Sort Child Array Object of mongodb Document

Question

I am trying to sort a collection with React and MongoDB to have the newest comments on top. I have a database model Employee and inside an array of comment objects like so comments[commentsSchema].

I'd like to get those comments sorted.

This is my model :

import mongoose from 'mongoose';

const commentsSchema = new mongoose.Schema(
    {
        userName: { type: String, required: true },
        comment: { type: String, required: true },
    },
    {
        timestamps: true,
    }
);

const employeeSchema = new mongoose.Schema(
    {
        userName: { type: String, required: true },
        email: { type: String, required: true, unique: true },
        firstName: { type: String, required: true },
        lastName: { type: String, required: true },
        address: { type: String, required: true },
        slug: { type: String, required: true, unique: true },
        role: { type: String, required: true },
        comments: [commentsSchema],
    },
    {
        timestamps: true,
    }
);

const Employee = mongoose.model('Employee', employeeSchema);
export default Employee;

and this is my router:

userRouter.get('/slug/:slug', isAuth, async (req, res) => {
    const employee = await Employee.findOne({ slug:
        req.params.slug,
    });

    if (employee) {
        res.send(employee);
    } else {
        res.status(404).send({ message: 'Employee Not Found' });
    }
});

Employee Collection, Comments Array inside, Comment Objects inside Array. Each Object in Array is each Comment:

id: ObjcetId(6367fd80c6c9b16f4e7dd9cc)
userName: testName
email: testEmail
adress: testAddress
comments: Array
  0: Object
  1: Object
  2: Object   
createdAt: 2022-11... 

      0: Object
         userName: 
         comment:
         _id:
         createdAt:
    
      1: Object
         userName: 
         comment:
         _id:
         createdAt:

      2: Object
         userName: 
         comment:
         _id:
         createdAt:

     
 So I am trying to show Object 2 as Firts, because it is the 
 newest Comment

You should write code with right coding style so that other users can check your code clearly. — Gabriel Aoki, Nov 03 '22 at 20:09
I mean when you post question, you should use code block '{ }' (you can find this on stackoverflow post editor) for your code part. — Gabriel Aoki, Nov 03 '22 at 20:18
I know but it does not allow me to post a question when I click on code block. so i manually changed it so that its readable now. — Davit Shavliashvili, Nov 03 '22 at 20:24
Dublicated with https://stackoverflow.com/questions/9349282/how-to-sort-array-of-embedded-documents-via-mongoose-query — Fırat Taşkın, Nov 04 '22 at 10:49

Nir Levy · Answer 1 · 2022-11-07T14:10:00.080

0

The simplest way to do this is to sort the comments after retrieving the data.

userRouter.get('/slug/:slug', isAuth, async (req, res) => {
    const employee = await Employee.findOne({ slug:
        req.params.slug,
    });

    // Sort comments by createdAt
    employee.comments.sort((a,b) => b.createdAt - a.createdAt);

    if (employee) {
        res.send(employee);
    } else {
        res.status(404).send({ message: 'Employee Not Found' });
    }
});

edited Nov 07 '22 at 14:10

answered Nov 05 '22 at 09:00

Nir Levy

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Hi Levy, sadly it does not work for me. – Davit Shavliashvili Nov 05 '22 at 09:31
Try `employee.comments.sort((a,b) => a.toObject().createdAt - b.toObject().createdAt);` and let me know if it works. – Nir Levy Nov 06 '22 at 13:38
Hi Levy, thansk for the response, but it still does not work =) – Davit Shavliashvili Nov 06 '22 at 18:56
I am sorry @DavitShavliashvili, I suggest you take a look at the data in the collection and make sure your comments really have the timestamps you are looking for. I am not sure the `timestamps` trick will work with sub-schemas. Also, it would be helpful if you could post the code that inserts the data. – Nir Levy Nov 07 '22 at 08:04
check out I added mongoDB Strukture of Document. thanks – Davit Shavliashvili Nov 07 '22 at 10:51
@davit I've changed the sort order based on your clarification since it is now clear you need reverse sort. – Nir Levy Nov 07 '22 at 14:10
I just changed sort to revers and thats it. thanks man now its working as axpected.. – Davit Shavliashvili Nov 07 '22 at 15:55
@DavitShavliashvili if you found my answer helpful it would be kind of you if you could accept the answer – Nir Levy Nov 08 '22 at 17:39

Sort Child Array Object of mongodb Document

1 Answers1