I rewrote my google map component according to what was suggested here, see https://gist.github.com/jhchabran/e09883c3bc1b703a224d#file-2_google_map-cljs

it makes use of props to update the marker position and an atom to hold the gmap instance.

I’ve used a reagent/atom but I think a plain atom would do the job since it’s just about storing a reference to that gmap instance, which is needed both in :componenent-did-mount and :component-did-update