Little Google Analytics tracking helper I use in some of my projects, requires jQuery.extend() method

gistfile1.js

//--------------------------------------------------------------
        //  Google analytics tracking helper
        //  @Author         :   Chris Panayotov / info[at]bassta[dot]bg
        //--------------------------------------------------------------
        //  Usage: tracker.track({eventCategory: '', eventLabel:''});
        //  @eventCategory  :   Typically the object that was interacted with (e.g. button)
        //  @eventAction    :   The type of interaction (e.g. click)
        //  @eventLabel     :   Useful for categorizing events (e.g. nav buttons)
        //  More info @ https://developers.google.com/analytics/devguides/collection/analyticsjs/events
        //--------------------------------------------------------------

        var tracker = (function ($, window) {

            var hasGA = window.ga;
            var defaults = {
                eventCategory: 'button',
                eventAction: 'click',
                eventLabel: ''
            };

            function track(_trackObj) {
                var trackObj = $.extend(defaults, _trackObj);
                if (hasGA) {
                    window.ga('send', {
                        'hitType': 'event',
                        'eventCategory': trackObj.eventCategory,
                        'eventAction': trackObj.eventCategory,
                        'eventLabel': trackObj.eventLabel
                    });
                } else {
                    console.log('[Google Analytics tracker not found, failed to track]', trackObj);
                }

            }

            return {track: track};

        })(jQuery, window);