在vue文件中，要引入相應的樣式，經常會用到
@import "~common/stylus/mixin"這種寫法，為什麼會用到~？查看了stylus-loader文檔，發現這句話

 It also lets you load a stylus file from a package installed in node_modules or if you add a modulesDirectories, like modulesDirectories: ['node_modules', 'web_modules', 'bower_components'] option you could load from a folder like bower_components. To load files from a relative path leave off the ~ and @import 'relative-styles/my-styles'; it.

結合本人做的測試，發現這個~和webpack配置文件中alias有關，只有在webpack配置文件中配置了alias，設置了相應的別名路徑，@import才能通過~別名來實現查找相應的文件。