This is the configuration required for automatic message-replay.

Let's say your program is initialized in HTML like this:

<script>
    const app = Elm.Main.init({
        node: document.body,
        flags: {
            amr : localStorage.getItem("app-amr")
        }
    })


    app.ports.toCache.subscribe(output =>
        localStorage.setItem("app-amr", output)
    )
</script>

The configuration for that script would be like this:

port toCache : Maybe String -> Cmd msg


fromCache =
    .amr

encodeMsg and msgDecoder depends how messages are defined. You can find an example here.

Create a “sandboxed” program that cannot communicate with the outside world. More about that here.

Create an HTML element managed by Elm. More about that here.

Create an HTML document managed by Elm. More about that here.

Create an application that manages Url changes. More about that here.

A program with automatic message-replay enabled.