上学时期安装过node.js安装失败之后就没再弄，现在做项目又安装了一次出现问题
npm ERR! code ETIMEDOUT
npm ERR! syscall connect
npm ERR! errno ETIMEDOUT
npm ERR! network request to https://registry.npmjs.org/express failed, reason: connect ETIMEDOUT 104.16.27.34:443
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'
安装教程：nodejs安装和环境配置-Windows_nodejs安装及环境配置win7-CSDN博客
进行至 测试效果：
全局安装最常用的 express 模块 进行测试
命令如下:npm install express -g
出现上述错误，像是网络连接问题，从网上搜索大致步骤为：
1.清除缓存
npm config set proxy false
npm config set proxy false
2.如果报错，继续强制清除
npm cache clean --force
之后返回原来的安装步骤继续
YARN安装 注意路径不要带有空格名
