return o.x; });
// => 0

// The `_.property` iteratee shorthand.
_.sortedIndexBy(objects, { 'x': 4 }, 'x');
// => 0