源：https://www.jianshu.com/p/748a65d4f7a5
查看源
npm config get registry // 或 npm config list
修改源
# 默認源 npm config set registry https://registry.npmjs.org # https -> http，這樣網速就會好很多 npm config set registry http://registry.npmjs.org # 如果還不能下載，就切換成淘寶源 npm config set registry https://registry.npm.taobao.org