code: function baseExtremum(array, iteratee, comparator) {
        var index = -1, length = array.length;
        while (++index < length) {
          var value = array[index], current = iteratee(value);
          if (current != null && (computed === undefined ? current === current : comparator(current, computed))) {
            var computed = current, result = value;
          }
        }
        return result;
      }
docs: The base implementation of methods like `_.max` and `_.min` which accepts a
  `comparator` to determine the extremum value.
  
  @private
  @param {Array} array The array to iterate over.
  @param {Function} iteratee The iteratee invoked per iteration.
  @param {Function} comparator The comparator used to compare values.
  @returns {*} Returns the extremum value.