Sample of using connect-assets (mincer/sprockets-style concatenation) without globals.

bundle.js

//= require closure_start
//= require jQuery
//= require the_rest_of_your_dependencies
//= require_self
//= require closure_end

var something = function () {
  return "this also gets included in the closure, since require_self is defined".
};

closure_end.js

})();

closure_start.js

(function () {