toIso8601String method

String toIso8601String()

Returns an ISO-8601 full-precision extended format representation.

The format is yyyy-MM-ddTHH:mm:ss.mmmuuuZ for UTC time, and yyyy-MM-ddTHH:mm:ss.mmmuuu (no trailing "Z") for local/non-UTC time, where:

  • yyyy is a, possibly negative, four digit representation of the year, if the year is in the range -9999 to 9999, otherwise it is a signed six digit representation of the year.
  • MM is the month in the range 01 to 12,
  • dd is the day of the month in the range 01 to 31,
  • HH are hours in the range 00 to 23,
  • mm are minutes in the range 00 to 59,
  • ss are seconds in the range 00 to 59 (no leap seconds),
  • mmm are milliseconds in the range 000 to 999, and
  • uuu are microseconds in the range 001 to 999. If microsecond equals 0, then this part is omitted.

The resulting string can be parsed back using parse.

final moonLanding = DateTime.utc(1969, 7, 20, 20, 18, 04);
final isoDate = moonLanding.toIso8601String();
print(isoDate); // 1969-07-20T20:18:04.000Z

Implementation

String toIso8601String() {
  String y =
      (year >= -9999 && year <= 9999) ? _fourDigits(year) : _sixDigits(year);
  String m = _twoDigits(month);
  String d = _twoDigits(day);
  String h = _twoDigits(hour);
  String min = _twoDigits(minute);
  String sec = _twoDigits(second);
  String ms = _threeDigits(millisecond);
  String us = microsecond == 0 ? "" : _threeDigits(microsecond);
  if (isUtc) {
    return "$y-$m-${d}T$h:$min:$sec.$ms${us}Z";
  } else {
    return "$y-$m-${d}T$h:$min:$sec.$ms$us";
  }
}