Duration class Null safety

A span of time, such as 27 days, 4 hours, 12 minutes, and 3 seconds.

A Duration represents a difference from one point in time to another. The duration may be "negative" if the difference is from a later time to an earlier.

Durations are context independent. For example, a duration of 2 days is always 48 hours, even when it is added to a DateTime just when the time zone is about to do a daylight-savings switch. (See DateTime.add).

Despite the same name, a Duration object does not implement "Durations" as specified by ISO 8601. In particular, a duration object does not keep track of the individually provided members (such as "days" or "hours"), but only uses these arguments to compute the length of the corresponding time interval.

To create a new Duration object, use this class's single constructor giving the appropriate arguments:

Duration fastestMarathon = new Duration(hours:2, minutes:3, seconds:2);

The Duration is the sum of all individual parts. This means that individual parts can be larger than the next-bigger unit. For example, inMinutes can be greater than 59.

assert(fastestMarathon.inMinutes == 123);

All individual parts are allowed to be negative.

Use one of the properties, such as inDays, to retrieve the integer value of the Duration in the specified time unit. Note that the returned value is rounded down. For example,

Duration aLongWeekend = new Duration(hours:88);
assert(aLongWeekend.inDays == 3);

This class provides a collection of arithmetic and comparison operators, plus a set of constants useful for converting time units.

See DateTime to represent a point in time. See Stopwatch to measure time-spans.