Develop Reference

How to populate a nested path using aggregate?

I have been trying to find the averageSum and averageRating, but I cannot get it done because I do not know how to populate using aggregate or if there is a work around. I have heard of $lookup, but I am not sure how to do it, also it tells me something about atlas tier does not do it. Is there a another way around to this? Can I populate then aggregate or can I find the averageSum and averageRating at the end using another method? Please help me
here is how my schema looks:
const favoriteSchema = new mongoose.Schema({
user: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
favoriteSellers: [
//create array of object id, make sure they are unique for user not to add multiple sellers
{
type: mongoose.Schema.Types.ObjectId,
ref: "Seller",
unique: true,
},
],
});
and here is my Seller schema:
const sellerSchema = new mongoose.Schema({
user: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
business: businessSchema,
sellerType: [String],
reviews: [
{
by: {
type: mongoose.Schema.Types.ObjectId,
ref: "User",
unique: true,
},
title: {
type: String,
},
message: {
type: String,
},
rating: Number,
imagesUri: [String],
timestamp: {
type: Date,
default: Date.now,
},
},
],
...
});
So I have an array of favorite sellers, I want to populate the sellers, then populate the reviews.by and user paths, and then do the calculation for the average sum and do the average rating. If possible please help me. What are my options here? Just do it outside on the expressjs route logic?
Here is my aggregate:
aggregatePipeline.push({
$match: { user: req.user._id },
});
//****** Here is where I want to populate before start the rest **********
then continue to following code because the fields(paths) are not populated so it averageSum will be 0 at all times.
aggregatePipeline.push({
$addFields: {
ratingSum: {
$reduce: {
initialValue: 0,
input: "$favoriteSellers.reviews",
in: { $sum: ["$$value", "$$this.rating"] },
},
},
},
});
//get average of rating ex. seller1 has a 4.5 averageRating field
aggregatePipeline.push({
$addFields: {
averageRating: {
$cond: [
{ $eq: [{ $size: "favoriteSellers.reviews" }, 0] }, //if it does not have any reviews, then we will just send 0
0, //set it to 0
{
$divide: ["$ratingSum", { $size: "$reviews" }], //else we can divide to get average Rating
},
],
},
},
});
let favList = await Favorite.aggregate(aggregatePipeline).exec();
When I retrieve my code, the array looks like:
[
{
_id: new ObjectId("62a7ce9550094eafc7a61233"),
user: new ObjectId("6287e4e61df773752aadc286"),
favoriteSellers: [ new ObjectId("6293210asdce81d9f2ae1685") ],
}
]
Here is a sample on how I want it to look:
(so each seller should have a field of average rating like and averageSum)
_id: 'favorite_id.....'
user: 'my id',
favoriteSellers:[
{
_id: 'kjskjhajkhsjk',
averageRating: 4.6
reviews:[.....],
...
},
{
_id: 'id______hsjk',
averageRating: 2.6
reviews:[.....],
...
},
{
_id: 'kjid______khsjk....',
averageRating: 3.6
reviews:[.....],
...
}
]

How to query a mongo document using mongoose?

MongoDB documents contain an array of objects and what is the best way to query those documents if I want to find and remove an object from an array with some specific value;
Here is an example of the document schema
const mongoose = require("mongoose");
const LibrarySchema = new mongoose.Schema({
user: {
type: mongoose.Schema.Types.ObjectId,
required: true,
},
books: [
{
type: new mongoose.Schema({
bookName: {
type: String,
required: true,
},
chapterReading: {
type: Number,
default: 1,
required: true,
},
}),
},
],
});
const Library = mongoose.model("Library", LibrarySchema);
exports.Library = Library;
If I want to find and remove a book with some bookName

Use $pull
Example :
Library.update({}, { $pull: { books: { bookName: "Yourbookname" } } })

use mongooseModel.find() on schema that has a Schema.Types.Mixed property

I have trouble using postModel.find() query in a schema that defined as Schema.Types.Mixed.
this is a sample of my schema
const PostSchema = new mongoose.Schema({
//.....
address: {
type: String,
required: true,
},
postDetails: {
type: Schema.Types.Mixed,
required: true,
},
author: {
type: Schema.Types.ObjectId,
ref: 'User',
},
//.....
});
this is a sample document stored in db
{
//.....
"state": "Lakes State",
"address": "some address",
"postDetails": {
"type": "Cages",
"condition": "Used"
},
//......
}
it is giving me an empty array if I use this
const queryObject = {
postDetails: {
type: 'Cages',
},
};
return this.postModel.find(queryObject);
but it gives the desired results if I include all the properties like this
const queryObject = {
postDetails: {
type: 'Cages',
condition: 'Used',
},
};
return this.postModel.find(queryObject);
How do i get all matching posts that have postDetails.type = 'Cages' ? without knowing all available properties inside postDetails
there are some similar questions about this here. but most of them are using arrays instead of an object

You can use dot notation for querying embedded documents
postModel.find({
"postDetails.type": "Cages"
});

Push To Mongoose Subdocuments

Hello I am creating a series of groupings describing the roles certain users are taking within the context of helping a client. The object in the Prospect model is called caseworkers. In caseworkers is a series of arrays for the different types of roles done. The equation is to allow the user to push his info as a subdocument called CaseWorker. Basically creating an object with 6 arrays that users can push to. Ive tried a few things and settled on Subdocuments. Any help would be awesome.
Here is my code:
const mongoose = require("mongoose");
const CaseWorker = require("./CaseWorker");
const ProspectSchema = mongoose.Schema({
caseWorkers: {
originators: [CaseWorker.schema],
loanProcessors: [CaseWorker.schema],
documentProcessors: [CaseWorker.schema],
upsells: [CaseWorker.schema],
primaryReso: [CaseWorker.schema],
taxPreparers: [CaseWorker.schema],
secondaryReso: [CaseWorker.schema],
}
module.exports = mongoose.model("prospect", ProspectSchema);
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const CaseWorkerSchema = new Schema({
name: {
type: String,
required: true,
},
email: {
type: String,
required: true,
unique: true,
},
role: { type: String },
resoCred1: { type: String },
resoCred2: { type: String },
reminders: [
{
_id: { type: mongoose.Schema.Types.ObjectId, ref: "User" },
userReminded: { type: mongoose.Schema.Types.ObjectId },
reminderDate: { type: Date },
reminderDueDate: { type: Date },
status: { type: String },
daysTilDue: { type: Number },
id: { type: String },
text: { type: String },
clientId: { type: mongoose.Schema.Types.ObjectId, ref: "Prospect" },
},
],
});
module.exports = mongoose.model("caseWorker", CaseWorkerSchema);
router.put("/:_id/caseWorkers/loanProcessors", auth, async (req, res) => {
const prospect = await Prospect.findByIdAndUpdate(req.params._id, {
"$push": {
"loanProcessors": {
"caseWorker": {
"name": req.body.name,
"email": req.body.email,
"role": req.body.role,
"resoCred1": req.body.resoCred1,
"resoCred2": req.body.resoCred2,
},
},
},
});
res.json(prospect);
console.log(prospect);
});

In your approach when updating the document you put caseWorker under loanProcessors but it's declared in the schema the other way around.
To update a nested object you have to use the dot notation to reference the field.
Don't forget to put the object key that represent the field as a string like this "caseWorkers.loanProcessors", because caseWorkers.loanProcessors is an invalid object key in javascript
"$push": {
"caseWorkers.loanProcessors": {
"name": req.body.name,
"email": req.body.email,
"role": req.body.role,
"resoCred1": req.body.resoCred1,
"resoCred2": req.body.resoCred2,
},
},

Can't get populate() to fill out array in Mongoose

Let me begin by saying I know that this seems to be a frequently asked question and I've spent a couple of days trying to figure it out but no answer seems to work so I'm trying on here.
I have two models, User and Chapter: a Chapter can have have many members (Users). When I do router.get('/chapters') I want to see an array of all the Users associated with a Chapter as a property along with the other Chapter properties, like so:
[
{
"leads": [],
"members": [
{"_id":"someString1","firstName":"...", "lastName":"..."},
{"_id":"someString2","firstName":"...", "lastName":"..."},
],
"date": "2018-12-12T15:24:45.877Z",
"_id": "5c11283d7d13687e60c186b3",
"country": "5c11283d7d13687e60c185d6",
"city": "Buckridgestad",
"twitterURL": "qui",
"bannerPic": "http://lorempixel.com/640/480/people",
"__v": 0
}
]
But what I'm getting is this:
[
{
"leads": [],
"members": [],
"date": "2018-12-12T15:24:45.877Z",
"_id": "5c11283d7d13687e60c186b3",
"country": "5c11283d7d13687e60c185d6",
"city": "Buckridgestad",
"twitterURL": "qui",
"bannerPic": "http://lorempixel.com/640/480/people",
"__v": 0
}
]
These are my Schemas:
Chapter
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
// Create Schema
const ChapterSchema = new Schema({
country: {
type: Schema.Types.ObjectId,
ref: "countries"
},
city: {
type: String,
required: true
},
leads: [
{
type: Schema.Types.ObjectId,
ref: "users"
}
],
members: [
{
type: Schema.Types.ObjectId,
ref: "users"
}
],
twitterURL: {
type: String,
required: true
},
bannerPic: {
type: String,
required: true
},
date: {
type: Date,
default: Date.now()
}
});
module.exports = Chapter = mongoose.model("chapters", ChapterSchema);
User
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
// Create Schema
const UserSchema = new Schema({
username: {
type: String,
required: true
},
firstName: {
type: String,
required: true
},
lastName: {
type: String,
required: true
},
organisation: {
type: String,
required: true
},
chapter: {
type: Schema.Types.ObjectId,
ref: "chapters"
},
email: {
type: String,
required: true
},
admin: {
type: Boolean,
default: false
},
lead: {
type: Boolean,
default: false
},
password: {
type: String,
required: true
},
date: {
type: Date,
default: Date.now()
}
});
module.exports = User = mongoose.model("users", UserSchema);
Like I said, when I call the endpoint, I want it to return me all the Chapters with all the Users as a populated property.
I've tried a lot of variations of .populate() but to know luck. The closest I got was going through the early levels of callback hell which I know isn't necessary with today's tech, but nothing is working!
My routes/api/chapters.js
// #route GET api/chapters
// #desc Get all Chapters
// #access Public
router.get("/", (req, res) => {
Chapter.find()
.populate("members")
.then(chapters => {
return res.json(chapters);
})
.catch(err =>
res.status(404).json({ nochaptersfound: "No Chapters found" })
);
});
I can get it to work the other way around:
My routes/api/users.js
// #route GET api/users
// #desc Return all users
// #access Public
router.get("/", (req, res) => {
User.find()
.populate("chapter")
.exec()
.then(users => res.status(200).json(users))
.catch(err => console.log(err));
Returns a user with the populated Chapter, but I can't populate the chapter.members array
Any help would be greatly appreciated!
Thanks!!

From your comment, I believe you are not actually storing users in your chapters. What you are doing is this:
User.create({..., chapter: id})...
And assuming chapter now has a user. Its not the way it works with mongoose, so if you want to actually save in both place, you will need to do it yourself. You are thinking about this as if it were a relational database
You will need to do something like:
const user = await User.create({..., chapter: id})
const chapter = await Chapter.findOne({ _id: id })
chapter.members.push(user)
chapter.save()
If your populate wasn't working, you'd not get an empty array, you'd get an array with ids. Your current populate query is fine, you just don't have any data to populate
With promises, it would look like this:
var userPromise = User.create({..., chapter: id}).exec()
var chapterPromise = Chapter.findOne({ _id: id }).exec()
Promise.all([userPromise, chapterPromise]).then((user, chapter) => {
chapter.members.push(user)
return chapter.save()
}).then(chapter => {
// send response
})
If you need 10 chapters with 10 to 50 users, I'd create 50 users, then push all of them into the chapters and save the chapter.