is there a way for producer to know is the channel open or closed for writing?

You can offer! for put only if open

Does anyone know how to make go blocks "reload" in CLJS+Fighweel app?

Ah... just kind of a solution above 🙂

in cljs I tend to make my go-loops as simple as possible and move all non-async code into separate functions, this way the problem is solved for me, because it is unlikely for me to be rewriting code in go-loops, usually it is the functions called from them

and it is a good practice overall to keep your go blocks as lean as possible, for debugging and to avoid core.async state machine complexity