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| layout | title | id |
|---|---|---|
| page | A JavaScript library for building user interfaces | home |
Just the UI
Lots of people use React as the V in MVC. Since React makes no assumptions about the rest of your technology stack, it's easy to try it out on a small feature in an existing project.
Virtual DOM
React uses a virtual DOM diff implementation for ultra-high performance. It can also render on the server using Node.js — no heavy browser DOM required.
Data flow
React implements one-way reactive data flow which reduces boilerplate and is easier to reason about than traditional data binding.
A Simple Component
React components implement a `render()` method that takes input data and returns what to display. This example uses an XML-like syntax called JSX. Input data that is passed into the component can be accessed by `render()` via `this.props`.
JSX is optional and not required to use React. Try clicking on "Compiled JS" to see the raw JavaScript code produced by the JSX compiler.
A Stateful Component
In addition to taking input data (accessed via `this.props`), a component can maintain internal state data (accessed via `this.state`). When a component's state data changes, the rendered markup will be updated by re-invoking `render()`.
An Application
Using `props` and `state`, we can put together a small Todo application. This example uses `state` to track the current list of items as well as the text that the user has entered. Although event handlers appear to be rendered inline, they will be collected and implemented using event delegation.
A Component Using External Plugins
React is flexible and provides hooks that allow you to interface with other libraries and frameworks. This example uses Showdown, an external Markdown library, to convert the textarea's value in real-time.