Develop Reference

Node Js: Remove string array element from mongoDB

I have a user schema as follows:
const UserSchema = new mongoose.Schema({
skills: [String]
});
module.exports = mongoose.model("User", UserSchema);
And a Fetch request to delete a skill as follows:
const deleteItem = async (id) => {
try {
await fetch(`http://localhost:5000/api/user/deleteskill`, {
method: "DELETE",
headers: { "Content-Type": "application/JSON", token: accessToken },
body: JSON.stringify({ userid: userid , skill:id}),
})
.then((res) => res.json())
.then((data) => {
console.log("USER SKILLS:", data.userskills);
});
} catch (err) {
console.log(err);
}
};
Server
const deleteSkill = async (req, res) => {
try {
const user = await User.findById(req.body.userid)
//user.skills.pull(req.body.skill);
// removeskill = user.skills.filter(function(item) {
// return item !== req.body.skill
// })
if (user.skills.includes(req.body.skill)) {
res.status(400).json("Item Still Exists");
} else {
res.status(200).json("Item Deleted");
}
} catch (error) {
res.status(500).send({ error: error.message });
}
};
the array is in the following structure
[
'skill1', 'java', 'skill5'
]
I have tried to remove the user skill from the array in several ways but I still get res.status(400).json("Item Still Exists");. What I'm doing wrong?

Use the findOneAndUpdate method to find a document with the user id and update it in one atomic operation:
const deleteSkill = async (req, res) => {
try {
let message = "Item Deleted";
let status = 200;
const user = await User.findOneAndUpdate(
{ _id: req.body.userid },
{ $pull: { skills: req.body.skill } },
{ new: true }
)
if (user && user.skills.includes(req.body.skill)) {
message = "Item Still Exists";
status = 400;
} else if (!user) {
message = "User Not Found";
status = 404;
}
res.status(status).send({ message });
} catch (error) {
res.status(500).send({ error: error.message });
}
};

I believe you want to remove skills from the database then the following function could help you out.
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/";
MongoClient.connect(url, function(err, db) {
if (err) throw err;
var dbo = db.db("mydb");
var myquery = { userid: userid, skillid: skillid};
dbo.collection("skills").deleteOne(myquery, function(err, obj) {
if (err) throw err;
console.log("1 document deleted");
db.close();
});
});

You have a method of removing elements from arrays, if you want to remove the first one you could use array.shift (more on it here), but if you want to delete it completely from your database you could always, find it and then update it.

User.update({ _id: userid }, { $pull: { "skills": "[skill]" }})

How to filter data from mongo collection subarray with subarray data of other collection

Baiscally making a node.js, mongodb add friends functionality where having the option of list user to add in friends list, sent friends request, accept friends request, delete friends request, block friends request.
Register Collection
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
let Register = new Schema(
First_Name:{
type: String,
required: true
},
Last_Name: {
type: String
},
Email: {
type: String,
unique: true,
lowercase: true,
required: true
},
Friends:[{type: String}],
});
module.exports = mongoose.model('Register', Register);
Friends Collection
const mongoose = require('mongoose');
const Schema = mongoose.Schema;
var ObjectId = require('mongodb').ObjectID;
let Friends = new Schema({
Requester: {
type: ObjectId,
required: true
},
Recipients: [{Recipient:{type:ObjectId},Status:{type:Number}}],
});
module.exports = mongoose.model('Friends', Friends);
Inside Node.js Post API
var Register = require('../models/register.model');
var Friends =require('../models/friends.model');
router.post('/getdata',function(req,res)
{
let Email="example#example.com";
Register.findOne({ Email : Emails }, function(err, user) {
Friends.findOne({ Requester :user._id }, function(err, user1) {
Register.find({$and:[{Friends:{$nin:[user._id]}},{_id:{$ne:user1.Recipients.Recipient}}]},function(err, user2) {
console.log("user2",user2);
//Here User2 data is not coming
//How to get data so can able to list user that is not added yet in FriendList
//Mainly user1.Recipients.Recipient this is not working because //Recipients is array so how can match all data with array, if i am //using loop then find return data scope ends on inside find closing //braces only.
//Any suggestion
});
});
});

So if I have it correct, you want to do the following:
Find a registration based on a given email
Find the friends related to this user
Find registrations that are not yet in the friend list of the user
Also, given what you've typed, I'm assuming A can be the friend of B, but that doesn't mean B is the friend of A.
While the data structure you currently have may not be optimal for this, I'll show you the proper queries for this:
var Register = require('../models/register.model');
var Friends =require('../models/friends.model');
router.post('/getdata',function(req,res) {
const email = "example#example.com";
Register.findOne({ Email: email }, function(err, user) {
if (err) {
console.error(err);
return;
}
Friends.findOne({ Requester: user._id }, function(err, friend) {
if (err) {
console.error(err);
return;
}
const reciptientIds = friend.Recipients.map(function (recipient) {
return recipient.Recipient.toString();
});
Register.find({Friends: { $ne: user._id }, {_id: { $nin: recipientIds }}, function(err, notFriendedUsers) {
if (err) {
console.error(err);
return;
}
console.log(notFriendedUsers);
});
});
});
});
P.S. This "callback hell" can be easily reduced using promises or await/defer

Finally able to solve it, below is the solution
var Register = require('../models/register.model');
var Friends =require('../models/friends.model');
router.post('/getdata',function(req,res)
{
let Emails="example#example.com";
Register.findOne({$and:[{ Email : Emails}] }, function(err, user) {
if (err) {
console.error(err);
return;
}
Friends
.findOne({ Requester: user._id },
{ _id: 0} )
.sort({ Recipients: 1 })
.select( 'Recipients' )
.exec(function(err, docs){
docs = docs.Recipients.map(function(doc) {
return doc.Recipient; });
if(err){
res.json(err)
} else {
console.log(docs,"docs");
Register.find({$and:[{Friends: { $ne: user._id }},{_id: { $nin: docs }},{_id:{$ne:user._id}}]}, function(err, notFriendedUsers) {
if (err) {
console.error(err);
return;
}
console.log(notFriendedUsers);
});
}
})
});

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

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);
})

Why do I get an error upon entering user into a database?

I'm teaching myself Mongodb. At first, I ran npm install --save mongoose uuid in Terminal to start things off. The goal of my program is to store a user in the database.
In Terminal, after running node index.js I want it to say:
About to save!
Saved!
But what I'm seeing in Terminal is (below):
Here's index.js
var mongoose = require('mongoose');
var uuid = require('uuid');
var Schema = mongoose.Schema;
/* New code from suggested website in error */
var promise = mongoose.connect('mongodb://localhost:testMongo/testMongo', {
useMongoClient: true,
});
promise.then(function(db) {
db.model();
connection.openUri('mongodb://localhost:testMongo/testMongo', { /* options */ });
var userSchema = new Schema({
email: {
type: String,
unique: true
},
password: {type: String},
todos: [
{
text: {type: String}
}
]
});
userSchema.pre('save', function(next) {
console.log("About to save!");
var user = this;
user.password = uuid.v4();
next();
});
var User = mongoose.model('user', userSchema);
var email = 'test#test.com';
// var user = new User({
// email: email
// });
//
// user.save(function(err) {
// if(err) {
// return console.log(err);
// } else {
// return console.log("User was saved!");
// }
// })
//
// console.log("Outside of callback!");
var text = "This is a todo.";
User.findOne({email: email}, function(user, err) {
if(err) {
return console.log(err);
}
if(!user) {
return console.log("Couldn't find user!");
}
var count = user.todos.push({
text: text
});
console.log(count);
user.save(function(err){
if(err) {
console.log(err);
} else {
console.log("Saved!");
}
});
});
Error in Terminal:
(node:14312) DeprecationWarning: `open()` is deprecated in mongoose >= 4.11.0, use `openUri()` instead, or set the `useMongoClient` option if using `connect()` or `createConnection()`. See http://mongoosejs.com/docs/connections.html#use-mongo-client
{ _id: 595fe7c14a9810330c75aacc,
password: '297d5907-d9d7-49ef-800c-97a56aa395f7',
email: 'test#test.com',
__v: 0,
todos: [] }

That is not an error. It clearly says it's a warning: DeprecationWarning.
Also the message gives you a link to resolve the warning: http://mongoosejs.com/docs/connections.html#use-mongo-client