Stackoverflow: How to replace all the values with the same key in a JSON tree

gistfile1.scala

// Reply to: http://stackoverflow.com/questions/21801071/how-to-replace-all-the-values-with-the-same-key-in-a-json-tree/21804784#comment32996624_21804784

/**
 * If the object matches an $oid, return the value and the new key
 * Otherwise, return the original value
 */
def idOrValue(key: String, js: JsValue): (String, JsValue) = js \ "$oid" match {
  case JsUndefined() => key -> js
  case v => key -> v
}

def toPublic(json: JsValue) = json.updateAllKeyNodes {
  case ((_ \ "_id"), value) => idOrValue("id", value)
  case ((_ \ "accountId"), value) => idOrValue("accountId", value)
}