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Mongoose - Deleting documents is unresponsive

I'm trying to use Mongoose (MongoDB JS library) to create a basic database, but I can't figure out how to delete the documents / items, I'm not sure what the technical term for them is.
Everything seems to work fine, when I use Item.findById(result[i].id), it returns a valid id of the item, but when I use Item.findByIdAndDelete(result[i].id), the function doesn't seem to start at all.
This is a snippet the code that I have: (Sorry in advance for bad indentation)
const testSchema = new schema({
item: {
type: String,
required: true
},
detail: {
type: String,
required: true
},
quantity: {
type: String,
required: true
}
})
const Item = mongoose.model("testitems", testSchema)
Item.find()
.then((result) => {
for (i in result) {
Item.findByIdAndDelete(result[i].id), function(err, result) {
if (err) {
console.log(err)
}
else {
console.log("Deleted " + result)
}
}
}
mongoose.connection.close()
})
.catch((err) => {
console.log(err)
})
I'm not sure what I'm doing wrong, and I haven't been able to find anything on the internet.
Any help is appreciated, thanks.

_id is a special field on MongoDB documents that by default is the type ObjectId. Mongoose creates this field for you automatically. So a sample document in your testitems collection might look like:
{
_id: ObjectId("..."),
item: "xxx",
detail: "yyy",
quantity: "zzz"
}
However, you retrieve this value with id. The reason you get a value back even though the field is called _id is because Mongoose creates a virtual getter for id:
Mongoose assigns each of your schemas an id virtual getter by default which returns the document's _id field cast to a string, or in the case of ObjectIds, its hexString. If you don't want an id getter added to your schema, you may disable it by passing this option at schema construction time.
The key takeaway is that when you get this value with id it is a string, not an ObjectId. Because the types don't match, MongoDB will not delete anything.
To make sure the values and types match, you should use result[i]._id.

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.

Mongodb version 3+: how to insert new document only if it doesn't exist and get the result

I have tried dozens of solutions, and none of these worked and most of them are deprecated.
I have a collection with documents like this:
_id: 5d99ef3285c93711828cd15d
code: 1234
name: "Foo"
surname: "Bar"
address: "That street"
phone: 1234567
I would like to insert new document only if there isn't any document with the same code.
My last try was this:
const result = await db.collection('users').findOneAndUpdate(
{ code: user.code },
{
$setOnInsert: user,
},
{
upsert: true,
}
);
but I get E11000 duplicate key error collection...
updateOne() returns the same error; update() is deprecated...
So, how to add only new document and get the result (true if document has been added or false if it already exists)?
Thank you.

As far as my knowledge is,
with $set and $setOnInsert, we can not update/insert the same field.
i.e. $set and $setOnInsert should be mutually exclusive.
It works if the document is being updated, but throws an exception if document is being inserted.
In case of update, $setOnInsert will be ignored.
In case of insertion, both will be executed.
I think the solution would be,
use returnNewDocument and have one field in the schema isUpdated defaults to false.
Note:
make sure whenever you use "insert" operation on the collection, you don't add isUpdated which will be set to false then or set it to false.
form a query like
db.collection('users').findOneAndUpdate(
{ code: user.code },
{
$set: user, // which has user.isUpdated set to true
},
{
upsert: true,
returnNewDocument: false, // (by default it is false only)
}
);
With this logic,
So let's go step by step,
If the document doc1 is not present, it will be inserted, and mongo will return the response null. You will know, it is Inserted.
If the document doc2 is present(considering this logic is not applied on the previously inserted document doc2 before and isUpdated field is not present in doc2), it will execute $set so in returned cursor, this field not present i.e. undefined, so you know from this, it is updated.
let's say we fire the same query for doc1 again (which is present and we have applied our new logic), then there are two cases
a. it will be updated and in the cursor, we have isUpdated equal to false.
b. it will be updated and in the cursor, we have isUpdated equal to true.
In both case you know it is Updated
I think this approach should solve your problem.
Please share if this helps you, or you find any other solution.
UPDATE
ACTUALLY
You dont even need another field isUpdated, without this fiels this should work with the same logic.
i.e. If cursor is null then its inserted, if not null then its updated.

You can still run a query like this;
document = db.collection('users').findOne({code:userCode});
if(document == null){
//document doesn't exists so you can use insertOne
}
else{
// document exists, sou you can update
}
it won't be efficient but it'll do the work.

You can simply wrap the request with a try/catch block to catch the Error. Then return false when this exception occured.

You could use findOne to see if a user with that code exists first
const result = await db.collection('users')
.findOne({ code: user.code });
if( result ){
return res
.status(400)
.json({ errors: [{ msg: 'User already exists' }] });
}
//create
user = new User({
code = code,
name = name,
foo = foo
)}
//save
user.save();
res.json(user);

Try this one
db.collection("users").findOne({ code: user.code }, (err, data) => {
if (data) {
return res.send(false);
} else {
// a document
var user = new User({
code: code,
name: "Foo",
surname: "Bar",
address: "That street",
phone: 1234568
});
// save model to database
user.save(function(err, book) {
if (err) return console.error(err);
return res.send(true);
});
}
});

Users.findOneAndUpdate({code:user.code}, {upsert: true, new: true, setDefaultsOnInsert: true }, function(error, result) { if (error) return; // do something with the document }).
I think it would work. Let us know if you have any questions.

Push "programmatic" array to an Object's array property

I'm building a Thesaurus app, and for this question, the key note is that i'm adding a list of synonyms(words that have the same meaning) for a particular word(eg - "feline", "tomcat", "puss" are synonyms of "cat")
I have a Word object, with a property - "synonyms" - which is an array.
I'm going to add an array of synonyms to the Word synonyms property.
According to the MongoDb documentation see here, the only way to append all the indexes of an array to a document's array property at once is to try the following:
db.students.update(
{ _id: 5 },
{
$push: {
quizzes: {
$each: [ { wk: 5, score: 8 }, { wk: 6, score: 7 }, { wk: 7, score: 6 } ],
}
}
}
)
Let's re-write that solution to suit my data, before we venture further.
db.words.update(
{ baseWord: 'cat' },
{
$push: {
synonyms: {
$each: [ { _id: 'someValue', synonym: 'feline' }, { _id: 'someValue', synonym: 'puss' }, { _id: 'someValue', synonym: 'tomcat' } ],
}
}
}
)
Nice and concise, but not what i'm trying to do.
What if you don't know your data beforehand and have a dynamic array which you'd like to feed in?
My current solution is to split up the array and run a forEach() loop, resulting in an array being appended to the Word object's synonyms array property like so:
//req.body.synonym = 'feline,tomcat,puss';
var individualSynonyms = req.body.synonym.split(',');
individualSynonyms.forEach(function(synonym) {
db.words.update(
{ "_id": 5 },
{ $push: //this is the Word.synonyms
{ synonyms:
{
$each:[{ //pushing each synonym as a Synonym object
uuid : uuid.v4(),
synonym:synonym,
}]
}
}
},{ upsert : true },
function(err, result) {
if (err){
res.json({ success:false, message:'Error adding base word and synonym, try again or come back later.' });
console.log("Error updating word and synonym document");
}
//using an 'else' clause here will flag a "multiple header" error due to multiple json messages being returned
//because of the forEach loop
/*
else{
res.json({ success:true, message:'Word and synonyms added!' });
console.log("Update of Word document successful, check document list");
}
*/
});
//if each insert happen, we reach here
if (!err){
res.json({ success:true, message:'Word and synonyms added!.' });
console.log("Update of Word document successful, check document list");
}
});
}
This works as intended, but you may notice and issue at the bottom, where there's a commented out ELSE clause, and a check for 'if(!err)'.
If the ELSE clause is executed, we get a "multiple headers" error because the loop causes multiple JSON results for a single request.
As well as that, 'if(!err)' will throw an error, because it doesn't have scope to the 'err' parameter in the callback from the .update() function.
- If there was a way to avoid using a forEach loop, and directly feed the array of synonyms into a single update() call, then I can make use of if(!err) inside the callback.
You might be thinking: "Just remove the 'if(!err)' clause", but it seems unclean to just send a JSON response without some sort of final error check beforehand, whether an if, else, else if etc..
I could not find this particular approach in the documentation or on this site, and to me it seems like best practice if it can be done, as it allows you to perform a final error check before sending the response.
I'm curious about whether this can actually be done.
I'm not using the console, but I included a namespace prefix before calling each object for easier reading.

There is not need to "iterate" since $each takes an "array" as the argument. Simply .map() the produced array from .split() with the additional data:
db.words.update(
{ "_id": 5 },
{ $push: {
synonyms: {
$each: req.body.synonym.split(',').map(synonym =>
({ uuid: uuid.v4, synonym })
)
}
}},
{ upsert : true },
function(err,result) {
if (!err){
res.json({ success:true, message:'Word and synonyms added!.' });
console.log("Update of Word document successful, check document list");
}
}
);
So .split() produces an "array" from the string, which you "transform" using .map() into an array of the uuid value and the "synonym" from the elements of .split(). This is then a direct "array" to be applied with $each to the $push operation.
One request.