Nodejs export not returning value

Question

I have a nodejs export like this

exports.add = function(req){

    var newUser = new User({
        email: req.body.email,
        password: req.body.password,
    });

    // Attempt to save the user
    newUser.save(function(err) {
        if (err) {
            return true;

        }
        return false;
    });

}

But it's giving as undefined when i call the function like this

var value = instance.add(req);

Here instance is the imported instance of the javascript file

Answer 1

As stated in comments by @Ben Fortune you couldn't simply return a value from an asynchronous function call. you should use callbacks or promises:

The callback way:

exports.add = function (req, callback) {

    var newUser = new User({
        email: req.body.email,
        password: req.body.password,
    });

    // Attempt to save the user
    newUser.save(function(err) {
        if (err) {
            callback(err, null);
        }
        callback(null, newUser.toJSON()) ;
    });

}

Then:

instance.add(req, function(err, value) {
  if (err) throw err;
  // use value here
});

Read More: How do I return the response from an asynchronous call? And implement promise way if you prefer.