yarn安装依赖遇到error An unexpected error occurred: "registry.yarnpkg.com/react: con...这种错误，这是网络超时，配置淘宝镜像即可。
yarn 设置为 淘宝源
yarn config set registry https://registry.npm.taobao.org --global
yarn config set disturl https://npm.taobao.org/dist --global
npm 设置为 淘宝源
npm config set registry https://registry.npm.taobao.org
npm config set disturl https://npm.taobao.org/dist
项目中如果用的是 sass，需要下载 node-sass，这个依赖包下载是相当的慢，可以单独设置源地址
yarn config set sass-binary-site http://npm.taobao.org/mirrors/node-sass
npm config set sass-binary-site http://npm.taobao.org/mirrors/node-sass
最后删除 node_modules，重新下载就行了
