I'm in the middle of building a fairly large application which features a fairly deep and complex user interface for one part of it. I seriously don't know how

I'm in the middle of building a fairly large application which features a fairly deep and complex user interface for one part of it. I seriously don't know how I would have done it without react (or something similar). There are so many parts to it and the thought of having to do this by manually changing the DOM and trying to keep everything in 'sync' makes me feel ill. Lots of the components call our Rest API and the changes are reflected in the redux store, which then trickles the data down through the entire application. Everything stays nicely reactive and in sync, without me having to worry too much about it. Another thing I love is the ability to make large changes in the application without too much breaking. Just remove/replace a component and the rest of the app keeps working as normal. It really is lovely. A few years ago I was involved in building another fairly application, with nothing but pure javascript, our own little MVC framework and manual DOM manipulations. I dreaded everyday I was working on it. As most of you will know, clients change their mind, requirements change, things need shifted around when development is in the early stages and everything is in a state of flux. I can remember trying to make changes and realising that other things would randomly stop working if they depended on certain DOM elements. Hated it. Maybe there was an element of bad design and pre-development planning, but it was awful. Now, front end development is something that I really look forward to.