import PersonalNumber.Swedish as PersonalNumber exposing (ValidationError(..)) personalNumber : String -> String personalNumber str = case PersonalNumber.fromString str of Ok pnr -> -- The `pnr` is wrapped in a `PersonalNumber` type and is -- guaranteed to be valid. Use the `display` function to turn -- it back into a user readable string. PersonalNumber.display pnr Err InvalidFormat -> "Not the correct format for a swedish personal number." Err InvalidLength -> "The personal number is not of the correct length." Err InvalidDate -> "The first part of the personal number needs to be a valid date." Err InvalidChecksum -> "One or more digits in the personal number is wrong."

import PersonalNumber.Swedish as PersonalNumber import Json.Decode exposing (Decoder, map2, field) import Json.Encode exposing (Value, object) type alias Person = { personalNumber : PersonalNumber.PersonalNumber } decoder : Decoder Person decoder = map2 Person (field "personal_number" PersonalNumber.decoder) encode : Person -> Value encode person = object [ ( "personal_number", PersonalNumber.encode person.personalNumber ) ]