package.json中main，module，exports三种方式的使用，自定义入口文件index.js

# package-v3-cli ## Project setup ``` npm install ``` ### Compiles and hot-reloads for development ``` npm run serve ``` ### Compiles and minifies for production ``` npm run build ``` ### Lints and fixes files ``` npm run lint ``` ### Customize configuration See [Configuration Reference](https://cli.vuejs.org/config/).