1、安装：
cnpm i webpack-dev-server -D
2、package.json中配置命令：
"dev": "webpack-dev-server --open chrome --port 3000 --hot --host 127.0.0.1"{
"name": "wp4-1",
"version": "1.0.0",
"description": "", "main": "index.js", "scripts": { "test": "echo \"Error: no test specified\" && exit 1", "dev": "webpack-dev-server --open chrome --port 3000 --hot --host 127.0.0.1" }, "keywords": [], "author": "", "license": "ISC", "devDependencies": { "webpack": "^4.41.5", "webpack-cli": "^3.3.10", "webpack-dev-server": "^3.10.1" } } 3、运行命令打包“npm run dev”
说明：webpack-dev-server实时打包好的main.js是托管在内存中，所以在项目根目录中看不到，但是我们可以认为在项目根目录中有一个看不见的main.js。
4、http://127.0.0.1:3000/src/预览index.html文件：
<!DOCTYPE html>
<html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> <script src="../main.js"></script> </head> <body> <h1>首页</h1> </body> </html>