由于想用excel文件导入和导出微信小程序数据库内容，按照百度高人的指点，需要再云函数里先安装npm install node-xlsx但一致未成功，根本就卡住不动，然后提示如下：

PS D:\Private Files\微信小程序\拓领预约系统\拓领仓库预约系统1.1(+logs)\cloud> npm install node-xlsx

npm ERR! code ETIMEDOUT

npm ERR! errno ETIMEDOUT

npm ERR! network request to https://registry.npmjs.org/node-xlsx failed, reason: connect ETIMEDOUT 104.16.25.35:443

npm ERR! network This is a problem related to network connectivity.

npm ERR! network In most cases you are behind a proxy or have bad network settings.

npm ERR! network

npm ERR! network If you are behind a proxy, please make sure that the

npm ERR! network 'proxy' config is set properly.  See: 'npm help config'

npm ERR! A complete log of this run can be found in:

npm ERR!     C:\Users\jazhang\AppData\Roaming\npm-cache\_logs\2020-07-01T14_48_07_145Z-debug.log

我的问题是：

1. 以上原因是什么？我看大意是网络不好？
2. 按照此类xlsx依赖包，除了针对某一特定云函数安装依赖，还可以在哪里统一一次性安装依赖，如何操作？

请高人指定！感谢！