Get to know the GlideDuration field

In ServiceNow you can use a GlideDuration field to store a duration.

Behind the scene a GlideDuration field is actually a timestamp, similar to a GlideDateTime field, and the the duration is stored as the time elapsed since january 1st 1970 0:00 GMT. So a GlideDuration with a value of 1 day is a timestamp representing january 2nd 0:00 GMT in the database.

The official documentation for GlideDuration is found here. It does however have a few black spots, which we will try to cover here.

Working with the Duration field as a numeric value

Working with a duration as a numeric value is often times the easiest way. With a numeric value is understood the number of miliseconds since january 1st 1970 0:00 GMT.

So to create a GlideDuration object we can do the following to create a duration of 1 day.

var duration = new GlideDuration(1 * 24 * 60 * 1000);

So the numeric value of 1444000 is the equalivant of 1 day or january 2nd 0:00 GMT in the database.

If you do not want a duration object, but wants to set the value of the field directly, you can use the setDateNumericValue function, since we understand, that a GlideDuration field is actually a datetime field, as explained earlier.

gr.duration_field.setDateNumericValue(1 * 24 * 60 * 1000);
gr.update();

In the above gr is a GlideRecord and duration_field is the column name of a GlideDuration field of the GlideRecord.

Comparing two durations

If we continue to work with durations by using their numeric value we can easily compare two durations fields using the dateNumericValue function.

As an example, if you want to compare two GlideDuration fields to establish, if one is larger than the other, you can do something similar to the below:

if(gr.field_one.dateNumericValue() > gr.field_two.dateNumericValue()){
    // Your logic
}

Adding or substracting durations

Adding or substracting also becomes easier when working with the duration’s numeric values.

Here is an example of adding one day to a GlideDuration field

var d = gr.duration_field.dateNumericValue() + (1 * 24 * 60 * 1000);
gr.duration_field.setDateNumericValue(d);
gr.update();

Tip: You can also use the dateNumericValue function to get the duration (difference) between two GlideDateTime fields by substracting their values.

Working with GlideDuration on a client script

On client scripts we cannot use the numeric value if we are working with the g_form object and wants to use the setValue function.

Here we need to adhere to a string format as the input using this format

DAYS HOURS:MINUTES:SECONDS

So to set a durations field to one day, we would use the following code where field is the name of the duration field.

g_form.setValue('field', '1 00:00:00');