How to set focus on an element in Elm?

Question

How can I set the focus on a Html element in Elm? I tried to set the autofocus attribute on the element and it only sets the focus on the page load.

Answer 1

The focus function in the elm-lang/dom package is used to set focus with a Task (without using any ports or JavaScript).

Internally it uses requestAnimationFrame to ensure any new DOM updates are rendered before it tries to find the DOM node to focus on.

An example use:

type Msg     = FocusOn String     | FocusResult (Result Dom.Error ())  update : Msg -> Model -> ( Model, Cmd Msg ) update msg model =     case msg of         FocusOn id ->             ( model, Dom.focus id |> Task.attempt FocusResult )          FocusResult result ->             -- handle success or failure here             case result of                 Err (Dom.NotFound id) ->                     -- unable to find dom 'id'                 Ok () ->                     -- successfully focus the dom 

Full example on Ellie