Search in Embedded Documents in MongoDB? - arrays

Question

I have document as shown
[
{
"Users": [
{
"Name": "Kartikey Vaish",
"_id": "1",
},
{
"Name": "Witcher Proxima",
"_id": "2",
}
],
"_id": "12",
},
{
"Users": [
{
"Name": "Witcher Proxima",
"_id": "2",
},
{
"Name": "Saga",
"_id": "4",
}
],
"_id": "13",
}
]
I want to search for those documents whose Users array has that particular ID
For Example if
ID == 1 // should return
[
{
"Users": [
{
"Name": "Kartikey Vaish",
"_id": "1",
},
{
"Name": "Witcher Proxima",
"_id": "2",
}
],
"_id": "12",
}
]
ID == 2 // should return
[
{
"Users": [
{
"Name": "Kartikey Vaish",
"_id": "1",
},
{
"Name": "Witcher Proxima",
"_id": "2",
}
],
"_id": "12",
},
{
"Users": [
{
"Name": "Witcher Proxima",
"_id": "2",
},
{
"Name": "Saga",
"_id": "4",
}
],
"_id": "13",
}
]
ID == 4 // should return
[
{
"Users": [
{
"Name": "Kartikey Vaish",
"_id": "1",
},
{
"Name": "Saga",
"_id": "4",
}
],
"_id": "13",
}
]
As you can see from above my query should return only those objects whose "Users" array contains an object with given ID. I tried this but it doesn't work.
const chats = await Chats.find({
Users: { $elemMatch: { _id: "1" } },
});
// this returns an empty array
const chats = await Chats.find({
Users: { $elemMatch: { Name: "Kartikey Vaish" } },
});
// this returns
[
{
"Users": [
{
"Name": "Kartikey Vaish",
"_id": "1",
},
{
"Name": "Witcher Proxima",
"_id": "2",
}
],
"_id": "12",
}
]
What am I doing wrong here?
Is it something related to _id paramter?
EDIT:
My Chats Schema looks like this -
const Chats = mongoose.model(
"Chats",
new mongoose.Schema({
Users: {
type: Array,
required: true,
default: [],
},
})
);

Answer 1

Update your schema as shown below
const Chats = mongoose.model(
"Chats",
new mongoose.Schema({
Users: [{
_id: {
type: String,
required: true, // Include only if needed!
unique: true // Include only if needed!
},
Name: {
type: String,
index: true // Include only if needed!
}
}]
})
);
If you do not explicitly mention _id MongoDB will create _id field as ObjectId.