UI Designer Scripting: Check if field is null

I need to hide a field if it is null, so I've added a calculation rule to the 'Visible' attribute of the fields: However, neither of the below are working (First always returns false, the second one always returns true). I need to know how to check if a field is empty/null:

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dataField = $data.PRDLinkInternalID

if (dataField == null)

result = false

else

result = true

end

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dataField = $data.PRDLinkInternalID

if (dataField == “ “)

result = false

else

result = true

end

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