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Mongoose Database populate issue

This is the code
app.get("/cart", checkAuthentication, function (req, res) {
Orders.find({ user: req.user._id })
.populate('user')
.populate('order')
.exec((err, orders) => {
console.log(orders);
if (err) {
console.log("ERROR /cart :\n" + err);
res.redirect("/");
} else {
const OrderList = [];
orders.forEach((order) => {
const obj = {
order: order.order,
id: order._id
}
OrderList.push(obj);
});
var sum=0
OrderList.forEach(function(item){
sum += item.order.price
});
req.session.sum = sum;
req.session.orders = OrderList;
res.render("cart", { itemList: OrderList, login: true, name: req.user.name });
// res.render("cart", { itemList: OrderList, login: false, name: "abc" });
}
});
});
This is order model =>
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const orderSchema = new Schema({
user: { type: Schema.Types.ObjectId, ref: "User" },
order: { type: Schema.Types.ObjectId, ref: "SellingItem" },
date: { type: Date, default: Date.now }
});
module.exports = mongoose.model("Orders", orderSchema);
THIS IS THE ERROR
ERROR(null)
This is the github link for my repo - https://github.com/Paras0750/Bakery_Website/
I am trying to populate orders field but it is showing null.

You are importing csv file with _id value. It will become string in the database instead of ObjectId. That's why it cannot populate. Your code is correct.

How do I add new object or push into array Mongodb Compass NodeJS Express (update is not a function)?

At this moment I try to find the query which works in this case, but then want to update the object. So I want to check if review object exist and if not then create that key name first and then push that object into an array. Else push into that in existing object of array.
Default object looks like (without review object):
const mongoose = require('mongoose');
const musicSchema = mongoose.Schema({
id: {
type: Number,
required: true
},
artist: {
type: String,
required: true
},
title: {
type: String,
required: true
},
release_year: {
type: Number,
required: true
},
genre_id: {
type: Number,
required: true
},
image_url: {
type: String,
required: true
},
reviews: [{
id: {
type: Number,
required: true
},
locale: {
type: String,
required: true
},
rating: {
type: Number,
required: true
},
comment: {
type: String,
required: true
}
}]
});
const Music = mongoose.model("Music", musicSchema); // now we have to create our model
console.log;
module.exports = Music; // export our created model
app.post('/addReview/:id', async (req, res) => {
let idNumber = parseInt(req.params.id); // 501437
let reviewObject = req.body; // {id: "501437", locale: "nl", rating: 3, text: "helello"}
try {
const music = client.db('database').collection('music');
const query = { id: idNumber };
const musicSong = await music.findOne(query);
await musicSong.update({ $push: { reviews: reviewObject } }); // error comes from here
} catch (err) {
console.log(err);
}
});

check if reviews field is not exists then initialise it to blank array
push object to reviews
save() to save main document
app.post('/addReview/:id', async (req, res) => {
let idNumber = parseInt(req.params.id); // 501437
let reviewObject = req.body; // {id: "501437", locale: "nl", rating: 3, text: "helello"}
try {
const music = client.db('database').collection('music');
const query = { id: idNumber };
let musicSong = await music.findOne(query);
if (!Array.isArray(musicSong.reviews)) {
musicSong.reviews = [];
}
musicSong.reviews.push(reviewObject);
music.save();
} catch (err) {
console.log(err);
}
});
Second option using updateOne():
It does not require to find, check and save operations if you use update methods,
app.post('/addReview/:id', async (req, res) => {
const query = { id: parseInt(req.params.id) };
let reviewObject = req.body;
try {
const music = client.db('database').collection('music');
await music.updateOne(query, { $push: { reviews: reviewObject } });
} catch (err) {
console.log(err);
}
});

How can I solve this referencing Problem in mongoose/Node JS

I have route and model for User and then another for Loan. I'm trying to reference the user inside the Loan route but I get this error anytime I test on PostMan:
TypeError: Cannot read property '_id' of undefined
at C:\Users\Micho\Documents\GBENGA\BE\src\routes\loans\index.js:38:47
Loan Model code is:
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
const loanSchema = new Schema({
customerName: {
type: String,
required: true
},
gender: {
type: String
},
address: {
city: String,
state: String,
},
amount: {
type: Number
},
loanTenure: {
type: Number
},
user: {
type: Schema.Types.ObjectId,
ref: 'User'
},
loanStatus: {
type: String,
default: "created"
}
}, {
timestamps: true
})
My route is this:
router.post("/", async (req, res) => {
try {
let loan = await new Loan({...req.body});
loan.save();
await User.findByIdAndUpdate(req.user._id, { $push: { loans: loan._id } })
console.log(req.user)
loan = await Loan.findById(loan._id).populate("user");
res.send(loan);
} catch (error) {
console.log(error)
res.status(500).send(error);
}
});
Kindly help. Thanks

Mongoose assign a collection to another

I am trying to add a post to a user collection after the user was created with empty posts. I have tried with populate with no success .. any help is much appreciated.
// Post Model
const mongoose = require('mongoose');
const { Schema } = mongoose;
const UserModel = require('./user-model');
let PostSchema = new Schema({
author: {
ref: 'users',
type: Schema.Types.ObjectId
},
content: String,
description: String,
date: {
default: new Date(),
type: Date
},
title: String,
updatedAt: {
default: new Date(),
type: Date
}
});
let PostModel = mongoose.model('posts', PostSchema);
module.exports = PostModel;
// User Model
const mongoose = require('mongoose');
const { Schema } = mongoose;
const PostModel = require('./post-model');
let UserSchema = new Schema({
name: {
type: String
},
email: {
lowercase: true,
type: String,
trim: true,
unique: true
},
password: {
type: String,
},
postList: [{
ref: 'posts',
type: Schema.Types.ObjectId
}],
});
const UserModel = mongoose.model('users', UserSchema);
module.exports = UserModel;
// save post controller
exports.savePost = (request, response, next) => {
let { author, description, title } = request.body;
let post = new PostModel({ author, description, title }).save();
UserModel.findById(author)
.then((user) => {
user.postList.push(post);
// Still Fails
// How can i assign the post to the user ?
});
}
Is there any way of doing this other then push or populate ?

To solve this problem I prefer to use $push of mongo
UserModel.findOneAndUpdate({
_id: author.id,
{
$push: {
postList: post
}
}
});

You need to follow this process to save successfully
Save post if success then
Update user to push postId in postlist
can try this one
exports.savePost = (request, response, next) => {
let post = new PostModel(request.body)
post.save(function(err, data) {
if(err) {
//return error
}
// check by console your author is present or not
// let author in your req.body
let author = req.body.author
UserModel.findOneAndUpdate({_id: author},{$push: {postList: post._id}},{new:true} function(error, user) {
if(error) {
// return error
}
console.log(user)
// return success
})
});
}

exports.savePost = (request, response, next) => {
let { user, description, title } = request.body;
let post = new PostModel({ user, description, title });
post.save()
.catch((error) => {
if (error)
throw new Error(error);
})
.then((post) => {
UserModel.findOneAndUpdate({ _id: user }, {$push: { postList: post._id } })
.populate('postList')
.catch((error) => {
if (error)
throw new Error(error);
})
.then((user) => {
user.postList.forEach((item, postion) => {
console.log(`${item} -at ${postion} \n`);
});
});
});
}
This is what i did and it worked after all. I don't know if this is the correct solution but this is working.

mongoose not removing objects

Folks, for some reason this method is not letting me delete a user by email.
I have tested the functions calling this method, and they are in fact being executed.... thoughts?
var deleteUser = function (emailAddress, callback) {
Users.find({ email:emailAddress }).remove( callback );
}
all of code:
var Users = require('./mongo/users').Users;
var deleteUser = function (emailAddress, callback) {
Users.find({ email:emailAddress }).remove( callback );
}
./mongo/users.js:
var mongoose = require('mongoose');
var Schema = require('mongoose').Schema;
var UserSchema = new Schema({
email: {
type: String,
index: true
},
token: {
type: String,
index: true
},
password: String,
uid: {
type: String,
index: true
},
firstName: String,
lastName: String,
roles: Array
});
UserSchema.statics.findByEmail = function (email, callback) {
this.find({
email: new RegExp(email, 'i')
},
callback)
}
var Users = mongoose.model('users', UserSchema);
module.exports = {
Users: Users
}