安装node-sass及报错后解决方案

使用npm install 命令安装node-sass时，经常出现安装失败的情况。原因在于npm服务器在美国，还有就是某强大的防火墙作用。导致模块无法下载。

1 npm install node-sass                                                      

1 Cannot download https://github.com/sass/node-sass/releases/download/v3.4.2/win32-x64-46_binding.node
2 
3 Hint: If github.com is not accessible in your location
4 try setting a proxy via HTTP_PROXY, e.g. 
5 export HTTP_PROXY=http://example.com:1234
6 or configure npm proxy via
7 npm config set proxy http://example.com:8080'

解决方法：
1、使用淘宝镜像完成安装。

1 npm install -g cnpm --registry=https://registry.npm.taobao.org
2 cnpm install node-sass

在安装node-sass之后，重新运行会报如下错误

ERROR Failed to compile with 1 errors 16:47:39

This dependency was not found:

* !!vue-style-loader!css-loader?{"sourceMap":true}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":true,"id":"data-v-742a2c37","scoped":true,"has
InlineConfig":false}!sass-loader?{"sourceMap":true}!../../node_modules/vue-loader/lib/selector?type=styles&index=0!./signInBg.vue in ./src/components/signInBg.
vue

To install it, you can run: npm install --save !!vue-style-loader!css-loader?{"sourceMap":true}!../../node_modules/vue-loader/lib/style-compiler/index?{"vue":t
rue,"id":"data-v-742a2c37","scoped":true,"hasInlineConfig":false}!sass-loader?{"sourceMap":true}!../../node_modules/vue-loader/lib/selector?type=styles&index=0
!./signInBg.vue

解决思路：

1. npm install sass-loader --save;

2. npm install node-sass --save;

然后运行npm run dev就可以