Passing Dynamic Mongoose query into db.collection.find() - javascript

I have a client side application that I would like to have the ability to specify arbitrary queries to MongoDB through a server side call to a query function.
I have tried multiple arrangements on both my client and server to try to make this work but I can't seem to figure out the correct way to go about this.
This is an example request that my client would send (although the goal is for the query property to be any valid query that one could hardcode on the server side):
"collectionName": "abilities",
"query": "{\"_id\":{\"$in\":[5,{\"$oid\":\"619f97d1d977f089ac559368\"}]}}"
On the server side, I've parsed the query with EJSON to try and get it to a state where I can pass it into the db.collection.find() method but the return type is not compatible (I recieve: EJSON.SerilizbleType vs I need: Filter<Document>)
Another thought I had was to stringify the EJSON result and then convert it to JSON through JSON.parse(). If I console.log() the result, I get the following:
{ _id: { '$in': [ 5, '619f97d1d977f089ac559368' ] } }
Passing that into the find() method produces no results.
If I console.log() the parsed text, I receive the following:
_id: { '$in': [ new Int32(5), new ObjectId("619f97d1d977f089ac559368") ] }
Which shows that the JSON conversion is losing the type, which is important when constructing the query.
Thoughts on how I may go about this?


Sending an array with axios.get as params is undefined

I am making a get request with additional params options, since I am using that request on a filter, so the params are filters for what to get back:
const res = await axios.get("http://localhots:3000/getsomedata", {
params: {
firstFilter: someObject,
secondFilter: [someOtherObject, someOtherObject]
The request goes through just fine, on the other end, when I console.log(req.query); I see the following:
firstFilter: 'someObject',
'secondFilter[]': ['{someOtherObject}', '{someOtherObject}'],
If I do req.query.firstFilter that works just fine, but req.query.secondFilter does not work and in order for me to get the data, I have to do it with req.query["secondFilter[]"], is there a way to avoid this and be able to get my array of data with req.query.secondFilter?
My workaround for now is to do:
const filter = {
firstFilter: req.query.firstFilter,
secondFilter: req.query["secondFilter[]"]
And it works of course, but I don't like it, I am for sure missing something.
Some tools for parsing query strings expect arrays of data to be encoded as array_name=1&array_name=2.
This could be a problem if you have one or more items because it might be an array or might be a string.
To avoid that problem PHP required arrays of data to be encoded as array_name[]=1&array_name[]=2 and would discard all but the last item if you left the [] out (so you'd always get a string).
A lot of client libraries that generated data for submission over HTTP decided to do so in a way that was compatible with PHP (largely because PHP was and is very common).
So you need to either:
Change the backend to be able to parse PHP style
Change your call to axios so it doesn't generate PHP style
The specifics depend what backend you are using, but it looks like you might be using Express.js.
See the settings.
You can turn on Extended (PHP-style) query parsing by setting it to "extended" (although that is the default)
const app = express()
app.set("query parser", "extended");
The axios documentation says:
// `paramsSerializer` is an optional function in charge of serializing `params`
// (e.g.,
paramsSerializer: function (params) {
return Qs.stringify(params, {arrayFormat: 'brackets'})
So you can override that
const res = await axios.get("http://localhots:3000/getsomedata", {
params: {
firstFilter: someObject,
secondFilter: [someOtherObject, someOtherObject]
paramsSerializer: (params) => Qs.stringify(params, {arrayFormat: 'repeat'})
My example requires the qs module
This has to do with params not being serialized correctly for HTTP GET method. Remember that GET has no "body" params similar to POST, it is a text URL.
For more information I refer to this answer, which provides more detailed info with code snippets.

Using MongoDB Stitch webhook service function, how can I convert the returned "insertedId" to string?

I'm creating MongoDB Stitch http services (using the 3rd Party Services > Incoming Webhooks > Function Editor) for a simple CRUD application and I am trying to insertOne() document and then return the document id as a string.
The insertion works as expected and I await the result and store it in a variable.
const result = await collection.insertOne(payload.query)
const id = result.insertedId
The problem is trying to convert this id to string. I'm guessing it's due to my lack of understanding the MongoDB Extended JSON and BSON types, etc. I've read all parts of the documentation that I thought could provide a solution here.
I've tried the following to convert the return value to a string:
id.toString() // logs as a string, but is an object { $oid: '507c7f79bcf86cd7994f6c0e' }
id.valueOf() // logs as a string, but is an object { $oid: '507c7f79bcf86cd7994f6c0e' }
id['$oid'] // undefined
Object.values(id.insertedId) // throws error: {"message":"'values' is not a function"}
id.str // undefined
result.str // undefined
Not sure what else to try and would really appreciate if someone can point me in the right direction here to provide a solution.
Thank you in advance.
Found a solution after noticing this section of the documentation:
MONGODB STITCH > Functions > Reference > JSON & BSON
const result = await collection.insertOne(payload.query)
const id = JSON.stringify(
Seems a bit hacky just for getting the id of the document into a string, but it will work for now.

Write an object containing an array of objects to a mongo database in Meteor

In my user collection, I have an object that contains an array of contacts.
The object definition is below.
How can this entire object, with the full array of contacts, be written to the user database in Meteor from the server, ideally in a single command?
I have spent considerable time reading the mongo docs and meteor docs, but can't get this to work.
I have also tried a large number of different commands and approaches using both the whole object and iterating through the component parts to try to achieve this, unsuccessfully. Here is an (unsuccessful) example that attempts to write the entire contacts object using $set:
Meteor.users.update({ _id: this.userId }, {$set: { 'Contacts': contacts}});
Thank you.
Object definition (this is a field within the user collection):
"Contacts" : {
"contactInfo" : [
"phoneMobile" : "1234567890",
"lastName" : "Johnny"
"firstName" : "Appleseed"
This update should absolutely work. What I suspect is happening is that you're not publishing the Contacts data back to the client because Meteor doesn't publish every key in the current user document automatically. So your update is working and saving data to mongo but you're not seeing it back on the client. You can check this by doing meteor mongo on the command line then inspecting the user document in question.
if (this.userId) return Meteor.users.find(this.userId, { fields: { profile: 1, Contacts: 1 }});
The command above is correct. The issue is schema verification. Simple Schema was defeating the ability to write to the database while running 'in the background'. It doesn't produce an error, it just fails to produce the expected outcome.

Best practices for dealing with ObjectId with mongo and Javascript

I am developing an app with Mongo, Node.JS and Angular
Every time the object is delivered and handled in the front-end, all objectId's are converted to strings (this happens automatically when I send it as json), but when when I save objects back into mongo, I need to convert _id and any other manual references to other collections back to ObjectID objects. If I want to nicely separate database layer from the rest of my backend, it becomes even more messy, lets assume my database layer has the following signature:
database.getItem(itemId, callback)
I want my backend business treat itemId as opaque type (i.e no require'ing mongo or knowing anything about ObjectId outside of this database layer), yet at the same time I want to be able to take the result of this function and send it directly to
the frontend with express js.
exports.getItem = function(req, res) {
database.getItem(, function(err, item) {
What I end up doing now is:
exports.getItem = function(itemId, callback) {
if (typeof itemId == 'string') {
itemId = new ObjectID(itemId);
var query = {_id: itemId};
items.findOne(query, callback);
This way it can handle both calls which come from within the backend, where itemId reference might be coming from another object and thus might already be in the right binary format, as well as requests with string itemId's.
As I already mentioned above, when I am saving an object that came from front-end and which contains many manual references to other collections that is even more painful, since I need to go over the object and change all id strings to ObjectIds.
This all feels very wrong, there must be a better way to do it. What is it?

node.js how to handle change of objects and variables in callbacks

I have just started a large project with node.js and I have stumbled upon some callback nightmare issues. I have done some node.js development before, but only small stuff based on tutorials.
I have a user model and a owner model, who is the owner for that user...basically the part I am building in node.js will be a REST service so I need to send a json containing a user and it's owner name. My problem is trying to get the owner name like I would do it in ruby or php and setting it as a property..but it doesn't work.
How do people handle this kind of logic in node.js where you need to change objects in callback functions? Also I do not want it to affect performance.
I am using mysql as the database because this was a requirement. So the code is this:
//find all
'id' :
}, function(err, users) {
if (err) console.log(err); //do something better here
else {
var json = [];
users.forEach(function(user) {
user.getOwner(function(err, owner) {
user.accountOwner =;
I want to send something like this:
'username": user.username,
The problem is you are not understanding the control flow of node code. It doesn't go line by line top to bottom in chronological order. So your issue is your res.send(json) happens BEFORE (in time) your user.getOwner callback executes, so you send your empty json, then you stuff things into the json array after it's already been sent. You need to use something like async.each to do your joins, wait for all of the user`s owners to be populated, and then send the response. Or you could actually let the database join the data by writing a SQL join instead of doing N+1 queries against your database.