ConstraintFormat.pattern alternative

JsConstraints.scala

package helpers

import play.api.libs.json.Reads
import play.api.data.validation.ValidationError
import play.api.libs.json.JsError
import play.api.libs.json.JsSuccess

// Use instead of ConstraintFormat.pattern
object JsConstraints {
  def regex(r: => scala.util.matching.Regex, error: String = "error.pattern")(implicit reads: Reads[String]) =
    Reads[String](js => reads.reads(js).flatMap { o =>
      r.unapplySeq(o).map(_ => JsSuccess(o)).getOrElse(JsError(ValidationError(error, r)))
    })
}