Helpers for json manipulation with play-json

JsonExtensions.scala

package libs.json

object JsonOperations {

  import play.api.libs.json._

  def withDefault[A](key: String, default: A)(implicit writes: Writes[A]) = __.json.update((__ \ key).json.copyFrom((__ \ key).json.pick orElse Reads.pure(Json.toJson(default))))

  def copyKey(fromPath: JsPath,toPath:JsPath ) = __.json.update(toPath.json.copyFrom(fromPath.json.pick))

  def copyOptKey(fromPath: JsPath,toPath:JsPath ) = __.json.update(toPath.json.copyFrom(fromPath.json.pick orElse Reads.pure(JsNull)))

  def moveKeyWrites(fromPath:JsPath, toPath:JsPath) =(json:JsValue)=> json.transform(moveKeyReads(fromPath,toPath)).get

  def moveKeyReads(fromPath:JsPath, toPath:JsPath) =copyKey(fromPath,toPath) andThen fromPath.json.prune

  def inflateKey(keyName: Symbol) = __.json.update((__ \ 'version \ keyName).json.copyFrom((__ \ keyName).json.pick))

  def inflateOptKey(keyName: Symbol) = __.json.update((__ \ 'version \ keyName).json.copyFrom((__ \ keyName).json.pick orElse Reads.pure(JsNull)))

  def flattenKey(keyName: Symbol) = __.json.update((__ \ keyName).json.copyFrom((__ \ 'version \ keyName).json.pick))

  def flattenOptKey(keyName: Symbol) = __.json.update((__ \ keyName).json.copyFrom((__ \ 'version \ keyName).json.pick orElse Reads.pure(JsNull)))
}