I know i have to use some but for some reason i cant seem to get it right. i have a collection in my mongodb database of posts. each post has an array of objects named "likes" that references the users that liked this post. so in my backend i want to check if the user exists in the likes array of the post. if it does not exist then like the post, else return with an appropriate message on my react frontend. The code i will include always returns false from some so a user can like a post infinite times.
exports.postLike = async (req, res, next) => {
const postId = req.query.postId;
const userId = req.query.userId;
console.log('postId: ' + postId);
try{
const post = await Post.findById(postId).populate('creator').populate('likes');
const user = await User.findById(userId);
if (!post.likes.some(post => post._id === user._id)){
post.likes.push(user);
console.log('liked a post');
const result = await post.save();
res.status(200).json({ message: 'Post liked!', post: result });
} else {
console.log('Post already liked!');
res.status(200).json({ message: 'Post already liked!', post: post });
}
}catch (err) {
if (!err.statusCode) {
err.statusCode = 500;
}
next(err);
}
};
i clearly haven't understood, yet, how some works so if you can help that would be great. also if you have any other solution that would be good in this case then please post it. i tried some random codes with indexOf and includes for checking but it didn't work either. i am not sure which is the right way to check if the user object is included in the "likes" array of objects. i would prefer not to write any function of my own to check this, i want to do it using an existing function/method provided by javascript.
Going to offer a different route here. You are fetching all the data including a join to the creator and likes just to add a like to the collection. This is a little wasteful and can be achieved by just doing an update and use $addToSet which will add the like if it does not exist.
You then just check nModified in the result to know if it was added or not. So you can have:
const result = await Post.updateOne(
{
id: 1
},
{
$addToSet: {
likes: {
userId: mongoose.Types.ObjectId(req.query.userId)
}
}
}
);
console.info(result.nModified === 1);
Alternatively, you can use some as follows using === to compare type and value:
posts.likes.some(like => like.userId.toString() === req.query.userId)
MongoDB.ObjectId is a wrapper around a primitve, just like Number or Boolean. And just like
new Boolean(true) === new Boolean(true)
will be false, your comparison will fail too. You have to take out the primitive for comparison:
post._id.valueOf() === user._id.valueOf()
Related
In Node JS I have an endpoint where I am trying to get data from two different mongo collections and when trying to piece the data together I am not able to add another property to the JSON object.
const getLessonWithTopics = async (req, res) => {
const lessonId = req.params.id;
// Get the lesson
Lesson.findOne({_id: lessonId}).exec((err, data) => {
let lesson = data;
Topic.find().where('_id').in(data.topics).exec((err, topics) => {
if(err) res.status(500).send("Error something went wrong");
lesson.associatedTopics = topics;
console.log(lesson);
res.json(lesson)
})
})
}
When logging lesson to console it does not have the associatedTopics property even though through searching online I have found multiple instances where some is saying this is how you would add this property. (Ex. Add new attribute (element) to JSON object using JavaScript )
I have tried using var as well, to see if that would change something (maybe make it mutable) it did not.
** When logging the topics object to console it does log the data that I expected so the variable 'topics' is not the issue **
I'm sure that it is something simple that I am missing and hoping someone with a large brain can help figure this out for me.
Any help would be appreciated, Thank you!
Can you try once with the following code?
const getLessonWithTopics = async (req, res) => {
const lessonId = req.params.id;
// Get the lesson
try {
const lession = await Lession.findOne({ _id: lessonId }).lean()
const topics = await Topic.find({ _id: { $in: lession.topics } }).lean()
lession.associatedTopics = topics
res.json(lesson);
} catch (err) {
console.log(err)
res.status(500)
}
After creating a node.js, express, mongoDb REST api for a social media web app with almost all basic social media actions (login, signup, add a post, delete a post, delete account, follow users ...),
I'm currently facing a problem, where after implementing bookmarking a post feature, I'm unable to come up with a solution to remove a bookmarked post from another user's bookmarked posts page, after the first user deletes his account. I'll provide my code below:
(P. S. Bookmarks is an array inside User model. I'd also like to mention the steps that I initially intended for the task:
Get current user by ID
Then get all posts created by this user, which returns an array, so I mapped it to get each Posts id
After that I fetched all users accross the app, and initially intended to compare the posts that live inside bookmarks array inside each user to the posts that the current user have created. Then I'd pull these same posts out of the bookmarks array from each of these users.
--> I think the logic that I've analyzed is maintainable, but it's just not working with me. This is the Code below:
export const deleteUser = async (req, res) => {
try {
let user = await User.findById(req.params.userId)
const userPosts = await Post.find({ creatorId: user._id })
const allUsers = await User.find()
const myPostsIds = userPosts.map((post) => post._id.toString())
//This is the section I've implemented for my task, but obviously
something isn't right
await Promise.all(
myPostsIds.forEach((id) =>
allUsers.map((user) => {
user.bookmarks.includes(id) &&
user.updateOne({ $pull: { bookmarks: id } })
})
)
)
await Post.deleteMany({ creatorId: user._id })
await user.remove()
res.status(200).json({
message: "Account has been deleted successfully!",
})
} catch (err) {
errorHandler(res, err)
}
}
As mentioned in my comments, the value you pass to Promise.all is no array of Promise/array of async functions.
The 2nd error is inside the (currently) forEach function at the .map() you are not returning anything in the map-call.
So this should do it:
// first convert all ids to a promise
await Promise.all(myPostsIds.map(id => new Promise(resolve => {
// during this, await every test and update
return Promise.all(allUsers.map(user => new Promise(resolve => {
// if it includes the id, cast the update and then resolve
if (user.bookmarks.includes(id)) {
// if found, resolve the promise for this user after the change
user.updateOne({ $pull: { bookmarks: id } }).then(resolve)
} else {
// resolve directly if not found.
resolve()
}
// when all users are done for this id, resolve the Promise for the given id
}))).then(resolve)
})))
An easier to read and shorter method would be:
for (const id of myPostIds) {
for (const user of allUsers) {
if (user.bookmarks && user.bookmarks.includes(id)) {
await user.updateOne({ $pull: { bookmarks: id } });
}
}
}
For example I want to update a mongoose document in a put request, I have to do this:
app.put('/update', async(req,res) => {
try{
const product = await Product.findById(req.body.id)
product.name = req.body.name
product.price = req.body.price
procut.discount = req.body.discount
// etc...
await product.save()
res.json(product)
}catch(e){
res.json({message: "Error updating the product"})
}
})
I'm asking if there is another faster and developer friendly way of updating products instead of typing each of the document properties and equal them to the req.body.[property]?
You can try the following for object merging
Object.assign(product, req.body)
note: i haven't tried with mongoose collection
You can use updateMany or findOneAndUpdate model methods, but it is more advisable to use .save()
https://mongoosejs.com/docs/api.html#model_Model.updateMany
https://mongoosejs.com/docs/api.html#model_Model.findOneAndUpdate
If you want to .save() to look cleaner, you can do like this:
async updateEntity(payload) {
const keysToUpdate = Object.keys(payload)
if (keysToUpdate.length === 0) {
throw new Error('Update payload must not be empty!')
}
const entity = await entityModel.findOne({ _id: redirect })
keysToUpdate.forEach((key) => {
entity[key] = payload[key]
})
await entity.save()}
This is the basic structure of the Schema I am working with using mongoose:
const User = {
uid: {
type: String
},
routes: {
type: Array
}
}
In my application there is a POST to /route, in which uid and a new route are provided as "body parameters". In order to add to the routes array, I wrote a code similar to this (the only diference is that I check if the route already exists):
var user = await User.find({uid: uid}) // user is found, as expected
user[0].routes.push(route //parameter)
user.save()
When a POST request is made, though, it throws an error:
TypeError: user.save is not a function
What am I doing wrong?
user in your code is an array of documents
so you'll have mongo documents inside that array
you can't do array.save, you've to do document.save
await user[0].save()
var user = await User.find({uid: uid}) // user is found, as expected
if (user && user.length) {
user[0].routes.push(route //parameter)
await user[0].save(); // save the 1st element of the object
}
if your query returns only 1 record better use https://mongoosejs.com/docs/api.html#model_Model.findOne
var user = await User.findOne({uid: uid}) // user is found, as expected
if (user) {
user.routes.push(route //parameter)
await user.save(); // save the 1st element of the object
}
if you need to find only one specific user you should use findOne function instead
User.findOne({uid: uid})
.then(
(user) => {
user[0].routes.push(route //parameter);
user.save();
},
(err) => {
console.error(err);
}
)
I think bulkSave() can be what you're looking for:
var user = await User.find({uid: uid}
enter code user[0].routes.push(route //parameter)
await User.bulkSave(user)
The problem is probably simple, but my 2 AM brain can't understand what's going on anymore. I'm trying to create a profile page that shows basic public info. The way I'm trying to make it work is pulling out the users username from mongodb when registered the account by his specific _id. If needed, verification I use is JWT.
app.post('/api/user-profile', async (req,res) => {
const { token } = req.body
if(!token) {
return res.json({ status: 'error', error: 'not logged in' })
}
try {
const user = jwt.verify(token, JWT_SECRET)
const userid = user.id
const result = User.findOne({ userid })
console.log(result)
// return res.json({ status: 'ok', name: result })
} catch(error) {
// return res.json({ status: 'error', error: 'something went wrong' })
console.log(error)
}
})
I'm not sure what function should I use, findOne() or findById(). I tried to look at the documentation at mongoose, but the explanation is a bit too hard for me to understand.
P.S User = the user registration model. If needed I can paste in the code.
use findById instead of findOne if userid is _id and use await before the query, so do like this:
const result = await User.findById(userid)
if you want to use findOne :
const result = await User.findOne({"_id" : userid})
if you want a plain object javascript use .toObject after query like this:
const result = await User.findById(userid).toObject()
console.log(result)
I don't have a lot of experience with mongoose but worked with Mongo quite a lot. findOne is a direct correspondent of Mongo's findOne function which receives a query in the format {"key": "expectedValue"}. If you want to use it to get data by id the query is {"_id": user.id}.
Because fetching data by id is a common case, the lib added the method findByID which receives an ID, and then formats the query and makes an internal call to findOne.
For anyone interested, the answer is just like Mohammad Yaser Ahmadi said. Everything works fine, and by getting the username I did:
const user = jwt.verify(token, JWT_SECRET)
const userid = user.id
const result = await User.findById(userid)
const usersName = result.username
console.log(usersName)