What is best way to use nodejs with sqlite3 connections

I am playing with nodejs and sqlite3 The server will be used for making rest calls using express.

Being kind of new to node, i have two questions on how to manage the db connection.

1 ) Do i open/connect to the

var db = new sqlite3.Database(file);

before the listener and then close the connection on exit of the server or in each route i open the connection and close when the rest call is complete.

2 ) how do i pass the connection to a separate route file? I tried based on some examples, but get the error message "Sever initialization failed Cannot call method 'indexOf' of undefined" (see code below the exception)

Trace
at Object.<anonymous> (c:\Work2\server.js:154:13)    at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Module.runMain [as _onTimeout] (module.js:497:10)
at Timer.listOnTimeout [as ontimeout] (timers.js:112:15)

these are

//server.js
var db = new sqlite3.Database(file);
var apiRoutes = require('./routes/apiRoutes')(db);

//apiRoutes.js
module.exports = (function (db) {

    router.get('/userlist', function (req, res, next) {
        res.json('{stuff...}');
    });
    return router;

})();

Thanks for any help