Add scrollheight and width, for more precise scroll detection.
Add unmodified riveted.js
Include riveted as a library.
Start to move towards snowplow integration.
Remove obsolete code, such as Google Analytics.
Use helpes.AddEventListener, and remove the addListener method.
Integrate engagement tracking with snowplow tracker.
rename riveted library to engagement.
Pass in activity handler to engagement timer so pings are sent when timer is incrementing.