sort based on multiple properties

main.dart

class someclass {
  int quantity;
  DateTime mydate;
  
  someclass({this.quantity, this.mydate});
  
  int compareTo(someclass second) {
    int res = mydate.compareTo(second.mydate);
    if (res == 0) {
     return quantity.compareTo(second.quantity); 
    }
    return res;
  }
}

void main() {
  List<someclass> x = new List<someclass>();
  x.add(someclass(quantity: 2, mydate: DateTime.now()));
  x.add(someclass(quantity: 1, mydate: DateTime.now().add(Duration(days: 1))));
  x.add(someclass(quantity: 3, mydate: DateTime.now()));
  
  x.forEach((y) {
    print("---");
    print(y.quantity);
    print(y.mydate);
    print("---");
  });
  
  x.sort((a,b) => a.compareTo(b));
  
  x.forEach((y) {
    print("---");
    print(y.quantity);
    print(y.mydate);
    print("---");
  });
}