Before two weeks ago or so, it used to be Backbone views and models, and everything was on our main store app, and our mobile web app, but actually, we just switched our mobile web app to using ReactJS for the interface. So it’s using Backbone models but ReactJS front-end components. Really, it was borne out of the frustration with how the Backbone model-view bindings worked, and it wasn’t especially performant for large views, and we had to do lots of tricks to make it performant. But swapping that out with React views meant that it could be both simpler and faster without having to spend a lot of time on that.
One other interesting thing about that is, since React actually works okay with the Backbone models and the Backbone router and stuff like that, we didn’t have to rewrite the mobile web application and update it to ReactJS. Rewrites are almost always a bad idea. We were able to upgrade pieces of it at a time, move on to React, and now the entire thing is using React and just has the Backbone router and models and stuff like that that we already had, so it's a lot faster. React