Validate #Json with pure #JsObject #transformer #Reads #Play2.1

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CODE.scala

import play.api.libs.json._
import play.api.data.validation._
import play.api.libs.functional.syntax._
 
val json = Json.obj(
"name" -> "John",
"email" -> "john.doe@company.com",
"password" -> "password",
"confirmPassword" -> "password"
)
 
val json2 = Json.obj(
"name" -> "John",
"email" -> "john.doe@company.com",
"password" -> "password",
"confirmPassword" -> "password2"
)
 
// pick json as JsObject only if password is validated 
val passwordValidator = 
  __.json.pick[JsObject] keepAnd 
  (
    (
      (__ \ "password").read[String] and
      (__ \ "confirmPassword").read[String]
    ).tupled.filter(ValidationError("password not confirmed")){ case(pwd, confPwd) => pwd == confPwd }
  )
 

Test.scala

scala> passwordValidator.reads(json)
res8: play.api.libs.json.JsResult[play.api.libs.json.JsObject] =
JsSuccess({"name":"John","email":"john.doe@company.com","password":"password","confirmPassword":"password"},)

scala> passwordValidator.reads(json2)
res9: play.api.libs.json.JsResult[play.api.libs.json.JsObject] =
JsError(List((,List(ValidationError(password not confirmed,WrappedArray())))))