mongoose FindbyId and where array match to a string - node.js

Question

I want to query a user by id, and then bring only the the foods that match to a type, how can i do this?
var type = 'fish';
var id = '597a348286ffe50d882a3033';
User.findById(id, { 'food.type': type }, 'food', function(err, model) {
if (err) {
console.log(err);
}
if (!model) {
console.log('no model');
}
if (model) {
console.log(model);
}
});

Answer 1

I would use aggregate combined with $filter:
User.aggregate([{
$match: { '_id': ObjectId('597a348286ffe50d882a3033') }
}, {
$project:
{
food: {
$filter: {
input: '$food',
as: 'food',
cond: {
$eq: ['$$food.type', type]
}
}
}
}
}])
This will first select the document matching the given Id then will return the list of foods of the given type.

Answer 2

Just filter the food after you get the user.
User.findById(id, function (err, user) {
if (err) {
console.log(err);
}
if (!user) {
console.log('no user');
}
if (user) {
var food = user.food.filter(function (food) { return food.type === type; });
}
});

Answer 3

You can create an obj something like this
var obj =
{
_id:'597a348286ffe50d882a3033',
'food.type' : 'fish'
}
and then pass this function as filter
User.find(obj, function(err, model) {
if (err) {
console.log(err);
}
// find will return empty array and not null
if (!model.length) {
console.log('no model');
}
if (model) {
console.log(model);
}
});

Answer 4

If you are finding the object using mongo _id field you don't have to use additional filter function after query execution you directly specify in the search query
Model.findOne({_id: '123jasdoisd123', 'food.type': type },
function(err, food){
if(err) return err;
if(!food){
// send the empty data
return []
}
return food;
}
)