extentBy<T, R extends Comparable<Object>> function

(R, R)? extentBy<T, R extends Comparable<Object>>(Iterable<T> iterable, R accessor(T))

Returns the minimum and maximum values using an accessor function.

Implementation

(R, R)? extentBy<T, R extends Comparable<Object>>(
  Iterable<T> iterable,
  R Function(T) accessor,
) {
  final iterator = iterable.iterator;
  if (!iterator.moveNext()) return null;

  R minValue = accessor(iterator.current);
  R maxValue = minValue;

  while (iterator.moveNext()) {
    final value = accessor(iterator.current);
    if (value.compareTo(minValue) < 0) {
      minValue = value;
    }
    if (value.compareTo(maxValue) > 0) {
      maxValue = value;
    }
  }
  return (minValue, maxValue);
}