+
+Then add this block to the `package.json` file of your project:
+
+```js
+{
+ // ...
+ "eslintConfig": {
+ "extends": "react-app"
+ }
+}
+```
+
+Finally, you will need to install some packages *globally*:
+
+```sh
+npm install -g eslint-config-react-app@0.3.0 eslint@3.8.1 babel-eslint@7.0.0 eslint-plugin-react@6.4.1 eslint-plugin-import@2.0.1 eslint-plugin-jsx-a11y@2.2.3 eslint-plugin-flowtype@2.21.0
+```
+
+We recognize that this is suboptimal, but it is currently required due to the way we hide the ESLint dependency. The ESLint team is already [working on a solution to this](https://github.com/eslint/eslint/issues/3458) so this may become unnecessary in a couple of months.
+
+## Installing a Dependency
+
+The generated project includes React and ReactDOM as dependencies. It also includes a set of scripts used by Create React App as a development dependency. You may install other dependencies (for example, React Router) with `npm`:
+
+```
+npm install --save +While you can still use `require()` and `module.exports`, we encourage you to use [`import` and `export`](http://exploringjs.com/es6/ch_modules.html) instead. + +For example: + +### `Button.js` + +```js +import React, { Component } from 'react'; + +class Button extends Component { + render() { + // ... + } +} + +export default Button; // Don’t forget to use export default! +``` + +### `DangerButton.js` + + +```js +import React, { Component } from 'react'; +import Button from './Button'; // Import a component from another file + +class DangerButton extends Component { + render() { + return ; + } +} + +export default DangerButton; +``` + +Be aware of the [difference between default and named exports](http://stackoverflow.com/questions/36795819/react-native-es-6-when-should-i-use-curly-braces-for-import/36796281#36796281). It is a common source of mistakes. + +We suggest that you stick to using default imports and exports when a module only exports a single thing (for example, a component). That’s what you get when you use `export default Button` and `import Button from './Button'`. + +Named exports are useful for utility modules that export several functions. A module may have at most one default export and as many named exports as you like. + +Learn more about ES6 modules: + +* [When to use the curly braces?](http://stackoverflow.com/questions/36795819/react-native-es-6-when-should-i-use-curly-braces-for-import/36796281#36796281) +* [Exploring ES6: Modules](http://exploringjs.com/es6/ch_modules.html) +* [Understanding ES6: Modules](https://leanpub.com/understandinges6/read#leanpub-auto-encapsulating-code-with-modules) + +## Adding a Stylesheet + +This project setup uses [Webpack](https://webpack.github.io/) for handling all assets. Webpack offers a custom way of “extending” the concept of `import` beyond JavaScript. To express that a JavaScript file depends on a CSS file, you need to **import the CSS from the JavaScript file**: + +### `Button.css` + +```css +.Button { + padding: 20px; +} +``` + +### `Button.js` + +```js +import React, { Component } from 'react'; +import './Button.css'; // Tell Webpack that Button.js uses these styles + +class Button extends Component { + render() { + // You can use them as regular CSS styles + return ; + } +} +``` + +**This is not required for React** but many people find this feature convenient. You can read about the benefits of this approach [here](https://medium.com/seek-ui-engineering/block-element-modifying-your-javascript-components-d7f99fcab52b). However you should be aware that this makes your code less portable to other build tools and environments than Webpack. + +In development, expressing dependencies this way allows your styles to be reloaded on the fly as you edit them. In production, all CSS files will be concatenated into a single minified `.css` file in the build output. + +If you are concerned about using Webpack-specific semantics, you can put all your CSS right into `src/index.css`. It would still be imported from `src/index.js`, but you could always remove that import if you later migrate to a different build tool. + +## Post-Processing CSS + +This project setup minifies your CSS and adds vendor prefixes to it automatically through [Autoprefixer](https://github.com/postcss/autoprefixer) so you don’t need to worry about it. + +For example, this: + +```css +.App { + display: flex; + flex-direction: row; + align-items: center; +} +``` + +becomes this: + +```css +.App { + display: -webkit-box; + display: -ms-flexbox; + display: flex; + -webkit-box-orient: horizontal; + -webkit-box-direction: normal; + -ms-flex-direction: row; + flex-direction: row; + -webkit-box-align: center; + -ms-flex-align: center; + align-items: center; +} +``` + +There is currently no support for preprocessors such as Less, or for sharing variables across CSS files. + +## Adding Images and Fonts + +With Webpack, using static assets like images and fonts works similarly to CSS. + +You can **`import` an image right in a JavaScript module**. This tells Webpack to include that image in the bundle. Unlike CSS imports, importing an image or a font gives you a string value. This value is the final image path you can reference in your code. + +Here is an example: + +```js +import React from 'react'; +import logo from './logo.png'; // Tell Webpack this JS file uses this image + +console.log(logo); // /logo.84287d09.png + +function Header() { + // Import result is the URL of your image + return
+An alternative way of handling static assets is described in the next section. + +## Using the `public` Folder + +>Note: this feature is available with `react-scripts@0.5.0` and higher. + +Normally we encourage you to `import` assets in JavaScript files as described above. This mechanism provides a number of benefits: + +* Scripts and stylesheets get minified and bundled together to avoid extra network requests. +* Missing files cause compilation errors instead of 404 errors for your users. +* Result filenames include content hashes so you don’t need to worry about browsers caching their old versions. + +However there is an **escape hatch** that you can use to add an asset outside of the module system. + +If you put a file into the `public` folder, it will **not** be processed by Webpack. Instead it will be copied into the build folder untouched. To reference assets in the `public` folder, you need to use a special variable called `PUBLIC_URL`. + +Inside `index.html`, you can use it like this: + +```html + +``` + +Only files inside the `public` folder will be accessible by `%PUBLIC_URL%` prefix. If you need to use a file from `src` or `node_modules`, you’ll have to copy it there to explicitly specify your intention to make this file a part of the build. + +When you run `npm run build`, Create React App will substitute `%PUBLIC_URL%` with a correct absolute path so your project works even if you use client-side routing or host it at a non-root URL. + +In JavaScript code, you can use `process.env.PUBLIC_URL` for similar purposes: + +```js +render() { + // Note: this is an escape hatch and should be used sparingly! + // Normally we recommend using `import` for getting asset URLs + // as described in “Adding Images and Fonts” above this section. + return