angularjs cannot read property then of undefined

Question

I'm trying to return a mongodb collection from my server to the client, but am getting Cannot read property then of undefined on the server-side controller. I get that there is something wrong with the promise but can't seem to solve it. What code changes are needed to fix this? Let me know if more code snippets are needed.

The error occurs on ".then(....)" in the following function.

course.controller.js

function getAll(req,res){
    CourseService.getAll()
        .then(function(result){
            if(result){
                res.send(result);
            }else{
                res.sendStatus(404);
            }
        })
        .catch(function(err){
            res.status(400).send(err);
        });
}

CourseService calls this function:

course.service.js

function getAll(){
    console.log('services/course.service  getALL');
    var deferred = Q.defer();

    db.collection('courses').find().toArray(function(err, result) {
        if (err) deferred.reject(err);
        console.log(result);
        deferred.resolve();
        return deferred.promise;
    });   
}

Answer 1

You need to move the return statement outside:

function getAll(){
    console.log('services/course.service  getALL');
    var deferred = Q.defer();

    db.collection('courses').find().toArray(function(err, result) {
        if (err) deferred.reject(err);
        console.log(result);
        deferred.resolve();
    });   

    return deferred.promise;
}