filter in mongodb using node js

Question

Hello everyone I trying to find particular data using a filter but I don't know how we set or use a filter and it properties.I have stored score 1 for true and 0 for false. And I want when next time I call the question it filters the question on scores. So that 0th id question will be displayed on browser and not one

1).This is my schema where I store question id, score and time for every single question

  child:{
      quiz: 

          questionId:{type:String},
          score:{type:Number},
          time:{type:String}
        }
   }

2). This is question schema

     _id:{type:String},
     question:{type:String},
     answer:{type:String}

3). This is my node js code use to fetch and set filter Actually I not getting the idea how we set filter so that next time I call the API only 0th score id question will appear on my browser, not 1

   var childinfo = require('../models/child.js');
   var childquestion = require('../models/question.js');

   this.filter = function(req, res, next){

    async.waterfall({
        function(callback){
            try{
                var query = {child.quiz.score:1};
                var projection = '';
                childinfo.find(query,function(err,data){
                    if(err) return next(err);
                    callback(null, data)
                });
            }
            catch(err){
                console.log(err);
                return next(err);
            }
        },
        function(callback, data){
            try{
                var childq = new childquestion();
                var query = {data.child.quiz.questionId === childq._id};
                var projection = '';
                childquestion.filter(query,projection)
                    .skip()
                    .exec(function(err,data){
                    if (err) return next(err);
                    res.send(data);
                });                        
                }        
            catch(err){
                console.log('Error While Saving the result ' +err);
                return next(err); 
            }
        } 
       });
     } 

Answer 1

Queries on nested field in mongodb can be written like this:

childinfo.find({"child.quiz.score": 1},function(err,data){ .. })

You should quote the fields and use the : instead of ==. So your code should be:

   var childinfo = require('../models/child.js');
   var childquestion = require('../models/question.js');

   this.filter = function(req, res, next){

async.waterfall({
    function(callback){
        try{
            var query = { "child.quiz.score" : 1 };
            var projection = '';
            childinfo.find(query,function(err,data){
                if(err) return next(err);
                callback(null, data)
            });
        }
        catch(err){
            console.log(err);
            return next(err);
        }
    },
    function(callback, data){
        try{
            var childq = new childquestion();
            var query = {"data.child.quiz.questionId":childq._id};
            var projection = '';
            childquestion.find(query,projection)
                .skip()
                .exec(function(err,data){
                if (err) return next(err);
                res.send(data);
            });                        
            }        
        catch(err){
            console.log('Error While Saving the result ' +err);
            return next(err); 
        }
    } 
   });
 } 

edit: code-edit