I was able to get the result I was looking for by doing a Group by N with a group size of 0 and then a JSON formatter with Format Each Document and Pretty-Print checked. Then used a File Writer to create the expression library with the covcode data. Then I created another expression library with an expression to do a lookup from the original data fields to the covcode list that I could reference easily in a mapper. There were multiple places in my raw data that contained these covcodes, so this approach seems to reduce some additional snaps for me.
