（二）webpack run server配置

1.安装 webpack-dev-server

2.配置package.json "dev":"webpack-dev-server --config webpack.config.js"

3.配置编译目标,在webpack.config.js中补充target:'web'

4.根据不同的环境判断(开发环境/正式环境) 安装cross-env

运行环境存储在process.env中

5.在package.json中,利用corss-env判断环境.

判断环境

"build": "cross-env NODE_ENV=production webpack --config webpack.config.js",

"dev": "cross-env NODE_ENV=development webpack-dev-server --config webpack.config.js"

6.在webpack.config.js写判断逻辑

7.js需要加载到一个html里面运行,利用html-webpack-plugin 安装它