Formatting a Duration like HH:mm:ss

Question

Is there a good way to format a Duration in something like hh:mm:ss, without having to deal with time zones?

I tried this:

DateTime durationDate = Da         


        

Answer 1

Elaborating on other answers, here is an implementation that also formats days:

extension DurationFormatter on Duration {
  /// Returns a day, hour, minute, second string representation of this `Duration`.
  ///
  ///
  /// Returns a string with days, hours, minutes, and seconds in the
  /// following format: `dd:HH:MM:SS`. For example,
  ///
  ///   var d = new Duration(days:19, hours:22, minutes:33);
  ///    d.dayHourMinuteSecondFormatted();  // "19:22:33:00"
  String dayHourMinuteSecondFormatted() {
    this.toString();
    return [
      this.inDays,
      this.inHours.remainder(24),
      this.inMinutes.remainder(60),
      this.inSeconds.remainder(60)
    ].map((seg) {
      return seg.toString().padLeft(2, '0');
    }).join(':');
  }
}

Unfortunately the intl package DateFormat class does not help: it marks the format of a Duration as not implemented:

formatDuration(DateTime reference) → String
NOT YET IMPLEMENTED. [...]