README.md

elm-json-codec

A library for creating combined encoders and decoders for Json in Elm, allowing composition.

With contributions from francescortiz

module Test exposing (..)

import Json.Decode as JD
import JsonCodec as JC
import Platform exposing (worker)

type alias Test = { i : Int, b : Bool, f : Float, o : Maybe String, s : String }
    
codec =
    Test
        |> JC.first  "i" JC.int .i
        |> JC.next   "b" JC.bool .b
        |> JC.next   "f" JC.float .f
        |> JC.option "o" (JC.nullable JC.string) .o Nothing
        |> JC.next   "s" JC.string .s
        |> JC.end

x =
    JD.decodeString (JC.decoder codec)
        "{\"i\":3,\"b\":false,\"f\":3.14,\"s\":\"hi there\"}"

y =
    JD.decodeString (JC.decoder codec)
        "{\"i\":3,\"b\":false,\"f\":3.14,\"o\":\"hi\",\"s\":\"hi there\"}"