I haven't properly thought this through but is here a sense in which the React "one way data flow" paradigm is a case of rediscovering immediate mode GUIs on the web?
IMHO there's a lot of overlap between the reactive UI philosophy and the immediate mode UI philosophy. The main difference is IMHO that React is "mainly data" while IMGUI is "mainly code". But code is data and data is code, so... :)