Search by Date within an Object in Array - node.js

Question

I have the following Mongoose schema:
let ExerciserSchema = new Schema({
username: {
type: String,
required: true
},
exercises: [{
desc: String,
duration: Number,
date: {
type: Date,
default: new Date()
}
}]
});
I want to search by username and limit the exercise results to a date range.
I tried this lookup function:
let user = await Exerciser.find(
{ "username": name },
{ "exercises.date": { "$gte": from }},
{ "exercises.date": { "$lte": to }}
).exec((err, data) => {
if (err) {
res.json({ Error: "Data not found" })
return done(err);
}
else {
res.json(data);
return done(null, data);
}
});
However, it's logging an error and not returning the data.
MongoError: Unsupported projection option: exercises.date: { $gte: new Date(1526342400000) }
I realize from that error it appears like my date is being searched for in milliseconds, but I console.log it right before I run the above function and it's in date mode, which is what I think I want: 2018-05-01T00:00:00.000Z
How can I make this work so that I can search by a date range given my Schema? I can change the format of the date in the Schema if necessary. I'd just like the simplest solution. Thanks for your help.

Answer 1

You're query is wrong. You were trying to write an AND condition, but you separated documents instead of putting everything into one. This means the "second" argument to Model.find() was interpreted as a a "projection of fields", hence the error:
MongoError: Unsupported projection option:
So it's not a "schema problem" but that you sent the wrong arguments to the Model.find() method
Also you need $elemMatch for multiple conditions on elements within an array:
// Use a try..catch block with async/await of Promises
try {
let user = await Exerciser.find({
"username": name,
"exercises": {
"$elemMatch": { "date": { "$gte": from, "$lte": to } }
}
});
// work with user
} catch(e) {
// handle any errors
}
Most importantly you don't await a callback. You either await the Promise like I am showing here or simply pass in the callback instead. Not both.
Exerciser.find({
"username": name,
"exercises": {
"$elemMatch": { "date": { "$gte": from, "$lte": to } }
}
}).exec((err,user) => {
// the rest
})
FYI, what you were attempting to do was this:
Exerciser.find({
"$and": [
{ "username": name },
{ "exercises.date": { "$gte": from }},
{ "exercises.date": { "$lte": to }}
]
)
But that is actually still incorrect since without the $elemMatch the $gte and $lte applies to ALL elements of the array and not just a single one. So the incorrect results would show if ANY array item was less than the date but not necessarily greater than.
For array elements the $elemMatch enforces the "between" of the two conditions.

Answer 2

I managed to get it. This answer matches by username, and filters exercises so they are between the dates with variable names to and from. This is what I had wanted.
let user = Exerciser.aggregate([
{ $match: { "username": id }},
{ $project: { // $project passes along the documents with the requested fields to the next stage in the pipeline
exercises: { $filter: {
input: "$exercises",
as: "exercise",
cond: { $and: [
{ $lte: [ "$$exercise.date", to ] },
{ $gte: [ "$$exercise.date", from ] },
]}
}},
username: 1, // include username in returned data
_id: 0
}}
])
Result:
[
{
"username": "scott",
"exercises": [
{
"desc": "Situps",
"duration": 5,
"_id": "5af4790fd9a9c80c11aac696",
"date": "2018-04-30T00:00:00.000Z"
},
{
"desc": "Situps",
"duration": 10,
"_id": "5afb3f03e12e38020d059e67",
"date": "2018-05-01T00:00:00.000Z"
},
{
"desc": "Pushups",
"duration": 8,
"_id": "5afc08aa9259ed008e7e0895",
"date": "2018-05-02T00:00:00.000Z"
}
]
}
]