Make a copy scenario

try {
        let itemRecordNew = scriptContext.newRecord;
        if (scriptContext.type === scriptContext.UserEventType.COPY) {                      // set null if make a copy      
          itemRecordNew.setValue({
            fieldId: fieldId,
            value: null
          });
        }
      }
      catch (err) {
        log.debug("error@beforeLoad", err);
      }