mr-file.js

function sendTrackEvent (eventData) {
    window.ga('send', Object.assign({hitType: 'event'}, eventData);
}

function trackVideoEvents (videoElement) {
    var $videoElement = $(videoElement);
    var markers = [.1, .2, .3, .4, .5, .6, .7, .8, .9, 1];
    var gaLoggingName = this.dataset.gaLoggingName;
    var isTrackingProgress = false
    
    function checkVideoProgress () {
        var currentMarker = markers[0];
        
        if (isTrackingProgress && videoElement.duration && currentMarker) {
            var progress = videoElement.currentTime / videoElement.duration;
            
            if (progress >= currentMarker) {
                markers.shift(); // Remove first
                
                // calc mark to percentage
                var fixedMarker = parseFloat((currentMarker * 100).toFixed());
                fixedMarker = fixedMarker + '%';
                
                if (isTrackingProgress > 1) {
                    fixedMarker = 'complete';
                }
                
                sendTrackEvent({
                    hitType: 'event',
                    eventCategory: 'Video',
                    eventAction: fixedMarker,
                    eventLabel: gaEventLabel
                });
                
                // console.log(fixedMarker);
            }
            
            isTrackingProgress = progress < 1; // Are we finished?
            
            window.requestAnimationFrame(checkVideoProgress);
        }
    }
    
    function initProgressTracking () {
        isTracking = true
        
        checkVideoProgress()
    }
    
    $videoElement.on('play', function () {
        sendTrackEvent({
            eventCategory: 'Video',
            eventAction: 'Start',
            eventLabel: gaLoggingName
        })
    })
    
    if (typeof videoElement.duration === 'number' && videoElement.duration > 0) {
        initProgressTracking()
    } else {
        $videoElement.once('durationchange', initProgressTracking)
    }
}

fl.videoLog = {
    init: function () {
        $('video[data-ga-logging-name]').each(trackVideoEvents)
    }
}