Auto populate field based on values from previous field

[Mohamad Hamizan bin Mohamad Salihin]

I have 3 fields in my Request Form: -

1. Start Date (Date picker)
2. End Date (Date picker)
3. Total Leave Days (Number field)

The request will be made in the portal and the scenario is as follows: -

1. User pick Start Date
2. User pick End Date
3. Total Leave Days field will be auto-populated with the difference of Start Date and End Date in days.

This scenario is supposed to be happening before the user submit the request. 

Below is my current automation rule for reference. The trigger i've chosen is "Issue created" which makes the rule to run only after a user has submitted a request. What i intended to do is for the Total Leave Days to be auto-populated WHILE the user is filling in the form within the portal. Is it possible to implement in automation? If it isn't, is there any workaround for this?

Thanks.

[Jenny Severin · Accepted solution]

Try entering this into the Total Leave Days:

{{issue.Start Date.diff(issue.End Date).days}}

[Mohamad Hamizan bin Mohamad Salihin]

Thank your for your response, @Jenny Severin

Yep. That is what I did in the Total Leave Days. It works just fine but only after the request has been submitted since I chose the "Issue created" trigger.

Just my concern is that whether this can be done while the request is being made in the portal. Perhaps a different trigger than the "Issue created" or any other workaround?

[Jenny Severin]

Sorry, but I do not believe it is possible to have the Total Leave Days field dynamically updated during portal entry.