Mac环境部署告一段落，同事多次建议为什么不用yarn。STF本身也包含了yarn.lock文件。简单学习一下yarn 的相关内容。
Yarn is a package manager for your code. Code is shared through something called a package (sometimes referred to as a module). A package contains all the code being shared as well as a
package.jsonfile which describes the package.
不建议使用brew install yarn brew会自动安装最新的node依赖（目前为node12版本），但其实我们只需要yarn而已。
使用shell脚本安装
curl -o- -L https://yarnpkg.com/install.sh | bash
Normal dependencies are usually installed from the npm registry.
所以yarn也是使用npm的registry。
yarn --version
# 根据package.json文件进行全量安装
yarn install
yarn
- Adding a dependency
yarn add [package]
yarn add [package]@[version]
yarn add [package]@[tag]
- Add to devDependencies, peerDependencies, and optionalDependencies respectively:
yarn add [package] --dev
yarn add [package] --peer
yarn add [package] --optional
- Upgrading a dependency
yarn upgrade [package]
yarn upgrade [package]@[version]
yarn upgrade [package]@[tag]
- Remove
yarn remove [package]