Getting Started

JSFiddle #

The easiest way to start hacking on React is using the following JSFiddle Hello World examples:

Using React from npm #

We recommend using React with a CommonJS module system like browserify or webpack. Use the react and react-dom npm packages.

// main.js
var React = require('react');
var ReactDOM = require('react-dom');

ReactDOM.render(
  <h1>Hello, world!</h1>,
  document.getElementById('example')
);

To install React DOM and build your bundle with browserify:

$ npm install --save react react-dom babelify babel-preset-react
$ browserify -t [ babelify --presets [ react ] ] main.js -o bundle.js

To install React DOM and build your bundle with webpack:

$ npm install --save react react-dom babel-preset-react
$ webpack

Note:

If you are using ES2015, you will want to also use the babel-preset-es2015 package.

Note: by default, React will be in development mode, which is slower, and not advised for production. To use React in production mode, set the environment variable NODE_ENV to production (using envify or webpack's DefinePlugin). For example:

new webpack.DefinePlugin({
  "process.env": {
    NODE_ENV: JSON.stringify("production")
  }
});

Quick Start Without npm #

If you're not ready to use npm yet, you can download the starter kit which includes prebuilt copies of React and React DOM.

Download Starter Kit 0.14.8

In the root directory of the starter kit, create a helloworld.html with the following contents.

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>Hello React!</title>
    <script src="build/react.js"></script>
    <script src="build/react-dom.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.23/browser.min.js"></script>
  </head>
  <body>
    <div id="example"></div>
    <script type="text/babel">
      ReactDOM.render(
        <h1>Hello, world!</h1>,
        document.getElementById('example')
      );
    </script>
  </body>
</html>

The XML syntax inside of JavaScript is called JSX; check out the JSX syntax to learn more about it. In order to translate it to vanilla JavaScript we use <script type="text/babel"> and include Babel to actually perform the transformation in the browser. Open the html from a browser and you should already be able to see the greeting!

Separate File #

Your React JSX code can live in a separate file. Create the following src/helloworld.js.

ReactDOM.render(
  <h1>Hello, world!</h1>,
  document.getElementById('example')
);

Then reference it from helloworld.html:

<script type="text/babel" src="src/helloworld.js"></script>

Note that some browsers (Chrome, e.g.) will fail to load the file unless it's served via HTTP.

Offline Transform #

First install the Babel command-line tools (requires npm):

npm install --global babel-cli
npm install babel-preset-react

Then, translate your src/helloworld.js file to plain JavaScript:

babel --presets react src --watch --out-dir build

Note:

If you are using ES2015, you will want to also use the babel-preset-es2015 package.

The file build/helloworld.js is autogenerated whenever you make a change. Read the Babel CLI documentation for more advanced usage.

ReactDOM.render(
  React.createElement('h1', null, 'Hello, world!'),
  document.getElementById('example')
);

Update your HTML file as below:

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>Hello React!</title>
    <script src="build/react.js"></script>
    <script src="build/react-dom.js"></script>
    <!-- No need for Babel! -->
  </head>
  <body>
    <div id="example"></div>
    <script src="build/helloworld.js"></script>
  </body>
</html>

Next Steps #

Check out the tutorial and the other examples in the starter kit's examples directory to learn more.

We also have a wiki where the community contributes with workflows, UI-components, routing, data management etc.

Good luck, and welcome!