Extending underscore to extend objects' functions with this._super

gistfile1.js

// Description:
// Adds this._super method to objects that are extended and have the
// same function, keeps original function as reference on this._super

var _ = require('underscore');

_.extendWithSuper = function(obj) {
  if (!_.isObject(obj)) return obj;
  var source, prop;
  for (var i = 1, length = arguments.length; i < length; i++) {
    source = arguments[i];
    for (prop in source) {

      if (hasOwnProperty.call(source, prop)) {
        // check to see if both methods are functions
        if(_.isFunction(source[prop]) && _.isFunction(obj[prop])){

          var Class = function(){
            this._super = obj[prop];
          };

          var tmpClass = new Class();

          obj[prop] = function(){
            return source[prop].apply(tmpClass, _.toArray(arguments));
          };

          obj[prop].prototype = source[prop].prototype;

        } else {
          obj[prop] = source[prop];
        }
      }
    }
  }
  return obj;
};

var events = {
  click: function(){
    console.log('clicked original');
  }
};

var events2 = {
  click: function(){
    this._super();
    console.log('clicked inherited');
  }
};

var events3 = _.extendWithSuper(events, events2);

events3.click();
// clicked original
// clicked inherited
// undefined