GREL (Google Refine Expression Language) to extract ISSN from the GOKb Co-referencing service. Gives appropriate errors if multiple records or multiple ISSNs in GOKb Co-reference Service response

extract-coref-issn

if(
  length(value.parseJson()["records"])>1,
  "Multiple Records match that identifier, check CRED (Web UI) for errors",
  with(
    filter(value.parseJson()["records"][0]["sameAs"],v,v["namespace"]=="issn"), 
    issns,
    if(length(issns)>1,"Multiple ISSNs for one Title": ","") + forEach(issns,v,v["identifier"]).join(",")
    )
  )
)