> So far the only thing I can imagine that comes close might be something like a chat application. Sorry, but if you think that chat is a complex UI you obviou

> So far the only thing I can imagine that comes close might be something like a chat application. Sorry, but if you think that chat is a complex UI you obviously don't understand what type of complexity I'm talking about. Multi-page, multi-level forms with a lot of conditional rendering are far bigger problem to handle than chat. Challenge is not in a single particularly advanced action, forms I'm talking about are mostly just a bunch of ifs and event handlers that update the DOM accordingly. Problem is the overall complexity arising from a sheer number of different combinations you need to control, so you end up with thousands and thousand of lines of jQuery functions and events interacting and stepping on each other's toes. For instance I'm currently working on an IP management app for big, international law firm. In order to invoice a client for even a very basic service like trademark registration you need to handle multiple countries, multiple laws, multiple currencies, and it has to be all in one dynamic form because they need to fill hundreds of those and it has to be simple and quick. These forms are huge, each loads a dozen of subforms, dialogs, etc. conditionally based on different business and legal rules that apply and user has to be able to edit all of that interactively. I've built the first version of that app 10 years ago using jQuery and it worked for a long time, but it took us more than 3 years to fully finish and it was huge and hard to maintain and had a number of limitations, as some legal rules were just too complex to handle. We now did a new version in Vue in less than 6 months. Much easier, much cleaner, our code deals just with our logic, not touching DOM at all, so it's much easier to debug and maintain it. Overall much nicer experience and thanks to that we were able to solve a number of problems that the old version had. And this experience translates to pretty much any serious business web app that I've ever built.