Elmish.Dispatch

Operator alias for Elmish.Dispatch.handleMaybe (right-associative / precedence 0)

Operator alias for Elmish.Dispatch.handle (right-associative / precedence 0)

type Dispatch msg = msg -> Effect Unit

A function that a view can use to report messages originating from JS/DOM.

class Handle msg event f | f -> msg event where

Members

• handle :: Dispatch msg -> f -> EffectFn1 event Unit

  A convenience function to make construction of event handlers with arguments (i.e. EffectFn1) a bit shorter. The first parameter is a Dispatch. The second parameter can be either a message or a function from the event object to a message.

  Expected usage for this function is in its operator form <|

  textarea
    { value: state.text
    , onChange: dispatch <| \e -> TextAreaChanged (E.textareaText e)
    , onMouseDown: dispatch <| TextareaClicked
    }
  

Instances

• Handle msg event (event -> msg)
• Handle msg event msg

class HandleEffect event f | f -> event where

Members

• handleEffect :: f -> EffectFn1 event Unit

  An escape-hatch way to create an event handler for when neither handle nor handleMaybe are appropriate, which usually happens when the event handler must do something else, besides dispatching a message.

  The argument may be either an Effect Unit or a function from the event object to Effect Unit. If a message needs to be dispatched, the consuming code is expected to do it via calling the Dispatch function directly.

  div
    { onKeyDown: E.handleEffect \(E.KeyboardEvent e) -> do
        window >>= localStorage >>= setItem "Last key pressed" e.key
        dispatch PressedKey
    , onClick: E.handleEffect \e -> do
        E.stopPropagation e
        dispatch ClickedDiv
    }
  

Instances

• HandleEffect event (event -> Effect Unit)
• HandleEffect event (Effect Unit)

class HandleMaybe msg event f | f -> msg event where

Members

• handleMaybe :: Dispatch msg -> f -> EffectFn1 event Unit

  A variant of handle (aka <|) that allows to dispatch a message or not conditionally via returning a Maybe message.

  Expected usage for this function is in its operator form <?|

  div
    { onMouseDown: dispatch <?| \(E.MouseEvent e) ->
        if e.ctrlKey then Just ClickedWithControl else Nothing
    }
  

Instances

• (TypeEquals (t msg) (Maybe msg)) => HandleMaybe msg event (event -> t msg)
• (TypeEquals (t msg) (Maybe msg)) => HandleMaybe msg event (t msg)