altayaydemir / style-elements / Element.Events

This module is mirrored nearly completely from Html.Events

The only difference is that the HTML.Events are turned into Element.Events

Mouse Helpers

onClick : msg -> Element.Internal.Model.Attribute variation msg

onDoubleClick : msg -> Element.Internal.Model.Attribute variation msg

onMouseDown : msg -> Element.Internal.Model.Attribute variation msg

onMouseUp : msg -> Element.Internal.Model.Attribute variation msg

onMouseEnter : msg -> Element.Internal.Model.Attribute variation msg

onMouseLeave : msg -> Element.Internal.Model.Attribute variation msg

onMouseOver : msg -> Element.Internal.Model.Attribute variation msg

onMouseOut : msg -> Element.Internal.Model.Attribute variation msg

Form Helpers

onInput : (String -> msg) -> Element.Internal.Model.Attribute variation msg

Capture input events for things like text fields or text areas. It grabs the string value at event.target.value, so it will not work if you need some other type of information. For example, if you want to track inputs on a range slider, make a custom handler with on. For more details on how onInput works, check out targetValue.

onCheck : (Basics.Bool -> msg) -> Element.Internal.Model.Attribute variation msg

Capture change events on checkboxes. It will grab the boolean value from event.target.checked on any input event. Check out targetChecked for more details on how this works.

onSubmit : msg -> Element.Internal.Model.Attribute variation msg

Capture a submit event with preventDefault in order to prevent the form from changing the page’s location. If you need different behavior, use onWithOptions to create a customized version of onSubmit.

Focus Helpers

onBlur : msg -> Element.Internal.Model.Attribute variation msg

onFocus : msg -> Element.Internal.Model.Attribute variation msg

Custom Event Handlers

on : String -> Json.Decode.Decoder msg -> Element.Internal.Model.Attribute variation msg

Create a custom event listener. Normally this will not be necessary, but you have the power! Here is how onClick is defined for example:

import Json.Decode as Json

onClick : msg -> Attribute variation msg
onClick message =
    on "click" (Json.succeed message)

The first argument is the event name in the same format as with JavaScript's addEventListener function. The second argument is a JSON decoder. Read more about these here. When an event occurs, the decoder tries to turn the event object into an Elm value. If successful, the value is routed to your update function. In the case of onClick we always just succeed with the given message. If this is confusing, work through the Elm Architecture Tutorial. It really does help!

stopPropagationOn : String -> Json.Decode.Decoder ( msg, Basics.Bool ) -> Element.Internal.Model.Attribute variation msg

preventDefaultOn : String -> Json.Decode.Decoder ( msg, Basics.Bool ) -> Element.Internal.Model.Attribute variation msg

custom : String -> Json.Decode.Decoder { message : msg, stopPropagation : Basics.Bool, preventDefault : Basics.Bool } -> Element.Internal.Model.Attribute variation msg

Custom Decoders

targetValue : Json.Decode.Decoder String

A Json.Decoder for grabbing event.target.value. We use this to define onInput as follows:

import Json.Decode as Json

onInput : (String -> msg) -> Attribute msg
onInput tagger =
    on "input" (Json.map tagger targetValue)

You probably will never need this, but hopefully it gives some insights into how to make custom event handlers.

targetChecked : Json.Decode.Decoder Basics.Bool

A Json.Decoder for grabbing event.target.checked. We use this to define onCheck as follows:

import Json.Decode as Json

onCheck : (Bool -> msg) -> Attribute msg
onCheck tagger =
    on "input" (Json.map tagger targetChecked)

keyCode : Json.Decode.Decoder Basics.Int

A Json.Decoder for grabbing event.keyCode. This helps you define keyboard listeners like this:

import Json.Decode as Json

onKeyUp : (Int -> msg) -> Attribute msg
onKeyUp tagger =
    on "keyup" (Json.map tagger keyCode)

Note: It looks like the spec is moving away from event.keyCode and towards event.key. Once this is supported in more browsers, we may add helpers here for onKeyUp, onKeyDown, onKeyPress, etc.