Which js library provides this kind of scrolling/animation functionality?

I am trying to find the best library for animations on single-page applications. I very much like the way todoist has implemented this:

http://ift.tt/1L5gOw8

Does anyone know which library they use, or which library provides this kind of functionality? Key feature I need: - animation not dependent on scrolling, but only triggered by it. I found a lot of very great libraries, but they provided only animations that depended on how far the user actually scrolled. For instance ScrollMagic.