Calcualting duration between two date fields in scoped application

[Chad7]

I'm used to calculating duration fields using dateDiff, but since that doesn't work in my scoped application, I'm having to use GlideDateTime.subtract, which I can't get to work on my business rule that is triggered when the start date or stop date changes. Can anyone tell me why this script isn't working as written? I get no errors, but the degradation_duration field just remains blank.

var start = new GlideDateTime(current.degradation_start.getDisplayValue());
var stop = new GlideDateTime(current.degradation_stop.getDisplayValue());
var duration = GlideDateTime.subtract(start, stop).getDisplayValue();

current.degradation_duration = duration.getDisplayValue();

[Abhinay Erra · Accepted solution]

You are almost there, only think is you need to take out the display value while setting to the duration. Use this code

var start = new GlideDateTime(current.degradation_start.getDisplayValue()); 
var stop = new GlideDateTime(current.degradation_stop.getDisplayValue()); 
var duration = GlideDateTime.subtract(start, stop); 
current.degradation_duration = duration;

[Chad7]

Thanks, that seems to have done the trick.