npm换源

查看当前源：

npm config get registry

默认源：

npm config set registry https://registry.npmjs.org

淘宝源：npm config set registry https://registry.npm.taobao.org

淘宝源（新）：

npm config set registry https://registry.npmmirror.com

单次指定源

npm --registry https://registry.npmmirror.com install