yarn与npm

安装yarn
下载msi包
https://yarnpkg.com/lang/zh-hans/docs/install/#windows-stable

命令行执行
运行命令来测试 Yarn 是否安装：
yarn --version

yarn命令安装

npm、yarn安装步骤

npm	yarn
npm install	yarn
npm install react --save	yarn add react
npm uninstall react --save	yarn remove react
npm install react --save-dev	yarn add react --dev
npm update --save	yarn upgrade

git clone xxx
npm install
npm run dev

git clone xxx
yarn
yarn start