If you need to create a calculated field or put a conditional setting on a field in a rich text editor, then you may want to use the isNullOrEmpty function.

For example, if you want to create a conditional block in the Key Facts widget to not display a data item, you might use an expression like the following:

isNullOrEmpty(workItem.proceedingDetails.courtCaseReference) <> true

Creating a calculated field for use in a matching rule

Matching rule functionality allows you to set:

if(isNullOrEmpty(form-hdm-contentious.hdm-matter-contentious.name)=false,'Set','')