捆绑JS中需要未定义的错误反应js答案

【问题标题】：require not defined error on bundled JS reactjs捆绑JS中需要未定义的错误反应js
【发布时间】：2016-07-15 10:38:57
【问题描述】：

我是 Django 和 ReactJS 的新手，正在尝试使用本教程将简单的 JSX 代码编译为 JS：http://geezhawk.github.io/2016/02/02/using-react-with-django-rest-framework.html 没用，所以我使用npm run dev 编译，现在它可以工作但在浏览器控制台中出现错误：未捕获的ReferenceError：未定义反应这是我的 webpack.config.js

    var path = require('path');
var webpack = require('webpack');
var BundleTracker = require('webpack-bundle-tracker');
var nodeExternals = require('webpack-node-externals');


module.exports = {
    //the base directory (absolute path) for resolving the entry option
    context: __dirname,
    //the entry point we created earlier. Note that './' means
    //your current directory. You don't have to specify the extension  now,
    //because you will specify extensions later in the `resolve` section
    entry: './assets/js/index',

    output: {
        //where you want your compiled bundle to be stored
        path: path.resolve('./assets/bundles/'),
        //naming convention webpack should use for your files
        filename: '[name]-[hash].js',
    },
    target: 'node', // in order to ignore built-in modules like path, fs, etc.
    externals: {
    react: 'react'
}, // in order to ignore all modules in node_modules folder

    plugins: [
        //tells webpack where to store data about your bundles.
        new BundleTracker({filename: './webpack-stats.json'}),
        //makes jQuery available in every module
        new webpack.ProvidePlugin({
            //React: "react",
            $: 'jquery',
            jQuery: 'jquery',
            'window.jQuery': 'jquery'
        })
    ],

    module: {
        loaders: [
            //a regexp that tells webpack use the following loaders on all
            //.js and .jsx files
            {test: /\.jsx?$/,
                //we definitely don't want babel to transpile all the files in
                //node_modules. That would take a long time.
                /*exclude: /node_modules/,*/
                //use the babel loader
                loader: 'babel-loader',
                query: {
                    //specify that we will be dealing with React code
                    presets: ['react']
                }
            }
        ]
    },

    resolve: {
        //tells webpack where to look for modules
        modulesDirectories: ['node_modules'],
        //extensions that should be used to resolve modules
        extensions: ['', '.js', '.jsx']
     }
    }

还有 assets/bundles/index.js

    var React = require('react')
    var ReactDOM = require('react-dom')
    //snaha//
    var BooksList = React.createClass({
    loadBooksFromServer: function(){
        console.log(123454657);
        $.ajax({
            url: this.props.url,
            datatype: 'json',
            cache: false,
            success: function(data) {
                this.setState({data: data});
            }.bind(this)
        })
    },

    getInitialState: function() {
        return {data: []};
    },

    componentDidMount: function() {
        this.loadBooksFromServer();
        setInterval(this.loadBooksFromServer,
                    this.props.pollInterval)
    },
    render: function() {
        if (this.state.data) {
            console.log('DATA!')
            var bookNodes = this.state.data.map(function(book){
                return <li> {book.title} </li>
            })
        }
        return (
            <div>
                <h1>Hello React!</h1>
                <ul>
                    {bookNodes}
                </ul>
            </div>
        )
      }
   })

     ReactDOM.render(<BooksList url='/api/' pollInterval={1000} />,
    document.getElementById('container'))

还有templates/body.html

    {% load render_bundle from webpack_loader %}
    <!doctype html>
    <html>
    <head>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.7/react-with-addons.js"></script>
   <script src="https://cdnjs.cloudflare.com/ajax/libs/react/0.14.7/react-dom.js"></script>
     <meta charset="UTF-8">
     <title>Hello React
        {% block content %}
            {{ id }}
        {% endblock %}
     </title>
      </head>
      <body>
     <div id="container"></div>
      {% render_bundle 'main' %}
      </body>
      </html>

我缺少什么吗？ here is my Django project structure

【问题讨论】：

标签： javascript django reactjs npm react-jsx

【解决方案1】：

我终于解决了！问题是：它试图在浏览器上的 React.js 提供变量 React 的地方获得变量反应！所以我简单地将 webpack.config.js 的外部更改为

    externals: {
    React: 'react'
},

解决了问题！

面临的下一个问题：

“未定义进程”

解决方案：添加

var env = process.env.WEBPACK_ENV;

到 webpack.config.js 的顶部和

new webpack.DefinePlugin({
  'process.env.NODE_ENV': '"production"'
}),
     new webpack.DefinePlugin({
  'process.env': {
    'NODE_ENV': '"production"'
  }
})

进入model.export的插件部分

所以最终的 webpack.config.js 将是：

    var path = require('path');
var webpack = require('webpack');
var BundleTracker = require('webpack-bundle-tracker');
var nodeExternals = require('webpack-node-externals');
var env = process.env.WEBPACK_ENV;


module.exports = {
    //the base directory (absolute path) for resolving the entry option
    context: __dirname,
    //the entry point we created earlier. Note that './' means
    //your current directory. You don't have to specify the extension  now,
    //because you will specify extensions later in the `resolve` section
    entry: './assets/js/index',

    output: {
        //where you want your compiled bundle to be stored
        path: path.resolve('./assets/bundles/'),
        //naming convention webpack should use for your files
        filename: '[name]-[hash].js',
    },
    target: 'node', // in order to ignore built-in modules like path, fs, etc.
    externals: {
    React: 'react'
}, // in order to ignore all modules in node_modules folder

    plugins: [
        //tells webpack where to store data about your bundles.
        new BundleTracker({filename: './webpack-stats.json'}),
        //makes jQuery available in every module
        new webpack.ProvidePlugin({
            //React: "react",
            $: 'jquery',
            jQuery: 'jquery',
            'window.jQuery': 'jquery'
        }),
         new webpack.DefinePlugin({
      'process.env.NODE_ENV': '"production"'
    }),
         new webpack.DefinePlugin({
      'process.env': {
        'NODE_ENV': '"production"'
      }
    })
    ],

    module: {
        loaders: [
            //a regexp that tells webpack use the following loaders on all
            //.js and .jsx files
            {test: /\.jsx?$/,
                //we definitely don't want babel to transpile all the files in
                //node_modules. That would take a long time.
                /*exclude: /node_modules/,*/
                //use the babel loader
                loader: 'babel-loader',
                query: {
                    //specify that we will be dealing with React code
                    presets: ['react']
                }
            }
        ]
    },

    resolve: {
        //tells webpack where to look for modules
        modulesDirectories: ['node_modules'],
        //extensions that should be used to resolve modules
        extensions: ['', '.js', '.jsx']
    }
}

现在享受 React！快乐编码:-)

【讨论】：

天哪，这是一次痛苦的经历...颠倒 externals 属性的顺序也解决了我的 module not defined 问题，当通过 <script> 单独加载库时

【解决方案2】：

你能看看你是否安装了所有的要求。

查看 package.json。如果您确实运行，您应该已经在需求中注明了反应。

npm install

如果没有，请运行

npm install react --save

ps：在我的选项中，如果您正在运行 Webpack，请尝试将 babel 添加到 Webpack 预设并在 ES2015 规范中编写 javascript。

【讨论】：

是的，npm 在那里，react 也在那里。你能给我一份关于weback、babel、es2015等的清晰文档吗？目前我对所有这些都不干净。