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Unable to remove item from array using Mongoose / UpdateOne

I have a Node.js application in which I am trying to remove an object from an array when an API endpoint is hit. I so far have been unable to get it to update/remove the object. Currently, the below query returns with no error but upon checking into my DB I am still seeing it. Below is my query and basic response (I will be adding more but that is outside the scope of this question). I have also included a sample of my data model.
In the below data model I am trying to remove the whole object from the foo array as it is no longer needed.
Code
const ID = req.params.id
await FooBar.updateOne({foo: {$elemMatch: {v_code: ID}}}, { $pull: {v_code: ID}}, (err) => {
if(err) return res.json({success: false, err})
return res.json({success: true, id: ID})
})
Data model
{
bar: [
{
foo: [
{
v_code: <>
_id: <>
}
]
}
]
}
I'm sure this has been asked for in other questions but none specific to my data model. I've tried piecing together multiple SO posts and that is how I got the $elemmatch and the $pull portions of my query and so far I've had zero luck

give the following command a try:
db.collection.updateOne(
{
"bar.foo.v_code": ID
},
{
$pull: { bar: { foo: { $elemMatch: { v_code: ID } } } }
}
)
https://mongoplayground.net/p/iqJki-mnHSJ

Meteor MongoDB Setting field of array per document

I have a Documents in a Collection that have a field that is an Array (foo). This is an Array of other subdocuments. I want to set the same field (bar) for each subdocument in each document to the same value. This value comes from a checkbox.
So..my client-side code is something like
'click #checkAll'(e, template) {
const target = e.target;
const checked = $(target).prop('checked');
//Call Server Method to update list of Docs
const docIds = getIds();
Meteor.call('updateAllSubDocs', docIds, checked);
}
I tried using https://docs.mongodb.com/manual/reference/operator/update/positional-all/#positional-update-all
And came up with the following for my Server helper method.
'updateAllSubDocs'(ids, checked) {
Items.update({ _id: { $in: ids } }, { $set: { "foo.$[].bar": bar } },
{ multi: true }, function (err, result) {
if (err) {
throw new Meteor.Error('error updating');
}
});
}
But that throws an error 'foo.$[].bar is not allowed by the Schema'. Any ideas?
I'm using SimpleSchema for both the parent and subdocument
Thanks!

Try passing an option to bypass Simple Schema. It might be lacking support for this (somewhat) newer Mongo feature.
bypassCollection2
Example:
Items.update({ _id: { $in: ids } }, { $set: { "foo.$[].bar": bar } },
{ multi: true, bypassCollection2: true }, function (err, result) {
if (err) {
throw new Meteor.Error('error updating');
}
});
Old answer:
Since you say you need to make a unique update for each document it sounds like bulk updating is the way to go in this case. Here's an example of how to do this in Meteor.
if (docsToUpdate.length < 1) return
const bulk = MyCollection.rawCollection().initializeUnorderedBulkOp()
for (const myDoc of docsToUpdate) {
bulk.find({ _id: myDoc._id }).updateOne({ $set: update })
}
Promise.await(bulk.execute()) // or use regular await if you want...
Note we exit the function early if there's no docs because bulk.execute() throws an exception if there's no operations to process.

If your data have different data in the $set for each entry on array, I think you need a loop in server side.
Mongo has Bulk operations, but I don't know if you can call them using Collection.rawCollection().XXXXX
I've used rawCollection() to access aggregate and it works fine to me. Maybe work with bulk operations.

How to update MongoDB with no duplicates

I'm using Meteor framework with Blaze. How can I fetch data from an API and only insert new data in my MongoDB collection and not duplicates?
Fetching data from the API.
if (Meteor.isServer) {
Meteor.methods({
fetchApiData: function () {
this.unblock();
return Meteor.http.call('GET','http://jsonplaceholder.typicode.com/posts');},
Insert data into database:
populateDatabaseApi: function () {
Meteor.call('fetchApiData', function(error, result) {
myCollection.insert({
//upsert: true,
A: result.data.title,
B: result.data.userId,
C: result.data.id });
});
},
When using "myCollection.update" with "upsert: true" it does not insert new entries obviously. What is best practice to go about checking the API for data and inserting ONLY new entries with no duplicates and updating existing entries?
Thank you.

here's how i handle what i call reference data at startup. it's driven off of JSON data. you have to pick a field that serves as your "reference" for each JSON object, so you can see if it's already in the db.
_.each(ItemData.items, function(q) {
check(q, ItemsSchema);
Items.upsert({
item: q.item
}, {
$set: {
item: q.item,
}
}, function(error, result) {
if (error) {
let errMsg = 'Error while writing item data';
console.error(errMsg, error);
throw new Meteor.Error('500', errMsg);
}
});
});
i use an upsert to handle insert vs update.

I'm not familiar with your specific framework, so I can't help with syntax, but you should be able to find all documents with the same properties as the document you're trying to insert (there should be only one). If there is one, then save it using upsert. If there isn't, then the object you're saving is unique, and you should save a new one.

Using only "vanilla" Meteor, assuming your api object have unique ids and that you have the proper data access (ie, if item exist findOne would find it), I'd use :
populateDatabaseApi: function () {
Meteor.call('fetchApiData', function(error, result) {
var item = myCollection.findOne({A : result.data.id})
if(item){
//do nothing, this item already is in the db
}else{
myCollection.insert({
A: result.data.title,
B: result.data.userId,
C: result.data.id });
});
}
},

Update a row in nedb

I have the following data in nedb.
["UserId":"1446943507761","UserName":"xxx","link":"xxx.html","taskDone":"false","id":14,"_id":"fdaaTWSxloQZdYlT"]
["UserId":"1446943507761","UserName":"xxx","link":"xxx.html","taskDone":"false","id":1,"_id":"fzh2cedAXxT76GwB"]
["UserId":"1446943507761","UserName":"xxx","link":"xxx.html","taskDone":"false","id":0,"_id":"k4loE7XR5gioQk54"]
I am trying to update row with id 0 and set the value of taskDone to true. I use the following query to set the value to true
db.taskmap.update({ _id: "k4loE7XR5gioQk54", UserName:"xxx" }, { $set: { taskDone: "true"} }, function (err, numReplaced) {
console.log("replaced---->" + numReplaced);
});
It updates the value but it updates as a new row. It basically inserts a new row with same values except for the taskdone value as true. It does not delete the existing data. Hence in the final data table after update i get tow rows for id 0 with all values same except for the taskDone. I am not sure if i am doing anything wrong. It will be helpful if anybody can tell me a correct way of updating the value.

You should call db.loadDatabase(); again at the end of db.update(); to see, that no second row with the same _id: appears instead the specific doc gets directly updated.
Edit:
It appears that sometimes when you do db.update() the document that should be updated appears twice instead on the database. It happened to me when I was updating an entry in a list of servers, multiple entries with the modified values were appearing on the database. So to avoid this simply do the following. (I took the same code that was suggested as the answer)
db.update(
{ _id: "k4loE7XR5gioQk54", UserName:"xxx" },
{ $set: { taskDone: "true"} },
{},// this argument was missing
function (err, numReplaced) {
console.log("replaced---->" + numReplaced);
db.loadDatabase();
}
);
Doing this prevents this from happening. I tested it multiple times and the issue disappeared.

update wants four arguments
var Datastore = require('nedb');
var db = new Datastore();
db.insert(
[
{
"UserId":"1446943507761",
"UserName":"xxx",
"link":"xxx.html",
"taskDone":"false",
"id":14,
"_id":"fdaaTWSxloQZdYlT"
},
{
"UserId":"1446943507761",
"UserName":"xxx",
"link":"xxx.html",
"taskDone":"false",
"id":1,
"_id":"fzh2cedAXxT76GwB"
},
{
"UserId":"1446943507761",
"UserName":"xxx",
"link":"xxx.html",
"taskDone":"false",
"id":0,
"_id":"k4loE7XR5gioQk54"
}],
function (err, newDocs) {
// empty here
}
);
db.update(
{ _id: "k4loE7XR5gioQk54", UserName:"xxx" },
{ $set: { taskDone: "true"} },
{},// this argument was missing
function (err, numReplaced) {
console.log("replaced---->" + numReplaced);
}
);
// should give the correct result now
db.find({}).exec(function (err, docs) {console.log(docs);});

mongoose update array ObjectId from an array from angular

I'm adding ObjectId to an array from another array that I receive as the body.
exports.updateBasket = function (req, res) {
Basket.findOne({ _id: req.params.id }, function (err, basket) {
for(var i=0, len=req.body.length; i < len; i++) {
basket.update({$addToSet: { "items": req.body[i] } }, { upsert: true, safe: true });
}
if (err) {
res.send(err);
}
else {
res.json({ message: 'Successfully added' });
}
});
};
I have 2 questions concerning this :
Is there any upside to do the loop in angular and have multiple PUT?
What is the way to update this same array but when removing ObjectId?
One way that I thought of was to loop ObjectId that have to be removed and look if they are in the array of the object, if yes, delete them.
Another way would be to clear the array when PUT is called and update with the new ObjectId list (which would be the ones that were there minus the one user removed).
Both doesn't feel right ...
thanks

You code looks a bit odd. You are fetching asynchronously on the req.params._id but you are queuing up req.body.length potential worth of updates, but you send 'success' before you even get a response back from the updated results.
If you wanted to filter on arrays, look at lodash, if you want to process multiple updates asynchronously and get those response use async modules.