Expression language : null values

Hi,

I'm trying to push an expiration date from Okta to Active Directory.

The date is not always defined as only temp contracts or trainnee have this field set in Okta.

I would like to only push values into the "AccountExpires" field when a date is set in the "EndDate" filed in Okta.

So far I've come up with :

user.endDate != null ? Time.fromIso8601ToWindows(Time.fromStringToIso8601(user.endDate,"dd/MM/YYYY")) : null

But this return an syntax error. However this is working :

user.endDate != "" ? Time.fromIso8601ToWindows(Time.fromStringToIso8601(user.endDate,"dd/MM/YYYY")) : ""

But will push "" in the AccountExpires field in ActiveDrectory when the source field is null.

What am I missing here ?