using a closure so middleware no longer requires currying

utilities.js

$.fn.setupFilterInput = function (events) {
  var $input = $(this),
    handlers = {
      // use these to provide default but overwriteable functionality
      focus: function () {},
      blur: function () {},
      keyUp: function () {},
      click: function () {}
    },
    middleware = {
      // custom logic goes here
      focus: function (handler, event) {
        // conditionally use handler(event) to propogate to default or provided handler;
        console.log("wow I did stuff before!")!
        var result = handler(event);
        console.log("and after!");
        return result;
      }
    },
    events = _(events).defaults(handlers);

  _(events).each(function (event, handler) {
    // if we find custom middleware for the handler use it
    // otherwise use identity to return the unchanged handler
    var wrap = (middleware[event] || _.identity);
    $input.on(event, function(event) {
      return wrap(handler, event);
    });
  });

  return this;
};