testing_decoder_throway

testing_decoder.elm

module TestDecoder exposing (Node(..), input, main)

import Browser
import Html exposing (Html, button, div, text)
import Html.Events exposing (onClick)
import Json.Decode as Decode exposing (..)
import Json.Decode.Pipeline exposing (custom, hardcoded, optional, required)


type Node
    = Node String (List Node)


main : Html msg
main =
    text <| Debug.toString (Decode.decodeString (field "node" (list decodeNode)) input)



-- text <| Debug.toString (Decode.decodeString (Decode.at [ "map", "node" ] (list decodeNode)) input)


decodeNode : Decoder Node
decodeNode =
    Decode.map2 Node
        (field "@TEXT" string)
        nodeChildren


nodeChildren : Decoder (List Node)
nodeChildren =
    oneOf
        [ field "node" (list (lazy (\_ -> decodeNode)))
        , field "node" (map List.singleton (lazy (\_ -> decodeNode)))
        , succeed []
        ]


input =
    """{
 "node": [ 
        {
          "@TEXT": "1",
          "node": [
            {
              "@TEXT": "1.1"
            },
            {
              "@TEXT": "1.2"
            }
          ]
        },
        {
          "@TEXT": "2",
          "node": {
            "@TEXT": "2.1"
          }
        }
      ] 
    }


"""
-- this was created here : https://elmlang.slack.com/archives/C192T0Q1E/p1553603706828400