I have a user collection with tons of properties for each user. One property is an array ('guestlist_submitted') and I am trying to return the most recent 3 items in that array according to the date field.
Using Mongoose, I am able to target that specific property on the user object, but I can't seem to limit or sort them.
I've tried using slice and and a date calculation to return the most recent 3 entires but I am struggling to get it right and not sure whats wrong.
I've tried using Sort/Limit on query builder but I've learned that these dont apply to the array inside the property I am targeting despite me saying " select('guestlist_submitted') as part ofthe query builder.
When I return the result after just targeting the property on the user object, it comes as an array with an object inside and another array inside that object. I am having problems traversing down it to target that inner array to use the slice and date sort.
First try
Users.
find({ fbid: req.query.fbid}).
select('guestlist_submitted -_id').
sort({"guestlist_submitted.date": 'desc'}).
limit(3).
exec((err, result) => {
if (err) throw (err));
if (result) {
res.send(result);
}
Second try:
Users.
find({ fbid: req.query.fbid}).
select('guestlist_submitted -_id').
exec((err, result) => {
if (err) res.send(JSON.stringify(err));
if (result) {
const slicedArr = result.guestlist_submitted.slice(0,1);
const sortedResultArr = slicedArr.sort(function(a,b){return new Date(b.date) - new Date(a.date); });
const newResultArr = sortedResultArr.slice(0, 2);
res.send(newResultArr);
}
The best I can get is 'guestlist_submitted' and the entire array, not sorted and its inside an object inside an array.
I expected the output to be the 3 most recent results from the guestlist_submitted array inside a new array that I can display on the client.
Thank you in advance for your help
EDIT - FIGURED OUT A SOLUTION
I ended up figuring out how to get what I wanted using aggregate()
Users.aggregate([
{
$match: {fbid: req.query.fbid}
},
{
$unwind: "$guestlist_submitted"
},
{
$sort: {'guestlist_submitted.date': -1}
},
{
$limit: 2
},
{
$group: {_id: '$_id', guestlist_submitted: {$push: '$guestlist_submitted'}}
},
{
$project: { guestlist_submitted: 1, _id: 0 }
}
]).exec((err, result) => {
if (err) res.send(JSON.stringify(err));
if (result) {
console.log(result);
res.send(result);
}
});