decoders.elm

Model.elm

boardDecoder : Decode.Decoder (Dict Position Cell)
boardDecoder =
    let
        asTuple : CellWrapper -> ( Position, Cell )
        asTuple cw =
            ( cw.pos, cw.cell )

        toDict : List CellWrapper -> Dict Position Cell
        toDict wrappers =
            wrappers |> List.map asTuple |> Dict.fromList
    in
        (Decode.list decodeCellWrapper)
            |> Decode.map toDict


decodeCellWrapper : Decode.Decoder CellWrapper
decodeCellWrapper =
    Decode.map2 CellWrapper
        (field "pos" positionDecoder)
        (field "cell" cellDecoder)

boardEncoder : Dict.Dict Position Cell -> Encode.Value
boardEncoder board =
    board
        |> Dict.toList
        |> List.map (\( pos, cell ) -> { pos = pos, cell = cell })
        |> List.map cellWrapperEncoder
        |> Encode.list   
        
cellWrapperEncoder : CellWrapper -> Encode.Value
cellWrapperEncoder v =
    Encode.object
        [ ( "pos", positionEncoder v.pos )
        , ( "cell", cellEncoder v.cell )
        ]