nifi-extension-bundles/nifi-jslt-bundle/nifi-jslt-processors/src/test/resources/cardinalityTransform.json

def first(node)
  if (is-array($node))
    $node[0]
  else
    $node


{
  "rating": {
    for(.rating)
    .key : {
      "value": first(."value".value)
    }
  }
}