I have a function on my server that is supposed to get a post by its ID. The function works up until the "foundPost" constant, where I can't seem to find one of the documents from the "posts" array. I've tried substituting findOne for find and the ObjectIds work for the const 'post'.
I've double checked that post_id is 62067c1211eea1531d5872f4
Here is the function to find a post:
const postById = async (req, res) => {
const userId = req.params.userId;
const post_id = req.params.post_id;
const posts = await Post.findOne({ user: userId });
console.log(posts); //see this below
const foundPost = await posts.findOne({ "upload": post_id }); //error here
console.log(foundPost);
return res.json({ success: true, Post: foundPost });
};
Here is what 'console.log(posts)' returns:
[
{
upload: new ObjectId("623b681bdf85df9086417723"),
edited: false,
title: 'Test 1',
description: 'testing post 1',
name: 'John ',
sharedPost: 0,
},
{
upload: new ObjectId("62067c1211eea1531d5872f4"),
edited: false,
title: 'Test 2',
description: 'testing post 2',
name: 'John ',
sharedPost: 0,
}
]
I'm hoping that the function will return:
{
success: true,
{
upload: new ObjectId("62067c1211eea1531d5872f4"),
edited: false,
title: 'Test 2',
description: 'testing post 2',
name: 'John ',
sharedPost: 0,
},
}
Can anyone see why the line const foundPost = await posts.findOne({ "upload": post_id }); isn't working?
Thank you for your help.
****** Response to answer ******
Hello, thanks a lot for your answer, unfortunately it's still giving an error. Please see below the model for the code I'm using:
const PostSchema = new Schema({
user: {
type: Schema.Types.ObjectId,
ref: "user",
},
post: [
{
user: {
type: Schema.Types.ObjectId,
ref: "user",
},
upload: {
type: Schema.Types.ObjectId,
ref: "upload",
},
title: {
type: String,
},
description: {
type: String,
},
},
],
date: {
type: Date,
default: Date.now,
},
});
I noticed that you used 'userProfile.posts' which I adapted to 'userProfile.post' to match this schema. I'm also not sure if you wanted to use 'subdoc' or 'subDoc' in line 11 of your code, but I tried both with the same error for each. I determined that the code stuck at the const subDocs = userPosts.filter(filter); line. I've looked into the .filter method you've used and can't find any potential errors. Not sure what the issue is.
Thanks
The issue is that you cannot run another mongo query on objects that were result of a previous query.
//will return a single document if found, or null if not found.
const posts = await Post.findOne({ user: userId });
//this will not work because at this point 'posts' will be either a Document or null value
//So the object will not have the method 'findOne' available.
const foundPost = await posts.findOne({ "upload": post_id });
The solution is to deal correctly with the types of objects you have.
Below is a functional and safe implementation that solves your issue:
const userPosts = await Post.findOne({ user: userId }).exec();
if (!userPosts) {
// document not found with provided userId
return res.json({ success: false });
}
//here we have a Document
//check if document has 'posts' property and is an array
if (userPosts.posts) {
//filter the posts array
const filter = function(subDoc) {
return subdoc.upload === post_id
}
const subDocs = userPosts.filter(filter);
//filter returns an array, so we must check if has itens
//then we grab the first item
if (subDocs.length > 0) {
const foundPost = subDocs[0];
return res.json({ success: true, Post: foundPost });
}
//subDoc not found, return correct response
return res.json({ success: false });
}
If your Post model schema is what I'm supposing to be, this code will work perfectly.
const schema = mongoose.schema({
user: Number,
posts: [{ upload: Number }]
})
In case of error, please add the code of the model schema structure.