NodeJS - how to return arrays from a module

Question

NodeJS - how to return arrays from a module

I've got a module called 'userinfo.js' retrieving info about users from DB. Here's the code:

exports.getUserInfo = function(id){
db.collection("users", function (err, collection) {
    var obj_id = BSON.ObjectID.createFromHexString(String(id));
    collection.findOne({ _id: obj_id }, function (err, doc) {
        if (doc) {
            var profile = new Array();
            profile['username']=doc.username;
            return profile;
        } else {
            return false;
        }
    });
});
}

From index.js (controller for index page, from which I'm trying to access userinfo) in a such way:

var userinfo = require('../userinfo.js');

var profile = userinfo.getUserInfo(req.currentUser._id);
console.log(profile['username']);

Node returns me such an error:

console.log(profile['username']);   -->     TypeError: Cannot read property 'username' of undefined

What I'm doing wrong? Thanks in advance!

arrays
node.js
module
export
return

Answer 1

You're returning profile['username'] not the profile array itself.

Also you could return false, so you should check profile before accessing it.

EDIT. Looking over it again, your return statement is inside a callback closure. So your function is returning undefined. One possible solution, (keeping with node's async nature):

exports.getUserInfo = function(id,cb){
db.collection("users", function (err, collection) {
    var obj_id = BSON.ObjectID.createFromHexString(String(id));
    collection.findOne({ _id: obj_id }, function (err, doc) {
        if (doc) {
            var profile = new Array();
            profile['username']=doc.username;
            cb(err,profile);
        } else {
            cb(err,null);
        }
    });

}); }

    var userinfo = require('../userinfo.js');

    userinfo.getUserInfo(req.currentUser._id, function(err,profile){

      if(profile){
       console.log(profile['username']);
      }else{
       console.log(err);
      }
});