Duration difference(
DateTime other
)

Returns a Duration with the difference between this and other.

DateTime berlinWallFell = new DateTime(1989, DateTime.NOVEMBER, 9);
DateTime dDay = new DateTime(1944, DateTime.JUNE, 6);

Duration difference = berlinWallFell.difference(dDay);
assert(difference.inDays == 16592);

Source

/**
 * Returns a [Duration] with the difference between [this] and [other].
 *
 *     DateTime berlinWallFell = new DateTime(1989, DateTime.NOVEMBER, 9);
 *     DateTime dDay = new DateTime(1944, DateTime.JUNE, 6);
 *
 *     Duration difference = berlinWallFell.difference(dDay);
 *     assert(difference.inDays == 16592);
 */

Duration difference(DateTime other) {
  int ms = millisecondsSinceEpoch;
  int otherMs = other.millisecondsSinceEpoch;
  return new Duration(milliseconds: ms - otherMs);
}