Build Action to
None. That won't work on an entire folders however, sigh...
Since Visual Studio doesn't provide us such option, the solution is basically to open your .csproj file with your preferred editor and to replace all occurrences of
<Content Include="frontend\snip\snip\somefile.js" />with
<None Include="frontend\snip\snip\somefile.js" />I'll leave the regex for you ;).
I just did it with Sublime Text and that's just amazing. Basically you do a
Ctrl+Fand enter your regex. Then you click the "Find All" button and it will place a cursor automatically on all of the found occurrences such that you can just edit those lines. Awesome!!