There are several high-level web application frameworks for Python that are based around this concept. It's particularly useful for data-oriented apps that let

There are several high-level web application frameworks for Python that are based around this concept. It's particularly useful for data-oriented apps that let the user tweak parameters and update (arbitrarily complex) calculations and visualizations in response. I personally work on one called Shiny (https://shiny.posit.co/py/ https://shiny.posit.co/py/) but there are others including Reflex.dev and Solara.dev. (I haven't looked at Reaktiv beyond the readme but it's clearly based on the same concepts, albeit it's "only" the reactive primitives and doesn't provide the rest of the stack like the frameworks I mentioned do)