elm-review-extract-api

An elm-review rule with extractor to extract the public interface (that is ports, their types, and flags) of all entrypoints in an Elm application.

Say what now?

Imagine you have this beautiful application:

port module Main exposing (main)


port send : { data : String, finished : Bool } -> Cmd msg


port recv : (List String -> msg) -> Sub msg


type alias Flags =
    { more : String
    , stuff : Int
    }


main : Program Flags () ()
main =
    Platform.worker
        { init = \_ -> ( (), Cmd.none )
        , update = \_ _ -> ( (), send { data = "hi", finished = False } )
        , subscriptions = \_ -> recv (\_ -> ())
        }

Now, with this rule configured, running elm-review --report=json --extract can yield us this extract:

{
    "ports": {
        "send": {
            "type": "record",
            "fields": {
                "data": "string",
                "finished": "bool"
            }
        },
        "recv": {
            "type": "list",
            "content": "string"
        }
    },
    "entryPoints": {
        "Main": {
            "cmds": ["send"],
            "subs": ["recv"],
            "flags": {
                "type": "record",
                "fields": {
                    "more": "string",
                    "stuff": "int"
                }
            }
        }
    }
}

Having this information isn't particularily valuable on its own, but it can be used for further processing, such as generating typescript definition files to ensure you use your app correctly!