Auto compile with Mix

Hello everyone! I was wondering if there is anyway of compiling all of the files within a folder.

What I mean by this, instead of typing

mix.js('resources/assets/js/app.js', 'public/js')
   .sass('resources/assets/sass/app.scss', 'public/css');

Is there a way of typing.... something like...

mix.js('resources/assets/js/', 'public/js')
   .sass('resources/assets/sass/', 'public/css');

So that it will compile all of the files within each folder, so if you were to make another file, it will already compile it without you having to add another mix parameter.