解決する

Module build failed: Error: ENOENT: no such file or directory, scandir 'E:\code\weChat\-web\node_modules\node-sass\vendor'
$ npm set registry https://registry.npm.taobao.org # Register module image
$ npm set disturl https://npm.taobao.org/dist # node-gyp compile dependent node source images

# # Add the following options
$ npm set chromedriver_cdnurl http://cdn.npm.taobao.org/dist/chromedriver # chromedriver binary package image
$ npm set operadriver_cdnurl http://cdn.npm.taobao.org/dist/operadriver # operadriver binary package image
$ npm set phantomjs_cdnurl http://cdn.npm.taobao.org/dist/phantomjs # phantomjs binary package image
$ npm set fse_binary_host_mirror https://npm.taobao.org/mirrors/fsevents # fsevents binary package
$ npm set sass_binary_site http://cdn.npm.taobao.org/dist/node-sass # node-sass binary package mirror
$ npm set electron_mirror http://cdn.npm.taobao.org/dist/electron/ # electron binary package mirror

npm rebuild node-sass

以下が順次インストールされます。

$ npm set registry https://registry.npm.taobao.org # Register module image
$ npm set disturl https://npm.taobao.org/dist # node-gyp compile dependent node source images

# # Add the following options
$ npm set chromedriver_cdnurl http://cdn.npm.taobao.org/dist/chromedriver # chromedriver binary package image
$ npm set operadriver_cdnurl http://cdn.npm.taobao.org/dist/operadriver # operadriver binary package image
$ npm set phantomjs_cdnurl http://cdn.npm.taobao.org/dist/phantomjs # phantomjs binary package image
$ npm set fse_binary_host_mirror https://npm.taobao.org/mirrors/fsevents # fsevents binary package
$ npm set sass_binary_site http://cdn.npm.taobao.org/dist/node-sass # node-sass binary package mirror
$ npm set electron_mirror http://cdn.npm.taobao.org/dist/electron/ # electron binary package mirror

うまくいかない場合

npm rebuild node-sass