For a tool I am working on it would be useful to have a callback that gives me the current mouse position in lat lng when the mouse is moved.

it appears that onMouseMove is an internal method but it is not possible to register a user callback on the event.
https://github.com/google-map-react/google-map-react/blob/master/src/google_map.js#L1158

If it is possible to have a user callback for mouse move please forgive me for not finding it and we can close this issue.