📅  最后修改于: 2023-12-03 14:40:58.264000             🧑  作者: Mango
Elm-建筑是一种基于 Elm 编程语言的建筑框架,可以用于构建 Web 应用。 Elm-建筑采用模块化的架构,可以帮助程序员快速开发响应式、可扩展性和可组合性强的应用程序。
npm install elm-architecture
elm-architecture new my-app
src/Main.elm
中编写应用程序的主要逻辑。module Main exposing (..)
import Html exposing (..)
import Html.Events exposing (..)
type alias Model = Int
type Msg = Increment | Decrement
update : Msg -> Model -> Model
update msg model =
case msg of
Increment ->
model + 1
Decrement ->
model - 1
view : Model -> Html Msg
view model =
div []
[ button [ onClick Decrement ] [ text "-" ]
, div [] [ text (String.fromInt model) ]
, button [ onClick Increment ] [ text "+" ]
]
main : Program () Model Msg
main =
Html.program
{ init = (0, Cmd.none)
, update = update
, view = view
, subscriptions = \_ -> Sub.none
}
elm-architecture start
以下是一个简单的 Elm-建筑实例,用于显示当前时间:
module Main exposing (..)
import Html exposing (..)
import Time exposing (Posix)
import Task exposing (Task)
type alias Model = { currentTime : Posix }
type Msg = Tick Posix
type Subscription a = Time (Posix -> a)
update : Msg -> Model -> (Model, Cmd Msg)
update msg model =
case msg of
Tick newTime ->
( { model | currentTime = newTime }, Cmd.none )
subscriptions : Model -> Subscription Msg
subscriptions model =
Time.every (1000 * 60) Tick
view : Model -> Html Msg
view model =
let
formatTime time =
let
( hour, minute, second ) =
Time.toHourMinuteSecond time
hourString =
String.padLeft 2 '0' <| String.fromInt hour
minuteString =
String.padLeft 2 '0' <| String.fromInt minute
secondString =
String.padLeft 2 '0' <| String.fromInt second
in
hourString ++ ":" ++ minuteString ++ ":" ++ secondString
in
div []
[ text <| formatTime model.currentTime
]
main : Program () Model Msg
main =
Html.program
{ init = ( Model Time.now, Cmd.none )
, update = update
, view = view
, subscriptions = subscriptions
}
以上代码将每分钟更新一次应用程序的当前时间。可以通过以下命令运行此应用程序:
elm-architecture start