node-sass安装出错问题

npm install安装node-sass时出现以下问题

Cannot download https://github.com/sass/node-sass/releases/download/v4.5.3/win32-x64-46_binding.node

Hint: If github.com is not accessible in your location
try setting a proxy via HTTP_PROXY, e.g. 
export HTTP_PROXY=http://example.com:1234
or configure npm proxy via
npm config set proxy http://example.com:8080'

原因是node-sass被墙掉了，那我们用淘宝镜像cnpm安装：

npm install -g cnpm --registry=https://registry.npm.taobao.org