Changes

if worldcatId and worldcatId ~= '' then --if unsuppressed & present

table.insert( elements, p.createRow( 'WORLDCATID', '', worldcatId, '[[WorldCat Identities]]: [https://www.worldcat.org/identities/'..worldcatId..' '..worldcatId..']', false ) ) --Validation?

elseif worldcatId == nil then --if unsuppressed & absent

local viafId = parentArgs['VIAF']