-
-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