call db.loadServerScripts on connection startup - node.js

Question

I have some server-side helper functions in system.js collection, which are then used in node.js. However sometimes, they are undefined.
Here is the scenario:
I load these functions once, on server start:
db.eval('db.loadServerScripts()', function(err, result) { ... });
So this is called only once on start, not for every request.
From now on I can call e.g.:
db.eval('getNextSequence(\'test\')', function(err, seq){});
But sometimes I get the error, that getNextSequence is undefined. I suspect those functions to exist only in current connection scope. So maybe when node receives new connection, the functions are not set.
Is there any way to use those functions in node.js, but to have them reliably available always?
Example scenario:
//1./ this function is stored in system.js
getNextSequence: function(name)
{
var ret = db.counters.findAndModify({
query: { _id: name },
update: { $inc: { seq: 1 } },
new: true,
upsert: true
});
return ret ? ret.seq : null;
}
//2./ this is called on nodejs server startup (once for server lifetime)
var mongo = require('mongoskin');
var db = mongo.db("mongodb://localhost:27017/mydb", {native_parser:true});
//...
db.eval('db.loadServerScripts()', function(err, result) {
//...crash if failed
});
//3./ this is used in node.js code, on request processing:
db.eval('getNextSequence(\'someNamespace\')', function(err, seq){
// int seq is converted to string slug
// a new entity with slugId is saved to collection
});