React has been designed from the start for gradual adoption, and you can use as little or as much React as you need.

The majority of websites aren’t, and don’t need to be, single-page apps. With a few lines of code and no build tooling, try React in a small part of your website. You can then either gradually expand its presence, or keep it contained to a few dynamic widgets.

Add React in One Minute

how to add a React component to an existing HTML page. You can follow along with your own website, or create an empty HTML file to practice.

There will be no complicated tools or install requirements — to complete this section, you only need an internet connection, and a minute of your time.

Step 1: Add a DOM Container to the HTML

First, open the HTML page you want to edit. Add an empty <div> tag to mark the spot where you want to display something with React. For example:

<!-- ... existing HTML ... -->

<div id="like_button_container"></div>

<!-- ... existing HTML ... -->

Tip

You can place a “container” <div> like this anywhereinside the <body> tag. You may have as many independent DOM containers on one page as you need. They are usually empty — React will replace any existing content inside DOM containers.

Step 2: Add the Script Tags

Next, add three <script> tags to the HTML page right before the closing </body> tag:

<!-- ... other HTML ... -->

  <!-- Load React. -->

  <!-- Note: when deploying, replace "development.js" with "production.min.js". -->

  <script src="https://unpkg.com/react@16/umd/react.development.js" crossorigin></script>

  <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js" crossorigin></script>

  <!-- Load our React component. -->

  <script src="like_button.js"></script>

</body>

The first two tags load React. The third one will load your component code.

Step 3: Create a React Component

Create a file called like_button.js next to your HTML page.

Open this starter code and paste it into the file you created.

'use strict';

const e = React.createElement;

class LikeButton extends React.Component {

  constructor(props) {

    super(props);

    this.state = { liked: false };

  }

  render() {

    if (this.state.liked) {

      return 'You liked this.';

    }

    return e(

      'button',

      { onClick: () => this.setState({ liked: true }) },

      'Like'

    );

  }

}

Tip

This code defines a React component called LikeButton. Don’t worry if you don’t understand it yet — we’ll cover the building blocks of React later in our hands-on tutorial and main concepts guide. For now, let’s just get it showing on the screen!

After the starter code, add two lines to the bottom of like_button.js:

// ... the starter code you pasted ...

const domContainer = document.querySelector('#like_button_container');

ReactDOM.render(e(LikeButton), domContainer);

These two lines of code find the <div> we added to our HTML in the first step, and then display our “Like” button React component inside of it.

Tip: Reuse a Component

Commonly, you might want to display React components in multiple places on the HTML page. Here is an example that displays the “Like” button three times and passes some data to it:

View the full example source code

Note

This strategy is mostly useful while React-powered parts of the page are isolated from each other. Inside React code, it’s easier to use component compositioninstead.

Tip: Minify JavaScript for Production

Before deploying your website to production, be mindful that unminified JavaScript can significantly slow down the page for your users.

If you already minify the application scripts, your site will be production-ready if you ensure that the deployed HTML loads the versions of React ending in production.min.js:

<script src="https://unpkg.com/react@16/umd/react.production.min.js" crossorigin></script>

<script src="https://unpkg.com/react-dom@16/umd/react-dom.production.min.js" crossorigin></script>

If you don’t have a minification step for your scripts, here’s one way to set it up.

Optional: Try React with JSX

In the examples above, we only relied on features that are natively supported by the browsers. This is why we used a JavaScript function call to tell React what to display:

const e = React.createElement;

// Display a "Like" <button>

return e(

  'button',

  { onClick: () => this.setState({ liked: true }) },

  'Like'

);

However, React also offers an option to use JSX instead:

// Display a "Like" <button>

return (

  <button onClick={() => this.setState({ liked: true })}>

    Like

  </button>

);

These two code snippets are equivalent. While JSX is completely optional, many people find it helpful for writing UI code — both with React and with other libraries.

You can play with JSX using this online converter.

Quickly Try JSX

The quickest way to try JSX in your project is to add this <script> tag to your page:

<script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>

Now you can use JSX in any <script> tag by adding type="text/babel" attribute to it. Here is an example HTML file with JSX that you can download and play with.

This approach is fine for learning and creating simple demos. However, it makes your website slow and isn’t suitable for production. When you’re ready to move forward, remove this new <script> tag and the type="text/babel" attributes you’ve added. Instead, in the next section you will set up a JSX preprocessor to convert all your <script> tags automatically.

Add JSX to a Project

Adding JSX to a project doesn’t require complicated tools like a bundler or a development server. Essentially, adding JSX is a lot like adding a CSS preprocessor. The only requirement is to have Node.js installed on your computer.

Go to your project folder in the terminal, and paste these two commands:

Step 1: Run npm init -y (if it fails, here’s a fix)
Step 2: Run npm install babel-cli@6 babel-preset-react-app@3

Tip

We’re using npm here only to install the JSX preprocessor; you won’t need it for anything else. Both React and the application code can stay as <script> tags with no changes.

Congratulations! You just added a production-ready JSX setup to your project.

Run JSX Preprocessor

Create a folder called src and run this terminal command:

npx babel --watch src --out-dir . --presets react-app/prod

Note

npx is not a typo — it’s a package runner tool that comes with npm 5.2+.

If you see an error message saying “You have mistakenly installed the babel package”, you might have missed the previous step. Perform it in the same folder, and then try again.

Don’t wait for it to finish — this command starts an automated watcher for JSX.

If you now create a file called src/like_button.js with this JSX starter code, the watcher will create a preprocessed like_button.js with the plain JavaScript code suitable for the browser. When you edit the source file with JSX, the transform will re-run automatically.

As a bonus, this also lets you use modern JavaScript syntax features like classes without worrying about breaking older browsers. The tool we just used is called Babel, and you can learn more about it from its documentation.

React Without JSX

JSX is not a requirement for using React. Using React without JSX is especially convenient when you don’t want to set up compilation in your build environment.

Each JSX element is just syntactic sugar for calling React.createElement(component, props, ...children). So, anything you can do with JSX can also be done with just plain JavaScript.

For example, this code written with JSX:

class Hello extends React.Component {

  render() {

    return <div>Hello {this.props.toWhat}</div>;

  }

}

ReactDOM.render(

  <Hello toWhat="World" />,

  document.getElementById('root')

);

can be compiled to this code that does not use JSX:

class Hello extends React.Component {

  render() {

    return React.createElement('div', null, `Hello ${this.props.toWhat}`);

  }

}

ReactDOM.render(

  React.createElement(Hello, {toWhat: 'World'}, null),

  document.getElementById('root')

);

If you’re curious to see more examples of how JSX is converted to JavaScript, you can try out the online Babel compiler.

The component can either be provided as a string, or as a subclass of React.Component, or a plain function for stateless components.

If you get tired of typing React.createElement so much, one common pattern is to assign a shorthand:

const e = React.createElement;

ReactDOM.render(

  e('div', null, 'Hello World'),

  document.getElementById('root')

);

If you use this shorthand form for React.createElement, it can be almost as convenient to use React without JSX.

Alternatively, you can refer to community projects such as react-hyperscript and hyperscript-helpers which offer a terser syntax.

React——嵌入已有项目 && jsx的更多相关文章

React Native 在现有项目中的探路
移动开发中,native开发性能和效果上无疑是最好的. 但是在众多的情况下,native开发并不是最优的选择.当需求经常改动的时候,当预算有限的时候,当deadline很近的时候,native开发的成 ...
【前端】一步一步使用webpack+react+scss脚手架重构项目
前言前几天做了一个项目:[node]记录项目的开始与完成——pipeline_kafka流式数据库管理项目:因为开发时间紧迫,浅略的使用了一下react,感觉这个ui库非常的符合我的口味,现在趁着有 ...
一步一步使用webpack+react+scss脚手架重构项目
前几天做了一个项目:[node]记录项目的开始与完成——pipeline_kafka流式数据库管理项目:因为开发时间紧迫,浅略的使用了一下react,感觉这个ui库非常的符合我的口味,现在趁着有空闲时 ...
React Native 系列(三) -- 项目结构介绍
前言本系列是基于React Native版本号0.44.3写的,相信大家看了本系列前面两篇文章之后,对于React Native的代码应该能看懂一点点了吧.本篇文章将带着大家来认识一下React N ...
iOS-Cordova集成开发，已有项目集成cordova
iOS-Cordova集成开发,已有项目集成cordova 项目组准备开发一个APP,要求Android和iOS端页面完全一致,除了一个页面跟业务相关的不同,其他界面基本一致,因此,萌生一个想法,关于 ...
React.js学习之理解JSX和组件
在开启JSX的学习旅程前,我们先了解一下React的基本原理.React本质上是一个"状态机",它只关心两件事:更新DOM和响应事件,React不处理Ajax.路由和数据存储,也不 ...
AntDesign-React与VUE有点不一样，第一篇深入了解React的概念之一：JSX
AntDesign-React与VUE有点不一样,第一篇深入了解React的概念之一:JSX 一.什么是JSX 使用JSX声明一个变量(REACT当中的元素): const element =< ...
Git-将已有的项目提交到Git
准备工作:1. 安装Githttp://git-scm.com/download/2.申请一个GitHub或者coding账号(coding为国产,不需FQ呦.两者方法基本相同,本文以coding为例 ...
将已有项目提交到github/从github上pull到本地
去自己的工作分支$ git checkout work 工作.... 提交工作分支的修改$ git commit -a 回到主分支$ git checkout master 获取远程最新的修改,此时不 ...

随机推荐

element-ui upload组件 onchange事件传自定义参数
<el-upload class="upload-demo" list-type="picture" accept=" ...
前端学习笔记--CSS样式--列表和表格
1.列表 2.表格 odd:奇数 even:偶数
Listener中@Autowired无法注入的问题
最近在用监听器的时候遇到了spring无法注入的问题,代码如下,这个task总是null,包明明已经被扫到了,就是注入不进来. public class MyListener implements S ...
Hive和HBase的区别转载：https://www.cnblogs.com/guoruibing/articles/9894521.html
1.Hive和HBase的区别 1)hive是sql语言,通过数据库的方式来操作hdfs文件系统,为了简化编程,底层计算方式为mapreduce. 2)hive是面向行存储的数据库. 3)Hive本身 ...
获取历史K线数据的几个方法
1.通过已有的股票交易软件下载数据,如果他们是开源结构的,就可以解析他们的K线数据. 2.在互联网上抓取数据 int iStockCode;CString strUrl; 通过OpenUrl.Read ...
Laravel - 解决连接MySQL时报"The server requested authentication method unknown to the client”错误
2019-04-12发布:hangge阅读:934 1,问题描述最近建了个 Laravel 项目,当配置好 MySQL 数据库进行请求时,页面报如下错误: SQLSTATE[HY000] [ ...
MySQL 计算时间差函数 TIMESTAMPDIFF、DATEDIFF
一.TIMESTAMPDIFF 支持天.小时.秒等 selet TIMESTAMPDIFF(hour,odl_time,now()); 计算old_time与现在时间的小时差. 二.DATEDIFF ...
西门子二次开发--HMI failed to start
一.Sinumerik二次开发错误:HMI failed to start. HMI--SL Framework reported error: GUI Component could not be ...
luogu P3567 [POI2014]KUR-Couriers
二次联通门 : luogu P3567 [POI2014]KUR-Couriers MMP 指针 RE + MLE + WA..... 不得已...向黑恶的数组实力低头 /* 指针 */ #inclu ...
Word 有哪些神奇的功能？
作者:秦阳链接:https://www.zhihu.com/question/27035859/answer/621742048来源:知乎著作权归作者所有.商业转载请联系作者获得授权,非商业转载请注明 ...

React——嵌入已有项目 && jsx