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DIFFICULTY LEVEL: INTERMEDIATE
Assumes having taken the class SSNF and has good intermediate level of knowledge and/or familiarity with Scripting in ServiceNow.
So I get asked this question a lot: The GlideDateTime DateDiff functionality does not seem to work like I want. Is there another method for obtaining a difference?
The answer is Yes!
The solution actually utilizes GlideDateTime functions to obtain the answer; which I encapsulated in a function to simplify matters.
I created the following function as an example. It simply takes a GlideDateTime value passed-in as a parameter, converts that to milliseconds, and then subtracts that from the current date/time (in milliseconds), and returns the result in days. You can make this more generic if needed, or perhaps pass a second date/time value in to get a diff between two different dates (not just the current date).
const DAY = 24*60*60*1000; // milliseconds in a day
// dateTimeValue = GlideDateTime
// tzOffSet = boolean (true/false)
function Time_Difference(dateTimeValue, tzOffSet) {
// apply timezone offset
var offSet = tzOffSet ? dateTimeValue.getTZOffset() : 0.0000;
// get the milliseconds value of the passed-in date/time
// assumption: if timezone offset chosen then this value is in local date/time
var dateTimeMilli = dateTimeValue.getNumericValue();
// get the current date/time value and convert it to milliseconds
var gtNowMilli = new GlideDateTime().getNumericValue() + offSet;
// now return the diff and pass it back converted to days
return (gtNowMilli - dateTimeMilli) / DAY;
}
A usage for this function might be to check the number of days between a date and today. That would look something like this:
const DAY = 24*60*60*1000; // milliseconds in a day
var date_time_value = new GlideDateTime('2023-07-04 03:58:12');
gs.info('---> date_time_value: ' + date_time_value);
var diff = Time_Difference(date_time_value, false);
// time zone adjustment of original date
var offSetTZ = date_time_value.getTZOffset();
date_time_value.setNumericValue(date_time_value.getNumericValue() + offSetTZ);
gs.info('---> dateTimeValueTZ: ' + date_time_value);
var diffTZ = Time_Difference(date_time_value, true);
// results
gs.info('---> diff in days:' + diff);
gs.info('---> diffTZ in days:' + diffTZ);
// end test
function Time_Difference(dateTimeValue, tzOffSet) {
var offSet = tzOffSet ? dateTimeValue.getTZOffset() : 0.0000;
var dateTimeMilli = dateTimeValue.getNumericValue();
var gtNowMilli = new GlideDateTime().getNumericValue() + offSet;
return (gtNowMilli - dateTimeMilli) / DAY;
}
Which would give the following result:
*** Script: ---> date_time_value: 2023-07-04 03:58:12
*** Script: ---> dateTimeValueTZ: 2023-07-03 20:58:12
*** Script: ---> diff in days:124.82145049768519
*** Script: ---> diffTZ in days:124.82145050925926
Try it out in Scripts - Background! Play around with the date value and see the difference. You will find this is pretty acccurate.
Enjoy!
Steven Bell.
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Originally published on: 07-23-2018 11:44 AM
I updated the code and brought the article into alignment with my new formatting standard.
