Google Analytics Event Tracking directive in AngularJS

gistfile1.js

angular.directive('gaTrack', ['$log', 'GoogleAnalyticsService', '$timeout', function ($log, GoogleAnalyticsService, $timeout) {
    return {
        //should always be defined as an attribute
        restrict: 'A',
        //make sure it executes before other directives applied to the same scope
        priority: 10,
        link: function (scope, element, attrs) {
            //initialize variables for use later
            var fieldFocus = 0;
            var fieldSeconds = 0;
            var ms;
            var opts = {};

            //gaAction is required
            if(angular.isUndefined(attrs.gaAction)) {
                $log.error('You must specify an action for Google Analytics event tracking');
                return;
            }

            //gaLabel is optional
            //TODO possibly add noninteraction as a supported attribute
            if(angular.isDefined(attrs.gaLabel)) {
                opts.label = attrs.gaLabel;
            }

            switch(attrs.gaAction) {
                case 'Click':
                    //bind any click actions to the click event (duh)
                    element.bind('click', function (event) {
                        GoogleAnalyticsService._trackEvent(attrs.gaTrack, attrs.gaAction, opts);

                        //If the click action is bound to an outbound link, 
                        //we need to delay the redirect action so that the tracking event has enough time to register
                        //see https://support.google.com/analytics/answer/1136920?hl=en
                        if(element.prop('tagName').toLowerCase() == 'a' && angular.isDefined(element.prop('href')) && angular.isDefined(attrs.gaDelay)) {
                            event.preventDefault();
                            $timeout(function () {
                                document.location.href = element.prop('href');
                            }, 100)
                        }
                    });
                    break;

                //If the action specified is 'Field Completed', 
                //count the number of seconds the user spent in the field
                case 'Field Completed':
                    //radio buttons, checkboxes, and submit buttons are ususally clicked
                    //so we'll bind those fields to click events
                    var excludeTypes = ['radio', 'checkbox', 'submit'];
                    
                    //valid html tag types that we want to track the time spent in the field
                    var tagTypes = ['input', 'textarea', 'select'];
                    var tagName = element.prop('tagName').toLowerCase();
                    var tagType = element.prop('type').toLowerCase();
                    var timerStarted = false;

                    //only count time spent in inputs, textareas, and select boxes
                    if(tagTypes.indexOf(tagName) !== -1) {
                        //if the input type isn't in the excludeTypes array, count the time spent in the field
                        if(excludeTypes.indexOf(tagType) === -1) {
                            //start the timer on focus
                            element.bind('focus', function () {
                                if(timerStarted === false) {
                                    fieldFocus = (new Date()).getTime();
                                    timerStarted = true;
                                }
                            });

                            element.bind('blur', function () {
                                if(timerStarted) {
                                    //stop the timer, and convert milliseconds to seconds
                                    timerStarted = false;
                                    ms = (new Date()).getTime() - fieldFocus;
                                    fieldSeconds = (ms - (ms % 1000)) / 1000;

                                    //send the tracking event
                                    opts.value = fieldSeconds;
                                    GoogleAnalyticsService._trackEvent(attrs.gaTrack, attrs.gaAction, opts);
                                }
                            });

                            //if the element is not a textarea,
                            //we also need to stop the timer if the user hits enter to submit the form
                            if(tagName != 'textarea') {
                                element.keypress(function (e) {
                                    if(e.keyCode == 13) {
                                        if(timerStarted) {
                                            //stop the timer, and convert milliseconds to seconds
                                            timerStarted = false;
                                            ms = (new Date()).getTime() - fieldFocus;
                                            fieldSeconds = (ms - (ms % 1000)) / 1000;

                                            //send the tracking event
                                            opts.value = fieldSeconds;
                                            GoogleAnalyticsService._trackEvent(attrs.gaTrack, attrs.gaAction, opts);
                                        }
                                    }
                                })
                            }
                        }
                        //if the input type IS in the excludeTypes array, trigger the event on click
                        else {
                            element.bind('click', function () {
                                GoogleAnalyticsService._trackEvent(attrs.gaTrack, attrs.gaAction, opts);
                            })
                        }
                        
                    }
                    break;

                default:
                    $log.error(attrs.gaAction + ' is not a valid action');
                    break;
            }
        }
    }
}])