Interesting, in my experience React allows me to write more testable code in the front-end than I ever could. Given how React will handle updates to the DOM giv

Interesting, in my experience React allows me to write more testable code in the front-end than I ever could. Given how React will handle updates to the DOM given changed state, I can extract complex state manipulation code (i.e. code that's most important to test) into independent functions that take state and an event and produce new state, rather than having that all intertwined with DOM manipulation code. And when it comes to testing what your DOM looks like, even though that does often involve spying for changes (after all, you're testing whether they occur), that's not on the actual DOM but on the virtual DOM, which makes it easy and efficient to run in a non-browser environment.