Pass params as function

Question

i am new on java-Script programming and i develope NodeJs. I wanna call one Function, which requires functions as parameter:

Will be called:

module.exports = {
        //pool is has been defined
        connection: function() {
            pool.getConnection(function(err, conn) {

                return conn;
            });
        }

};

At next other node.js file, which call that:

var connectionPool = require('./connPool.js');
var connection = connectionPool.connection;
var tempConnection  = connection.getConnection(???);

I need return-value from method "getConnection" (above this code) How can i get it??

Thx.