webpack 制作一个模块热替换的web-server

webpack 基于node，开发需要开发的效率。‘热更替’显然是一种非常高效的方式，更加适合前端提升工作的效率。

webpack 中文文档 | webpack 中文网:https://www.webpackjs.com/guides/
目录结构：

package.json就像它的名字一样 用作 依赖管理

{
  "name": "webproject",
  "version": "1.0.0",
  "description": "",
  "private": true,
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "build": "webpack",
    "start": "webpack-dev-server --open",
    "watch": "webpack --watch"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "clean-webpack-plugin": "^0.1.19",
    "css-loader": "^1.0.0",
    "csv-loader": "^3.0.2",
    "file-loader": "^1.1.11",
    "html-webpack-plugin": "^3.2.0",
    "style-loader": "^0.22.1",
    "webpack": "^4.16.5",
    "webpack-cli": "^3.1.0",
    "webpack-dev-server": "^3.1.5",
    "xml-loader": "^1.2.1"
  },
  "dependencies": {
    "lodash": "^4.17.10"
  }
}

webpack.config.js webpack的配置文件，在文件里面可以设置文件的编译方式，文件入口，文件出口。（即文件的来源，文件的输出）

const path = require('path');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const CleanWebpackPlugin = require('clean-webpack-plugin');

module.exports = {
    entry: {
        app:'./src/index.js',
        print:'./src/print.js'
    },
    devServer: {
        contentBase: './dist'
    },
    plugins: [
        new CleanWebpackPlugin(['dist']),
        new HtmlWebpackPlugin({
            title: 'Output Management'
        })
    ],
    output: {
        filename: '[name].bundle.js',
        path: path.resolve(__dirname, 'dist')
    },
    module: {
        rules: [
            {
                test: /\.css$/,
                use: [
                    'style-loader',
                    'css-loader'
                ]
            },
            {
                test: /\.(png|svg|jpg|gif)$/,
                use: [
                    'file-loader'
                ]
            },
            {
                test: /\.(woff|woff2|eot|ttf|otf)$/,
                use: [
                    'file-loader'
                ]
            },
            {
                test: /\.(csv|tsv)$/,
                use: [
               'csv-loader'
                ]
             },
             {
                 test: /\.xml$/,
                 use: [
                 'xml-loader'
                ]
             }
        ]
    }
};