This is an elm library for parsing parameters on the URL.

elm package install jessitron/elm-param-parsing

To use this, you'll need to create an input port, pass the search string to Elm, and then parse them with this function, then that can populate your model.

For instance, in the web page:

var app = Elm.fullscreen(Elm.YourModule,
           { locationSearch: window.location.search });

in YourModule.elm, declare the port and then parse what comes into it. This example discards errors:

import Dict exposing (Dict)

port locationSearch : String

parameters : Dict String String
parameters =
  case (parseSearchString locationSearch) of
    Error _ -> Dict.empty
    UrlParams dict -> dict

Then use that dict when you call your init function that needs the value of the parameter.

init (Dict.get parameters "customerID")

init : Maybe String -> Model
init maybeID = ...

The example app is built into this repo. source; result