DateTime comparison in dart - flutter

Question

I am trying to sort list of DateTime time elements in ascending order.I have realized normal operators like > or < don't cut it. What is the best way to compare two DateTime variables ?

Answer 1

Simply use the methods isAfter(), isBefore() or isAtSameMomentAs() from DateTime.
Other alternative, use compareTo(DateTime other), as in the docs:
Compares this DateTime object to [other],
returning zero if the values are equal.
Returns a negative value if this DateTime [isBefore] [other]. It returns 0
if it [isAtSameMomentAs] [other], and returns a positive value otherwise
(when this [isAfter] [other]).
Here a code example of sorting dates:
void main() {
var list = [
DateTime.now().add(Duration(days: 3)),
DateTime.now().add(Duration(days: 2)),
DateTime.now(),
DateTime.now().subtract(Duration(days: 1))
];
list.sort((a, b) => a.compareTo(b));
print(list);
}
See it working here.

Answer 2

This is I how understood and implemented the code it will result in true / false in boolean mode.
DateTime valEnd = edate ;
DateTime date =DateTime.now();
bool valDate = date.isBefore(valEnd);

Answer 3

DateTime comparison in dart
DateTime.compareTo(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");
if(dt1.compareTo(dt2) == 0){
print("Both date time are at same moment.");
}
if(dt1.compareTo(dt2) < 0){
print("DT1 is before DT2");
}
if(dt1.compareTo(dt2) > 0){
print("DT1 is after DT2");
}
DateTime.isAtSameMomentAs(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");
if(dt1.isAtSameMomentAs(dt2)){
print("Both DateTime are at same moment.");
}
DateTime.isAfter(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");
if(dt1.isAfter(dt2)){
print("DT1 is after DT2");
}
DateTime.isBefore(DateTime other):
DateTime dt1 = DateTime.parse("2021-12-23 11:47:00");
DateTime dt2 = DateTime.parse("2018-02-27 10:09:00");
if(dt1.isBefore(dt2)){
print("DT1 is before DT2");
}