How to return values from mongoose findOne method to the calling function

Question

I have a situation where i am badly stuck. Tried a lot but no worth.
I have a nodejs application, where i am reading data from mongodb.
I have a main method, from where I am calling a fetchMongo() method and all other functions. I need the fetchMongo function to return the result to the Main. The main method has an object obj that will get passed to all the functions.
The code below I tried: Its not working.
console.log inside fetchMongo() works fine, but fetchMongo() is not returning the value to Main.
Please help.

function fetchMongo(obj)
{
    var defer = Q.defer();
    serviceHealthConfig.findOne({}, '', { sort: {'_id' : -1} }, function(err, nodes){
        var struct={}
        if(err) 
            console.log(err);
        //console.log(nodes);
        obj = nodes;
        return obj;
    });
    defer.resolve(obj);
    return defer.promise;
}

function main(){
    var obj = { };
    var nodesObject = fetchMongo(obj)
                    .then(methOne(obj))
                    .then(methTwo(obj))
                    .then(methThree(obj))
}

Answer 1

Your defer.resolve should be called inside the find one callback. Like below:

    function fetchMongo(obj)
{
    var defer = Q.defer();
    serviceHealthConfig.findOne({}, '', { sort: {'_id' : -1} }, function(err, nodes){
        var struct={}
        if(err) 
            console.log(err);
        //console.log(nodes);
        obj = nodes;
        defer.resolve(obj);
    });
    return defer.promise;
}

Moreover findOne needs a parameter as well; what to find.

Hope this helps!