问题:

Cannot load gulp: Error: Node Sass does not yet support your current environment: Windows 64-bit with Unsupported runtime (57)
For more information on which environments are supported please see:
https://github.com/sass/node-sass/releases/tag/v3.13.1
[09:57:14] Cannot run sass task: missing in gulpfile.js

解决方法:

cnpm install node-sass