According to the official Automation For Jira DC documentation, it is currently possible to check a condition using the if smart value, however, it is not possible to set an else to this if.

Suggestion

The if function could have a possibility to set a value if the condition is not matched - something like worksheets-functions allow such as:

{{if(smartValue, "value if true", "value if false")}} 

Example

We need to filter some issues with a lookup, depending on the summary. If the summary is numeric I will check for a project and if it's not, I'll check a different project. Currently what can be done is something like the following:

statusCategory = Done {{if(issue.Summary.isNumeric(), "and project = GT")}} 

With the suggestion, we would be able to do something like:

statusCategory = Done {{if(issue.Summary.isNumeric(), "and project = GT", "and project = TEST")}} 

Workaround

As a workaround, we need to use the if/else blocks.