The Dart core library team was very conservative regarding dates and time for this reason. They kept things down to just DateTime (timezone aware, but only sup

The Dart core library team was very conservative regarding dates and time for this reason. They kept things down to just DateTime (timezone aware, but only supports local and UTC) and Duration, and assumed that anything more advanced should be outside the core. I'm not sure if they got it right or not, but we haven't seen anyone want to replace the built in types yet. I think we've always expected a Joda-Time like library eventually, but hopefully DateTime and Duration are good, so it's additive. (I'm on the Dart team, but not on the core lib team)