unsafe elm json encoder+decoder

build.js

const compiler = require("node-elm-compiler")
const fs = require("async-file")

async function build() {
	const code = await compiler.compileToString("./src/Main.elm", { output: "main.js" })

	const patched = code
		.replace(`(jsonEncodeElmValue) {
	return author$project$MagicJson$jsonEncodeFakeValue;`,
	`(jsonEncodeElmValue) {
	return jsonEncodeElmValue;`)
		.replace(`(jsonDecodeJsonValue) {
	return author$project$MagicJson$jsonDecodeFakeValue;`,
	`(jsonDecodeJsonValue) {
	return elm$core$Maybe$Just(jsonDecodeJsonValue);`)

	return fs.writeFile('main.js', patched)
	    .catch((err) => { console.log("can't write file", err) })
}


build()

MagicJson.elm

module MagicJson exposing (encode, decode, decoder)


import Json.Encode as Encode exposing (Value)
import Json.Decode as Decode exposing (Decoder)
import Http


encode : a -> Value
encode jsonEncodeElmValue =
    jsonEncodeFakeValue


decode : Value -> Maybe a
decode jsonDecodeJsonValue =
    jsonDecodeFakeValue


decoder : Decoder a
decoder =
    Decode.map decode Decode.value
    |> Decode.andThen (\d ->
        case d of
            Just v -> Decode.succeed v
            Nothing -> Decode.fail "Impossible decoding of json"
        )

jsonDecodeFakeValue : Maybe a
jsonDecodeFakeValue =
    Nothing

jsonEncodeFakeValue : Value
jsonEncodeFakeValue =
    Encode.null

package.json

{
  "scripts": {
    "build": "node build.js"
  },
  "dependencies": {
    "async-file": "^2.0.2",
    "node-elm-compiler": "^5.0.3"
  }
}