Toggle chart series in clojurescript
If your dataset were coming from an outside source, like an API call, I'd say the atom would make sense.  In this case, your dataset is static.  In that case, I think I might find it more intuitive to use a var for the series and then select the items out that you want to plot.   In that case, your state is really just a list of which series (you are selecting). 

So, if you had all your series:

(def all-series
  {:series1 :...series1
   :series2 :...series2
   :series3 :...series3})


!chart might contain #{:series1 :series3} and you could get all the values out using (select-keys all-series @!chart).  

You might find you can avoid the atom altogether, but at the very least I'd always look for ways to keep that state as simple as