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MongoDB - set nested field using name from variable

I want to create new field in my document, lets call it "shelf", it will be an object.
Next I want to make two $set operations - I want to put arrays named "Tom" and "Anna" into my "shelf".
The problem is that I can't match correct query to do that.
I'm using nodejs MongoDB driver.
var myid = 'Tom-Anna'
var TomArray = ["Tom"]
var AnnaArray = ["Anna"]
await db.collection('people').updateOne(
{ pairid: myid },
{ $set: { shelf: TomArray } },
{ upsert: true }
)
await db.collection('people').updateOne(
{ pairid: myid },
{ $set: { shelf: AnnaArray } },
{ upsert: true }
)
Finally, the "shelf" document containing only "AnnaArray", because it's overwriting previously added "TomArray".
I can't add "Tom" and "Anna" array to "shelf" at the same time because content of arrays are generated separately.
I was trying this code:
var name = 'Tom'
var array = ['Tom']
await db.collection('people').updateOne(
{ pairid: myid },
{ $set: { shelf[name]: array } },
{ upsert: true }
)
But it's throwing following error:
{ $set: { shelf[name]: array } },
^
SyntaxError: Unexpected token [
My goal is to set my field like JSON:
"shelf": { "Tom": ["Tom"], "Anna": ["Anna"] }

You can use dot notation to specify nested key name:
var name = 'Tom'
var array = ['Tom']
db.people.update({ pairid: 1 }, { $set: { [`shelf.${name}`]: array } })

Node.js: Cannot read property 'then' of undefined (nested query)

I'm trying to update a field in a MongoDB collection which has nested documents. I have to increase a certain value. The update query works just fine, but I need to nest it in another query where I get the current value, so I could increase it.
The nesting worked just fine when I used a faulty find() method. I realized I must use aggregate(). I can't get it working, the method returns undefined for some reason. I've tried the same aggregate query in the shell and it works, so it has to do something with the Node.js
The function that fails:
static addPointsToUser(mainId, userId, pointsToAdd) {
const db = getDb();
function getCurrent() {
db.collection('mycoll')
.aggregate([
{ $match: { _id: mainId } },
{ $unwind: '$userPoints' },
{ $match: { 'userPoints._id:': userId } },
{ $group: { _id: 'userPoints._id', userPoints: { $push: '$userPoints.points' } } }
])
}
function updateNew(newPoints) {
db.collection('mycoll')
.updateOne(
{ _id: mainId },
{ $set: { "userPoints.$[elem].points": newPoints } },
{
multi: true,
arrayFilters: [{ "elem._id": userId }]
}
)
}
return getCurrent()
.then(result => {
console.log(result);
const newPoints = result.userPoints[0];
return updateNew(newPoints)
.then(result => {
console.log(result);
return result;
})
})
}
The document looks like this:
{
"_id": ObjectId("5d4048f56a895612acabe0a9"),
// Some other fields
"userPoints": [
{ "_id": "manualID1", "points": 80 },
{ "_id": "manualID2", "points": 90 }
]
}
Expected aggregate result:
{ "_id" : "manualID1", "userPoints" : [ 90 ] }
Mongo shell gives the result seen above.
Actual result:
TypeError: Cannot read property 'then' of undefined
If I log the aggregate result it prints and empty array ( [] ).

Your methods getCurrent and updateNew are not returning anything. Which mean you are using .then() on something which is undefined as stated by your error message.
Adding a return statement before db.collection('mycoll') should help you with that.

how do I increment field in array of objects after finding it (using findOne()) and before saving it?

I want to update an object inside an array of schemas without having to do two requests to the database. I currently am incrementing the field using findOneAndUpdate() if the object already exists and it works fine. but in case the object does not exist then I am having to make another request using update() to push the new object and make it available for later increments.
I want to be able to do only one request (e.g. findOne()) to get the user and then increment the field only if object exists in the array and if not I would like to push the new object instead. then save the document. this way I am only making one read/request from the database instead of two.
this is the function now:
async addItemToCart(body, userId) {
const itemInDb = await Model.findOneAndUpdate(
{
_id: userId,
'cart.productId': body.productId,
},
{ $inc: { 'cart.$.count': 1 } }
);
if (itemInDb) return true;
const updated = await Model.update(
{ _id: userId },
{ $push: { cart: body } }
);
if (updated.ok !== 1)
return createError(500, 'something went wrong in userService');
return true;
}
what I would like to do is:
async addItemToCart(body, userId) {
const itemInDb = await Model.findOne(
{
_id: userId,
'cart.productId': body.productId,
}
);
if (itemInDb) {
/**
*
* increment cart in itemInDb then do itemInDb.save() <<------------
*/
} else {
/**
* push product to itemInDb then save
*/
}
Thank you!

You can try findOneAndUpdate with upsert.
upsert: true then create data if not exists in DB.
Model.findOneAndUpdate(
{
_id: userId,
'cart.productId': body.productId,
},
{ $inc: { 'cart.$.count': 1 } },
{
upsert: true,
}
)
Use $set and $inc in one query.
try {
db.scores.findOneAndUpdate(
{
_id: userId,
'cart.productId': body.productId,
},
{ $set: { "cart.$.productName" : "A.B.C", "cart.$.productPrice" : 5}, $inc : { "cart.$.count" : 1 } },
{ upsert:true, returnNewDocument : true }
);
}
catch (e){
//error
}
reference Link : here

You can use upsert.
upsert is defined as an operation that creates a new document when no document matches the query criteria and if matches then it updates the document. It is an option for the update command. If you execute a command like below it works as an update, if there is a document matching query, or as an insert with a document described by the update as an argument.
Example: I am just giving a simple example. You have to change it according to your requirement.
db.people.update(
{ name: "Andy" },
{
name: "Andy",
rating: 1,
score: 1
},
{ upsert: true }
)
So in the above example, if the people with name Andy is found then the update operation will be performed. If not then it will create a new document.

delete object from document array in mongodb collection using mongoose

I try to remove an element from an array attribute of my object.
This is my schema :
const userSchema = new mongoose.Schema({
userID: {
type: Number
},
name: {
type: String
},
names: [
{
text: { type: String, required: true },
order: {
type: Number,
required: true
}
}
]
});
this is my mongoose function :
User.findOne({ userID: Number(req.params.id) })
.then((user) => {
user.names.remove({text: "john", order: 3});
recipe.save(() => {
res.json(recipe);
});
})
I don't understand why it's not good :/

As per documentation of mongoose remove method remove operation is only executed when a callback is passed. To force execution without a callback, you must first call remove() and then execute it by using the exec() method.
Since you are trying to delete from array of objects then better would be to use pull operator. You don't have to do find and remove, you can simply use update method.
As per documentation of $pull operator you can either specify a value or a condition
i.e.
{ $pull: { <field1>: <value|condition>, <field2>: <value|condition>, ... } }
In your scenario you need to either specify complete value of one or more names item object or an condition that matches one or more names item
Add the condition where you match id of names item or if you don't know that then you can use elemMatch to match on few fields i.e.
Use following pull condition to solve the issue:
User.update(
{ _id: Number(req.params.id) },
{ $pull: { 'names': { $elemMatch: { 'text': "john", 'order': 3 }} } },
(error, success) => {
if (error) console.log(error);
console.log(success);
}
);

To Remove Element from array in document please follow as below
User.update(
{
userID: Number(req.params.id),
},
{
$pull: { names: { $elemMatch: { text: "john", order: 3 } } }
},
{
multi: false
}
).lean().then((Status) => {
console.log("Status-->", Status);
res.json('Removed Successfully');
})
Refer $pull operator at link

Put Javascript Array Values into Mongodb Collection Values

I have a Javascript Array filled with mean Values and I want to insert them into a collection with a field named "mean". The Field "mean" already exists and has already values in them and now I want to update them with the values of the Array. To be more specific: I want the first Value of the Array to be in the first Document under the field "mean" and so on. I have 98 Documents and the Array has also a length of 98.
The Collection looks like this with the name "cmean":
{
"_id" : "000",
"mean" : 33.825645389680915
}
{
"_id" : "001",
"mean" : 5.046005719077798
}
and the Array:
[
33.89923155012405,
5.063347068609219
]

You can use the forEach method on the array to iterate it and update the collection. Use the index to get the _id to be used in the update query, something like the following:
meansArray.forEach(function(mean, idx) {
var id = db.cmean.find({}).skip(idx).limit(1).toArray()[0]["_id"];
db.cmean.updateOne(
{ "_id": id },
{ "$set": { "mean": mean } },
{ "upsert": true }
);
});
For large collections, you can streamline your db performance using bulkWrite as follows:
var ops = [];
meansArray.forEach(function(mean, idx) {
var id = db.cmean.find({}).skip(idx).limit(1).toArray()[0]["_id"];
ops.push({
"updateOne": {
"filter": { "_id": id },
"update": { "$set": { "mean": mean } },
"upsert": true
}
});
if (ops.length === 1000 ) {
db.cmean.bulkWrite(ops);
ops = [];
}
})
if (ops.length > 0)
db.cmean.bulkWrite(ops);

update({"_id": id}, $set: {"mean": myArray}, function(res, err) { ... });
If you are using mongoose, you also have to change data model from string to array.