mirror of https://github.com/status-im/reagent.git
135 lines
3.8 KiB
Markdown
135 lines
3.8 KiB
Markdown
|
|
# Reagent
|
|
|
|
A simple [ClojureScript](http://github.com/clojure/clojurescript) interface to [React](http://facebook.github.io/react/).
|
|
|
|
The main repository for Reagent is now located [here](https://github.com/reagent-project/reagent).
|
|
|
|
Reagent provides a way to write efficient React components using (almost) nothing but plain ClojureScript functions.
|
|
|
|
* **[Detailed intro with live examples](http://reagent-project.github.io/)**
|
|
* **[News](http://reagent-project.github.io/news/index.html)**
|
|
* **[Reagent Project Mailing List](https://groups.google.com/forum/#!forum/reagent-project)**
|
|
|
|
To use Reagent you add this to your dependencies in `project.clj`:
|
|
|
|
[reagent "0.4.3"]
|
|
|
|
You also need to include react.js itself. One way to do this is to add
|
|
|
|
:preamble ["reagent/react.js"]
|
|
|
|
to the *:compiler* section of project.clj, as shown in the examples
|
|
directory (or "reagent/react.min.js" in production). You could also
|
|
add
|
|
|
|
<script src="http://fb.me/react-0.9.0.js"></script>
|
|
|
|
directly to your html.
|
|
|
|
|
|
## Examples
|
|
|
|
Reagent uses [Hiccup-like](https://github.com/weavejester/hiccup) markup instead of React's sort-of html. It looks like this:
|
|
|
|
```clj
|
|
(defn some-component []
|
|
[:div
|
|
[:h3 "I am a component!"]
|
|
[:p.someclass
|
|
"I have " [:strong "bold"]
|
|
[:span {:style {:color "red"}} " and red"]
|
|
" text."]])
|
|
```
|
|
|
|
You can use one component inside another:
|
|
|
|
```clj
|
|
(defn calling-component []
|
|
[:div "Parent component"
|
|
[some-component]])
|
|
```
|
|
|
|
And pass properties from one component to another:
|
|
|
|
```clj
|
|
(defn child [name]
|
|
[:p "Hi, I am " name])
|
|
|
|
(defn childcaller []
|
|
[child "Foo Bar"])
|
|
```
|
|
|
|
You mount the component into the DOM like this:
|
|
|
|
```clj
|
|
(defn mountit []
|
|
(reagent/render-component [childcaller]
|
|
(.-body js/document)))
|
|
```
|
|
|
|
assuming we have imported Reagent like this:
|
|
|
|
```clj
|
|
(ns example
|
|
(:require [reagent.core :as reagent :refer [atom]]))
|
|
```
|
|
|
|
State is handled using Reagent's version of `atom`, like this:
|
|
|
|
```clj
|
|
(def click-count (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:
|
|
|
|
```clj
|
|
(defn timer-component []
|
|
(let [seconds-elapsed (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:
|
|
|
|
```clj
|
|
(def my-html (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 53K gzipped, using advanced compilation.
|
|
|
|
|
|
## About
|
|
|
|
The idea and some of the code for making components atom-like comes from [pump](https://github.com/piranha/pump). The reactive-atom idea (and some code) comes from [reflex](https://github.com/lynaghk/reflex).
|
|
|
|
The license is MIT.
|