I think the "callbacks lead to spaghetti code" view is just an inadequate expression of the problem. I believe that people who are averse to callbacks feel so b

I think the "callbacks lead to spaghetti code" view is just an inadequate expression of the problem. I believe that people who are averse to callbacks feel so because callback-ridden code doesn't compose well. Compose-ability is an important practical consideration, but many async libraries solve this problem to a fair extent. Also, reactive programming is not exactly the solution to callbacks like structured programming is to goto. "B needs to update automatically when A changes" criterion is extraneous to the problem.