79 lines
2.8 KiB
Markdown
79 lines
2.8 KiB
Markdown
---
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title: Your first React App
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---
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## Your first React App
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### Installation
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As specified in the previous artice (Installation), run the `Create React App` tool. After everything has finished, `cd` into the folder of your application and run `npm start`.
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This will start a development server and you are all set to start developing your app!
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- For node version 5.2+
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```bash
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npx create-react-app my-app
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cd my-first-app
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npm start
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```
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- For node versions below 5
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```bash
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npm install -g create-react-app
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create-react-app my-first-app
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cd my-first-app
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npm start
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```
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### Editing the code
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Start up your editor or IDE of choice and edit the `App.js` file in the `src` folder. When created with the `react-create-app` tool, there will already be some code in this file.
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The code will consist of these parts:
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#### Imports
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```JavaScript
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import React, { Component } from 'react';
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import logo from './logo.svg';
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import './App.css';
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```
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This is used by [webpack](https://webpack.js.org/) to import all required modules so that your code can use them. This code imports 3 modules:
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1) `React` and `Component`, which allow us to use React as it should be used. (With components)
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2) `logo`, which allows us to use `logo.svg` in this file.
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3) `./App.css`, which imports the stylesheet for this file.
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#### Classes/Components
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```JavaScript
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class App extends Component {
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render() {
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return (
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<div className="App">
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<header className="App-header">
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<img src={logo} className="App-logo" alt="logo" />
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<h1 className="App-title">Welcome to React</h1>
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</header>
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<p className="App-intro">
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To get started, edit <code>src/App.js</code> and save to reload.
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</p>
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</div>
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);
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}
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}
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```
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React is a library that makes use of Components, which let you split up your UI into independent, reusable pieces, and think about each piece in isolation.
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There is already 1 component created, the `App` component. If you used the `create-react-app` tool, this component is the main component in the project and you should build around this central class.
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We will look at components more detailed in next chapters.
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#### Exports
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When creating a class in react, you should export them after declaration, which allows you to use the component in another file by using the `import` keyword. You can use `default` after the `export` keyword to tell React that this is the main class of this file.
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```JavaScript
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export default App;
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```
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### View the results!
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When you've started the development server by issuing the `npm start` command, you can view the changes you add to your project live in your browser. After issuing the command, npm should open a browser automatically displaying your app.
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### Sources
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[1. React documentation](https://reactjs.org/docs/hello-world.html)
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