Mongoose: can't query array of dates - node.js

Question

I have a test document like that:
{
"_id" : ObjectId("5fb6b0ed9cad6e97cfc24c2d"),
"dates" : [
{
"date" : ISODate("2020-01-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-02-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-03-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-04-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-05-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-06-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-07-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-08-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-09-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-10-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-11-01T00:00:00.000Z")
},
{
"date" : ISODate("2020-12-01T00:00:00.000Z")
}
]
}
Now I want to retrieve only dates $gt: 2020-14-01T00:00:00.000Z. I tried a lot of combinations but none of them worked for me.
This is one of the queries I tried (taken from Mongodb docs):
db.getCollection('things').find({_id: ObjectId("5fb6b0ed9cad6e97cfc24c2d"), "dates.date": { $gt: new Date("2020-04-01T00:00:00.000Z")} } )
But it return all the document, not the gt... i tried using new Date and new ISODate too, but same effect.
Thank you.

Answer 1

First of all, according to mongo documentation dates are in the format "<YYYY-mm-dd>".
Also more formats are allowed, but If you try to use 2020-14-01 as date it will fail (unless you convert string to date with an specific format) because month is 14.
But, answering the question, you need a query like this:
EDITED
db.collection.aggregate({
"$match": {
"_id": ObjectId("5fb6b0ed9cad6e97cfc24c2d"),
}
},
{
"$project": {
"dates": {
"$filter": {
"input": "$dates",
"as": "item",
"cond": {
"$gt": [
"$$item.date",
ISODate("2020-01-14T00:00:00.000Z")
]
}
}
}
}
})
First $match by _id to get only the document you want. And then using $project to create the fields you want to get. You can filter in the array those values whose field date is greater than your date using $filter and $gt
Note that I've used 2020-01-14 to avoid errors.
Example here.
Also another example using $dateFromString in this query.
Edit: You can use $dateFromString and specify a format. Check this example