Reagent

React.js的一个极简的ClojureScript接口。(A minimalistic ClojureScript interface to React.js. )

Github星跟蹤圖

Reagent 提供了 ClojureScript 和 React 之间的简约接口。 它允许您使用纯粹的 ClojureScript 函数和数据定义高效的 React 组件,它们使用类似 Hiccup 的语法来描述您的UI。\r\n

Reagent 的目标是通过使用几个基本概念来定义任意复杂的UI,并且默认情况下足够快,你几乎不需要关心性能。\r\n

需求
    \r\n\t
  • JDK 1.7+
  • \r\n\t
  • Leiningen 2.x
  • \r\n
用法

要创建一个新的Reagent项目,只需运行:\r\n

<code>lein new reagent myproject\r\n</code>\r\n

如果您只想在没有Clojure后端的情况下创建ClojureScript的资源,请执行以下操作:\r\n

<code>lein new reagent-frontend myproject\r\n</code>\r\n

这将建立一个新的试剂项目,并提供一些合理的默认值,详见这里。\r\n

概覽

名稱與所有者reagent-project/reagent
主編程語言Clojure
編程語言JavaScript (語言數: 6)
平台
許可證MIT License
發布數45
最新版本名稱v1.2.0 (發布於 2023-02-16 17:29:46)
第一版名稱v0.0.2 (發布於 )
創建於2013-12-18 18:12:03
推送於2023-12-01 14:16:37
最后一次提交2023-03-11 23:28:22
星數4.7k
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提交數1.6k
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Reagent

Reagent-Project

A simple ClojureScript interface to React.

Reagent provides a way to write efficient React components using (almost) nothing but plain ClojureScript functions.

Usage

To create a new Reagent project using Leiningen template simply run:

lein new reagent myproject

If you wish to only create the assets for ClojureScript without a Clojure backend then do the following instead:

lein new reagent-frontend myproject

This will setup a new Reagent project with some reasonable defaults, see here for more details.

To use Reagent in an existing project you add this to your dependencies in project.clj:

Clojars Project
CircleCI

This is all you need to do if you want the standard version of React. If you want to use your own build of React (or React from a CDN), you have to use :exclusions variant of the dependency, and also provide react and react-dom namespaces (by creating .cljs files with just ns form, or by adding your own :foreign-libs entries).

[reagent "0.x.x" :exclusions [cljsjs/react cljsjs/react-dom]]

Examples

Reagent uses Hiccup-like markup instead of React's sort-of html. It looks like this:

(defn some-component []
  [:div
   [:h3 "I am a component!"]
   [:p.someclass
    "I have " [:strong "bold"]
    [:span {:style {:color "red"}} " and red"]
    " text."]])

Reagent extends standard Hiccup in one way: it is possible to "squeeze" elements together by using a > character.

[:div
  [:p
    [:b "Nested Element"]]]

can be written as:

[:div>p>b "Nested Element"]

Since version 0.8: The :class attribute also supports collections of classes, and nil values are removed:

[:div {:class ["a-class" (when active? "active") "b-class"]}]

You can use one component inside another:

(defn calling-component []
  [:div "Parent component"
   [some-component]])

And pass properties from one component to another:

(defn child [name]
  [:p "Hi, I am " name])

(defn childcaller []
  [child "Foo Bar"])

You mount the component into the DOM like this:

(defn mountit []
  (r/render [childcaller]
            (.-body js/document)))

assuming we have imported Reagent like this:

(ns example
  (:require [reagent.core :as r]))

State is handled using Reagent's version of atom, like this:

(defonce click-count (r/atom 0))

(defn state-ful-with-atom []
  [:div {:on-click #(swap! click-count inc)}
   "I have been clicked " @click-count " times."])

Any component that dereferences a reagent.core/atom will be automatically re-rendered.

If you want do some setting up when the component is first created, the component function can return a new function that will be called to do the actual rendering:

(defn timer-component []
  (let [seconds-elapsed (r/atom 0)]
    (fn []
      (js/setTimeout #(swap! seconds-elapsed inc) 1000)
      [:div
       "Seconds Elapsed: " @seconds-elapsed])))

This way you can avoid using React's lifecycle callbacks like getInitialState and componentWillMount most of the time.

But you can still use them if you want to, either using reagent.core/create-class or by attaching meta-data to a component function:

(defonce my-html (r/atom ""))

(defn plain-component []
  [:p "My html is " @my-html])

(def component-with-callback
  (with-meta plain-component
    {:component-did-mount
     (fn [this]
       (reset! my-html (.-innerHTML (reagent/dom-node this))))}))

See the examples directory for more examples.

Performance

React is pretty darn fast, and so is Reagent. It should even be faster than plain old javascript React a lot of the time, since ClojureScript allows us to skip a lot of unnecessary rendering (through judicious use of React's shouldComponentUpdate).

The ClojureScript overhead is kept down, thanks to lots of caching.

Code size is a little bigger than React.js, but still quite small. The todomvc example clocks in at roughly 79K gzipped, using advanced compilation.

About

The idea and some of the code for making components atom-like comes from pump. The reactive-atom idea (and some code) comes from reflex.

The license is MIT.

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