Populate Date if empty else do not change the date

[Mary Mark]

Hi Atlassian Community,

I have a workflow with 4 transitions.

For example: A, B and C, D.

When I go into B or C or D, populate the current date. The field is "Start Date"

For example, I go into B today with current date as December 16

Tomorrow if I go into C, the current date should not change to December 17 and remain as December 16 because date has already been populated unless there was no previous "Start Date" then populate it with the current date. 

Is there a way to achieve this via JSU post function. 

Please advise on any ideas. Any help is greatly appreciated.

Thank you. 

[Andrew Laden]

Since you have JSU, you can do this with JSU preconditions.

In work workflow post functions, first use the Value Field precondition (or even the fields required precondition) to test if the start date field is empty, then you can use the Update any field postfunction, and configure it to check the value of the pre-condition first.