JSHint: Overwrite single .jshintrc option for whole folder
Yes, there's a feature in jshint v2.5.1 that is "extends", for your example this could be like this:
/.jshintrc
{ "smarttabs": true, "undef": true, "unused": true}
/server/.jshintrc
{ "extends": "../.jshintrc", "node": true}
/client/.jshintrc
{ "extends": "../.jshintrc", "browser": true}
You can read more about this feature here:https://github.com/jshint/jshint/releases/tag/2.5.1