findById returning a list of documents instead of a single result
The code is correct, the way you are making request is wrong
Your Format :
http://localhost:3000/events?id=someidid = someID in the URL represents a GET query parameter.
If you are using wildcard parameters like :id in the route, then the request URL should be :
http://localhost:3000/events/someidsomeid will now be present in req.params.id
You are getting all the objects is because the variable id is undefined in your case, undefined parameters are omitted by default. So it is same as calling : EventModel.findById({}, callback)
Thanks