webpack 启动服务，监听文件变化，自动更新

var {CleanWebpackPlugin} = require('clean-webpack-plugin');
var HtmlWebpackPlugin = require('html-webpack-plugin');
var Webpack = require('webpack');
module.exports = {
    entry:{
        index:'./src/index.js'
    },
    output:{
        path:__dirname,
        filename:'bundle.js'
    },
    module:{
        rules:[
            {
                test:/\.css$/,
                use:[
                    {loader:'style-loader'},
                    {loader:'css-loader'}
                ]
            }
        ]
    },
    plugins:[
        // new CleanWebpackPlugin(),
        new HtmlWebpackPlugin({
            template:'./src/index.html'
        }),
        new Webpack.HotModuleReplacementPlugin()
    ],
    devServer:{
        port:'9091',
        contentBase:'dist',
        hot:true
    },
    mode:'development'
}

　　

{
  "name": "js",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "jquery": "^3.5.0"
  },
  "devDependencies": {
    "clean-webpack-plugin": "^3.0.0",
    "css-loader": "^3.5.2",
    "html-webpack-plugin": "^4.2.0",
    "style-loader": "^1.1.4",
    "webpack": "^4.42.1",
    "webpack-cli": "^3.3.11",
    "webpack-dev-server": "^3.10.3"
  }
}