Search data in mongodb according to field values - arrays

Question

I am using mongodb and node.js. In my database i have 6 fields that is
bid
color (Array)
size (Array)
cat_id
sub_cat_id
All is working fine. Now i want to add filter in my code. In filter area i have add this all fields. user select multiple colors and sizes so it will come in Array format but most of the time user will not select color option or size option at that time field values comes blank so my filter will not take any result from database. so i want to remove color or size field if value is empty during search. I have tried below code but its not working.how i do this.
var catId = new Array();
var sort = saveFilterSort.sort;
var filter = req.body;
if(req.body.catId){
catId.push("category_id:"+req.body.catId);
}
if(req.body.subcatid){
catId.push("sub_category_id:"+req.body.subcatid);
}
if(req.body.minprice){
catId.push("price:{$gt:"+req.body.minprice+"}");
}
if(req.body.maxprice){
catId.push("price:{$lt:"+req.body.maxprice+"}");
}
if(req.body.color){
catId.push("color:{$in:"+req.body.color+"}");
}
if(req.body.size){
catId.push("attribute:{$in:"+req.body.size+"}");
}
var finalCat = catId.join(',');
console.log(finalCat);
console.log(catId);
if((filter) && (sort)){
Product.find(
{
brand_id:bid, finalCat
},
function(error,fetchallFeatProds)
{
console.log('#######################');
console.log(fetchallFeatProds);
console.log('#######################');
callback(error,fetchallFeatProds);
}).sort( {_id:-1,price:-1} );
This code is not working. Please help me.

Answer 1

Mongoose find prototype handle json and not string
var query = {brand_id:bid};
var sort = saveFilterSort.sort;
var filter = req.body;
if(req.body.catId){
query.category_id = req.body.catId;
}
if(req.body.subcatid){
query.sub_category_id = req.body.subcatid;
}
if(req.body.minprice){
query.price = {$gt:req.body.minprice};
}
if(req.body.maxprice){
query.price = {$lt:req.body.maxprice};
}
if(req.body.color){
query.color = {$in:req.body.color};
}
if(req.body.size){
query.attribute = {$in:req.body.size};
}
if((filter) && (sort)){
Product.find(query, ...