How can I count the number of all documents in a Collection using Mongoose?

[dessa beca GP]

I am trying to count all Documents in a Collection but I just get 'undefined '. 

I searched in  Mongoose Documentation but the only example that I have is this :

 users.count(query , function(err, result){
      if(err) ...
// count is the result
 var count = result
      });

 So, in Mongoose Documentation I can count the number of documents that match a query passed in the function, but

How can I count all the Documents in a Collection? All without any query? 

In Mongoose terminal I can just do :

db.CollectionName.count()

Does someone know how to do it using Mongoose? 

Thank you.

[James Irwin]

if you want to count a all users in users try

users.count({}, function(err, result){

});

or you can chain it after a find

users.find().count(function(err, count){

});

[Petr Vocelka]

I know it's too late, but at least I can provide helpful answer...

We can take advantage of Mongoose "Driver Access" to solve this problem, so the final result might look like this:

Koa

return users.collection.count();

Express

users.collection.count().exec(function(err, result) {
    if(err) ...
});