toMmSs method
Returns a zero-padded MM:SS string (e.g. "23:45").
Useful for short timers and music players.
Implementation
String toMmSs() {
final abs = this.abs();
final m = abs.inMinutes.toString().padLeft(2, '0');
final s = abs.inSeconds.remainder(60).toString().padLeft(2, '0');
return '${isNegative ? '-' : ''}$m:$s';
}