Yarn是Facebook发布的一款依赖管理工具，它比npm更快、更高效。
与NPM命令对照
npm install => yarn install
npm install --save [package] => yarn add [package]
npm install --save-dev [package] => yarn add [package] --dev
npm install --global [package] => yarn global add [package]
npm uninstall --save [package] => yarn remove [package]
npm uninstall --save-dev [package] => yarn remove [package]