从模块函数node.js返回响应

Question

I have an app file with routes in it and another module written which has the mongoose schema and the model object of a collection. Code for app is:

app.post("/saveNode", function(req, res) {
    console.log(req.body.clientId)
    if(req.body.hasOwnProperty("clientId")) {
        defferedObject = nodeDbObject.returnCollectionObject(req.body);
    }
}

From the route I am calling a function of mongoose model(returnCollectionObject) object which will save the body obtained in post call to the database.This function is written in the module. Code for the same is given below:

exports.returnCollectionObject = function(body) {
    var collection = "refresh_hierarchy";
    var nodeModelObject = mongoose.model(collection, folderSchema);
    return nodeModelObject.create(body, function(err, resp) {
        if(err == null) {
            return resp;
        }
    });
};

I am calling this function from my route written for post. And i want the object returned from this function(resp) from inside my route so that i can use some of its fields to be returned in the response . Tried using .done() on the defferedObject but return resp does not return anything. Am i doing it right? Here is the code with done function.

app.post("/saveNode", function(req, res) {
    if(req.body.hasOwnProperty("clientId")) {
        defferedObject = nodeDbObject.returnCollectionObject(req.body);
        defferedObject.done(function(resp) {
            res.send({"data": resp.uniqueNodeId, "error": err});
            res.end();
        });
    }
}

This is just my first crack at writing a node service.Can Anyone help me out with this.Can it be done like that or not? The error i am getting is as below.

TypeError: Cannot call method 'done' of undefined

Answer 1

With async calls, returning value won't work, you need to use callbacks:

exports.returnCollectionObject = function(body, callback) {
    var collection = "refresh_hierarchy";
    var nodeModelObject = mongoose.model(collection, folderSchema);
    nodeModelObject.create(body, function(err, resp) {
         callback(err, resp);  // err might be null or some error, check in caller
    });
};

In your route, do this:

var dbObj = require('./nodeDbObject');  // assume you name file
                                        // nodeDbObject.js which
                                        // contains 
                                        // returnCollectionObject()
app.post("/saveNode", function(req, res) {
    if(req.body.hasOwnProperty("clientId")) {

        dbObj.returnCollectionObject(req.body, function(err, result) {
            if (err) {
                res.send({error: err});
            } else {
                res.send({data: result});
            }
        });
    } else {
        res.send({error: "no clientId"});
    }
}