Issue in returning plain json object from mongo

Question

I have a function that finds one object inside my schema database. If I console.log it, it displays correctly. But outside the function when I use it or console log it, It returns a null object. Please help

My function:

var pushQues = function(quesObj){ 
var query = {AnswerId: 'Texas'};
Question.findOne(query).lean().exec(function(err,docs){
    console.log(docs.Ques);
    console.log(docs);
    quesObj = docs;
});};

Console(Returns Correctly):

Which is the biggest state?
{ _id: 5815366d49fd95ec160728d8,
 Ques: 'Which is the best language?',
 Answers: [ 'Texas', 'Georgia', 'New york', 'Ohio' ],
 AnswerId: 'Texas' }

Trying to retrieve quesObj from outside function:

var quesObj={};
pushQues(quesObj);
console.log('and quesobj here: '+ quesObj);
console.log('question here: '+ quesObj.Ques);

console(Doesnt work):

 and quesob here: [object Object]
 quesob here: undefined

Can you print your first console with stringify and check the value is coming or not console.log(JSON.stringify(quesObj))? — abdulbari
– abdulbari, Commented Oct 30, 2016 at 12:20
as you are overriding it and then assign it which is obviously getting undefined — Wasiq Muhammad
– Wasiq Muhammad, Commented Oct 30, 2016 at 12:29

abdulbari · Accepted Answer · 2016-10-30 13:22:11Z

1

It should be the issue of async nature try to pass the callback to get it.

var pushQues = function(quesObj, callback) {
  var query = {
    AnswerId: 'Texas'
  };
  Question.findOne(query).lean().exec(function(err, docs) {
    console.log(docs.Ques);
    console.log(docs);
    callback(null, docs);
  });
};


pushQues(quesObj,function(err,result){
console.log('and quesobj here: '+ result);
console.log('question here: '+ result.Ques);  
});

Update

var async = require('async');
async.waterfall([
  function(callback) {
    var pushQues = function(quesObj, callback) {
      var query = {
        AnswerId: 'Texas'
      };
      Question.findOne(query).lean().exec(function(err, docs) {
        console.log(docs.Ques);
        console.log(docs);
        callback(err, docs);
      });
    };
  }
], function(err, result) {
if(!err){
  console.log(result);
}
});

edited Oct 30, 2016 at 13:22

answered Oct 30, 2016 at 12:45

abdulbari

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6 Comments

Bk Razor Over a year ago

This work, but only from within the call back, Is there anyway to set an object outside to result?

abdulbari Over a year ago

Yes, you can use promise or async module to get it

Bk Razor Over a year ago

Okay I will research that a little more and let you know what happens

abdulbari Over a year ago

use waterfall method of async module. see my updated answer

Bk Razor Over a year ago

Thank you sooo much You all made me realize that I need to learn async a little better. Can't tell you how many hours I put into this problem :)

|

lucas.coelho · Accepted Answer · 2016-10-30 12:45:46Z

1

The problem is that you are replacing the object reference. You can like this:

var quesObj={ result: null };
pushQues(quesObj);
console.log('and quesobj here: '+ quesObj);
console.log('question here: '+ quesObj.result.Ques);

The function:

var pushQues = function(quesObj){ 
  var query = {AnswerId: 'Texas'};
  Question.findOne(query).lean().exec(function(err,docs){
      console.log(docs.Ques);
      console.log(docs);
      quesObj.result = docs;
  });
};

Another option is to use callback:

var pushQues = function(callback){ 
  var query = {AnswerId: 'Texas'};
  Question.findOne(query).lean().exec(function(err,docs){
      console.log(docs.Ques);
      console.log(docs);
      callback(err, docs);
  });
};



var quesObj={ result: null };
pushQues(function(err, obj) {
  if (err) console.log(err);
  console.log('and quesobj here: '+ quesObj);
  console.log('question here: '+ quesObj.Ques);
});

answered Oct 30, 2016 at 12:45

lucas.coelho

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3 Comments

Bk Razor Over a year ago

So for the first answer my console was still null and undefined

Bk Razor Over a year ago

The second answer with the call back: console was [object Object] and undefined

lucas.coelho Over a year ago

Try to log the object like this: console.log('and quesobj here: ', quesObj); with a comma instead of plus sign

Wasiq Muhammad · Accepted Answer · 2016-10-30 13:08:56Z

1

I am assuming you want this pushQues function declaration as it is an issue of async

var pushQues = function(quesObj, callback){ 
var query = {AnswerId: 'Texas'};
var quesObj = {} ;
return Question.findOne(query).lean().exec(function(err,docs){
    console.log(docs);
    quesObj = docs;
    callback(null, docs);
});};

calling pushQues Function

pushQues(quesObj,function(err,result){
console.log('and quesobj here: '+ result);
console.log('question here: '+ result.Ques);

edited Oct 30, 2016 at 13:08

answered Oct 30, 2016 at 12:35

Wasiq Muhammad

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7 Comments

Bk Razor Over a year ago

That's still sending back a null and undefined

Wasiq Muhammad Over a year ago

what is an output og console that is used in pushQues funtion

Bk Razor Over a year ago

It returns [object Object]

Wasiq Muhammad Over a year ago

make return in Question.findOne then when you calling pushQues after console RESULT what is ?

Bk Razor Over a year ago

Inside the function if returns the correct function, but outside returns RESULT Promise{<pending>} . question here: undefined

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