rtree in front end working

So we send as many object requests as we need objects (because 'object' is emitted once every forEach turn).
I wonder if we're not wasting bandwidth doing so. I feel like the overhead of Socket.io compared to the object id is expensive.
Maybe we should gather all the ids we want (with `results.filter`) and then send a single message with this array as data.
Either do it now or create an issue so we keep it in mind.