MongoDB Cannot read property 'push' of undefined - javascript

I'm new to node.js, express and MongoDB, and still learning. The program had a runtime error when I tried some data association in MongoDB models. The reference has been included in the model already but push() method can't recognize it. The models look like this:
var mongoose = require('mongoose');
var commentSchema = new mongoose.Schema({
text: String,
author: String
});
var Comment = mongoose.model("comments", commentSchema);
module.exports = Comment;
and
var mongoose = require('mongoose');
var campgroundSchema = new mongoose.Schema({
name: String,
image: String,
description: String,
comments: [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Comment"
}
]
});
var Campground = mongoose.model("campgrounds", campgroundSchema);
module.exports = Campground;
The part where these two models are needed looks like this:
Campground.remove({}, function(err){
if(err){
console.log(err);
}else{
console.log("removed campground!");
data.forEach(function (seed) {
Campground.create(seed, function (err, data) {
if(err){
console.log(err);
} else{
console.log("camp created");
Comment.create(
{
text: "nice campsite!",
author: "haiderboi"
},function (err, comment) {
if(err){
console.log(err);
}else{
Campground.comments.push(comment);
Campground.save();
console.log("comment added");
}
}
);
}
});
});
}
});
It seems like the array is already defined in the Campground model so I can't tell the error. Thanks in advance!

Hey i was have problem like this in my project.And it wasn't working because my blogpost schema was like this:
var campgroundSchema = new mongoose.Schema({
name: String,
image: String,
description: String,
comments: [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Comment"
}
]});
And changed it to this:
var campgroundSchema = new mongoose.Schema({
name: String,
image: String,
description: String,
comments: [
{
type: mongoose.Schema.Types.Mixed,
}
]});
Because up there you're referring ObjectId and you're setting an object inside your code.It's not match.So you should try like this

Found the problem!
Instead of doing
Campground.comments.push(comment);
I should do
data.comments.push(comment);
since I wanna push the comment to the current Campground object, I should use the object returned by the callback.

Related

Issue with adding comment

I am making a node API. I am stuck at adding a comment to a story.
I am able to create a comment but instead of pushing it to a given story, it was trying to create a new instance of story.
Story.findOne(req.params.id, (err, foundstory) => {
if(err){
res.status(500).json({msg:err})
}else{
let comment = new Comment()
comment.body = req.body.body
comment.author = req.body.author
console.log(foundstory)
//save comment//
comment.save((err, comment) => {
if(err){
res.status(500).json({msg:err})
}else{
//pushing comment to comments array (ref) in story
foundstory.comments.push(comment)
foundstory.save()
res.status(200).json({msg:"Comment saved"})
}
})
}
})
Story Schema
import mongoose from 'mongoose'
import User from './user'
import Comment from './comment'
const Schema = mongoose.Schema
const ObjectID = mongoose.Schema.Types.ObjectId
const storySchema = new Schema({
//subdoc ref from user
author: {type: ObjectID, ref: 'User'},
//subdoc ref from comment
comments: [{
type: ObjectID,
ref: 'Comment'
}],
//contents of story//
title: {type: String, required: true},
body: {type: String, required: true},
date: {type: Date, default: Date.now()},
tags: [{type: String}]
})
module.exports = mongoose.model('Story', storySchema)
Comment Schema
import mongoose from 'mongoose'
import User from './user'
const Schema = mongoose.Schema
const ObjectID = mongoose.Schema.Types.ObjectId
const commentSchema = new Schema({
body : {type: String, required: true},
author: {type: ObjectID, ref: 'User'}
})
module.exports = mongoose.model('Comment', commentSchema)
I have an array of type "Comment" in my "Story" schema. My attempt is to push those comment to that array.
try changing your code like this:
Story.findById(req.params.id, (err, foundstory) => {
if (err) res.status(500).json({
msg: err
});
else if (!foundStory) res.status(400).json({
msg: "Story Not Found"
});
else {
let comment = new Comment();
comment.body = req.body.body;
comment.author = req.body.author;
//save comment//
comment.save(async (err, comment) => {
if (err) res.status(500).json({
msg: err
});
else {
foundstory.comments.push(comment._id);
await foundstory.save();
res.status(200).json({
msg: "Comment saved"
})
}
})
}
})
I've changed the findOne() method with findById(), also the 'foundstory.save()' method is an asynchronous call, so i used async\await to handle it.
Hope this helps :)

Unable to save to an asssociate array in mongodb using mongoose

var mongoose = require("mongoose"),
campground = require("./models/campground"),
comment = require("./models/comment");
var data = [{
name: "Offside Lake",
image: "https://images.unsplash.com/photo-1504280390367-361c6d9f38f4?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",
description: "Whatever evrr"
},
{
name: "Reality Check",
image: "https://images.unsplash.com/photo-1517824806704-9040b037703b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",
description: "wabdiwyu"
},
{
name: "Wawu Land",
image: "https://images.unsplash.com/photo-1508873696983-2dfd5898f08b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",
description: "Just be feeling Wawu"
}
];
var text = {
text: "Hullabaloo",
author: "Olalaa"
};
campground.comments = new Array();
function seedDB() {
campground.deleteMany({}, function(err) {
if (err) {
console.log(err);
} else {
console.log("removed");
data.forEach(function(camp) {
campground.create(camp, function(err, camp) {
if (err) {
console.log(err);
} else {
console.log("Successfully added");
comment.create(text, function(err, comment) {
if (err) {
console.log(err);
} else {
campground.comments.push(comment);
campground.save();
console.log("comment added");
}
});
}
});
});
}
});
}
I have two mongoose models campground and comment. Inside the campground schema, I have the comments associative array in the campground schema. I am trying to add comments to my comments array but I am getting the error - campground.save is not a function. Even tried campground.markModified("comment") then campground.save(), getting the same error
//my campground schema
var mongoose = require("mongoose");
var campSchema = new mongoose.Schema({
name: String,
image: String,
description: String,
comments: [{
type: mongoose.Schema.Types.ObjectId,
ref: "comment"
}]
});
module.exports = mongoose.model("Camp", campSchema);
//my comment schema
var mongoose = require("mongoose");
var commentSchema = mongoose.Schema({
text: String,
author: String
})
module.exports = mongoose.model("comment", commentSchema);
If I understand what you are trying to do, you are trying to create a campground and place the comments inside.
If that is so, then the code may look something like this (placed everything in one file):
const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/test', {useNewUrlParser: true});
var data = [
{
name: "Offside Lake",
image: "https://images.unsplash.com/photo-1504280390367-361c6d9f38f4?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",
description: "Whatever evrr"
}, {
name: "Reality Check",
image: "https://images.unsplash.com/photo-1517824806704-9040b037703b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",
description: "wabdiwyu"
}, {
name: "Wawu Land",
image: "https://images.unsplash.com/photo-1508873696983-2dfd5898f08b?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=500&q=60",
description: "Just be feeling Wawu"
}
];
const comment = mongoose.model('comment', new mongoose.Schema({
text: String,
author: String
}));
const campground = mongoose.model('Camp', new mongoose.Schema({
name: String,
image: String,
description: String,
comments: [{
type: mongoose.Schema.Types.ObjectId,
ref: "comment"
}]
}));
var text = {
text: "Hullabaloo",
author: "Olalaa"
};
campground.deleteMany({}, function(error) {
if (error) {
console.error(error);
return;
}
console.log("Removed");
data.forEach(function(camp) {
campground.create(camp, function(error, newCamp) {
if (error) {
console.error(error);
return;
}
console.log("Successfully added");
comment.create(text, function(err, newComment) {
if (err) {
console.error(err);
return;
}
newCamp.comments.push(newComment);
newCamp.save();
console.log("Comment added");
})
});
})
})
The problem was due to the fact that you kept the same name throughout and that might have confused you a bit.
What you wanted to do was camp.comments.push(comment) camp.save() instead of campground.comments.push(comment) and campground.save() respectively.
As a friendly advice:
Switch to using promises instead of callbacks, you may set yourself up for what is known as Callback hell
As much as possible try not to rely on the closure nature of JavaScript and keep naming your variables the same throughout. That leads to problems like what you are experiencing now

Add array to subdocument Mongoose

I am trying to add an array to an existing subdocument in Mongoose using Express, but I can't seem to figure it out
This is my Mongoose model:
var subitems = new mongoose.Schema({
_id: ObjectId,
title: String,
messages: Array
});
var menuItems = new mongoose.Schema({
title : String,
subitem: [subitems]
}, {collection: 'menu_items'});
module.exports = mongoose.model("menu_items", menuItems);
I am using the ID from the subdocument to update the specific item in "subitem"
This is the Express Update:
postController.postArticles = function(req, res,item) {
var id = req.body.id;
var saveData = {
title: req.body.title,
text: req.body.text
};
item.update({_id: id}, {$push:{messages: saveData}},(err, result) => {
});
};
It is not adding anything to the db, anyone have an idea?
With mongoose you have to update the whole object. So, first you get item with find or findOne, and the you have to add the element to the array with push, and finally you call .save() method of the mongoose object.
Something like this:
postController.postArticles = function(req, res,item) {
var id = req.body.id;
item.findOne({_id: id}, function(error, myItem) {
var saveData = {
title: req.body.title,
text: req.body.text
};
myItem.messages.push(saveData);
myItem.save();
});
};

Mongoose + Mongodb User.update not working

What I am trying to do is create a new collection, and push that collection into a specific User.collections array. I have read many stackoverflow posts and they all say to use either User.update() or User.findOneAndUpdate(). I am have no luck with either. I can create a Collection and that is saved to mongo so I know I am indeed accessing the db. Here is my code, if any of you can help I would appreciate it.
User Schema
const mongoose = require('mongoose');
const { Schema } = mongoose;
const userSchema = new Schema({
googleID: String,
givenName: String,
familyName: String,
collections: [
{
type: mongoose.Schema.Types.ObjectId,
ref: "collection"
}
]
});
mongoose.model('users', userSchema);
Collection Schema:
const mongoose = require('mongoose');
const { Schema } = mongoose;
const collectionSchema = new Schema({
type: String,
name: String,
gamesCollected: [
{
id: Number
}
]
});
mongoose.model('collection', collectionSchema);
And my route:
router.get('/get_collection', (req, res) => {
const collection = new Collection({
type: 'SNES',
name: 'First SNES Collection',
gamesCollected: [{ id: 5353 }]
}).save();
User.update({googleID: req.user.googleID}, {$push: {collections: collection}});
});
Save is not a synchronous operation but asynchronous so you need to use the promise it returns and handle it and once it is complete then update the user model. Something among these lines:
router.get('/get_collection', async (req, res) => {
let collection = new Collection({
type: 'SNES',
name: 'First SNES Collection',
gamesCollected: [{ id: 5353 }]
})
await collection.save().exec();
await User.update(
{googleID: req.user.googleID},
{$push: {collections: collection._id}}
).exec();
});

unhandled promise rejection warning - couldn't store into database

Data comming from req is store in Comment collection but it is not store in Product collection and i'll get an error message
app.post("/products/:id/comments", function(req, res) {
//lookup campground using ID
Product.findById(req.params.id, function(err, product) {
if (err) {
console.log(err);
res.redirect("/products");
} else {
Comment.create(req.body.comment, function(err, comment) {
if (err) {
console.log(err);
} else {
console.log("aaaaaa");
product.comments.push(comment);
console.log("bbbbbb");
product.save();
console.log("cccccc");
res.redirect('/products/' + product._id);
}
});
}
});});
and following is Product
var mongoose = require("mongoose"),
productSchema = new mongoose.Schema({
name: String,
img: String,
price: Number,
desc: String,
comments: [{
type: mongoose.Schema.Types.ObjectId,
ref: "Comment"
}],
created: {
type: Date,
default: Date.now()
}});module.exports = mongoose.model("Product", productSchema);
and this is Comment Schema
var mongoose = require("mongoose"),
commentSchema = mongoose.Schema({
text: String,
author: String
});module.exports = mongoose.model("Comment", commentSchema);
and i got following output :-
enter image description here
so it's store in commentSchema but it's not store in product.comments and when i run site that also redirect to products/:id, what i'm missing to store comment into database ??
If you don’t pass a callback function to save() then it will return a promise.
Therefore, you are getting the error as you have not added a catch.
Try passing a callback to save():
// ...
product.save(function(err, result) {
if (err) {
// Handle error
}
console.log("cccccc");
res.redirect('/products/' + product._id);
})

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