Mongoose: push a string into array - node.js

Question

I have a website where any logged-in user can leave a review for the shop.
So basically I have two schemas:
const journalSchema = new mongoose.Schema({
title: String,
category: String,
subcategory: String,
rating: Number,
review: [{type: String}],
link: String,
description: String,
});
const userSchema = new mongoose.Schema ({
username: String,
password: String,
journal: [{type: mongoose.Schema.Types.ObjectId, ref: 'Journal'}]
});
const Journal = mongoose.model("Journal", journalSchema);
const User = mongoose.model("User", userSchema);
form from the ejs file:
<div class="container my-3">
<h1>Compose</h1>
<form class="" action="/stats" method="post">
<div class="form-group">
<label for="review">Description</label>
<textarea id="review" class="form-control" name="journalReview" rows="5" cols="30"></textarea>
</div>
<button class="btn btn-primary my-2" type="submit" name="button">Publish</button>
</form>
</div>
post route:
app.post("/stats", function(req, res){
if(req.isAuthenticated()){
const favJournal = req.body.savedJournal;
const userId = req.user.id;
const userReview = req.body.journalReview;
User.findById(userId, function(err, foundUser){
Journal.findById(favJournal, function(err, foundJournal){
if(err){
console.log(err);
}
else{
if(foundUser){
foundJournal.review.push(userReview);
foundJournal.save(function(){
console.log(foundJournal);
});
foundUser.journal.addToSet(foundJournal);
foundUser.save(function(){
res.redirect("/favourite");
});
}
}
});
})
.populate('journal')
.exec(function(err, user){
if(err) return handleError(err);
});
}
else{
res.redirect("/login");
}
});
Every time I try to push review from the ejs file I keep getting this error:
events.js:353
throw er; // Unhandled 'error' event
^
TypeError: Cannot read property 'review' of null
at C:\Users\HelloThere\Desktop\miesto\app.js:337:24
at C:\Users\HelloThere\Desktop\miesto\node_modules\mongoose\lib\model.js:5065:18
at processTicksAndRejections (internal/process/task_queues.js:77:11)
Emitted 'error' event on Function instance at:
at C:\Users\HelloThere\Desktop\miesto\node_modules\mongoose\lib\model.js:5067:15
at processTicksAndRejections (internal/process/task_queues.js:77:11)
I tried different solutions from similar posts. Like mongoose methods: findOneAndUpdate and updateOne, but they just return null.

Answer 1

Instead of getting the shop and manipulating it with JavaScript code and then saving it back to the database, you could achieve this through findOneAnUpdate and $push operator.
For instance, this query
Shop.findById( shopId, (shop) => {
shop.products.push(product);
shop.save();
}
can be done through this query
Shop.findOneAndUpdate(
{ _id: shopId },
{ $push: {
products: product
}
})
$pop, $push, and $pull are very powerful tools to manipulate arrays in Mongoose. Take a look at the docs.
For the error you're getting, I think you're getting because you're passing a wrong journalId to findById. Check with MongoDB Compass if you do have a document with that id favJournal

Answer 2

I think I figured out the cause of the problem, I have two post forms in my ejs file, and since both forms have submit button with nothing differentiating them, only the first form gets called in the post route.