Mongoose select specific fields from array

Question

I'm trying to reduce my API data size to remove unwanted data. I have schema like this

const course = mongoose.Schema(
  {
    course_name: { type: String, require: true },
    disabled: { type: String, required: true, default: false },
    subject_ids: [
      {
        type: mongoose.Schema.ObjectId,
        ref: 'subject',
        require: true,
      },
    ],
  },
  { timestamps: true }
);

after applying the find query i have data like this

 {
        "disabled": "false",
        "subject_ids": [
            {
                "disabled": "false",
                "_id": "60b0bdd5cd7bd635ecf07cd5",
                "subject_name": "CSS",
                "createdAt": "2021-05-28T09:54:29.147Z",
                "updatedAt": "2021-05-28T09:54:29.147Z",
                "__v": 0
            },
            {
                "disabled": "false",
                "_id": "60b0bdd5cd7bd635ecf07cd7",
                "subject_name": "Jquery",
                "createdAt": "2021-05-28T09:54:29.147Z",
                "updatedAt": "2021-05-28T09:54:29.147Z",
                "__v": 0
            }
        ],
        "_id": "60b0e3f3012b2b272432e9f9",
        "course_name": "Data Science",
        "createdAt": "2021-05-28T12:37:07.103Z"
    }

API I have tried something like this. I already remove data from the outside array, but I don't know how I can remove it from the inside. I do lots of google search but I didn't get

router.get('/get-course/:status', async (req, res) => {
  try {
    const data = await COURSE.find({})
      .populate('subject_ids')
      .select({ updatedAt: 0, __v: 0 })
      .exec();

    res.json(data);
  } catch (error) {
    res.status(404).json({ err: 1, message: error.message, error });
  }
});

I want data should be like this

 {
        "disabled": "false",
        "subject_ids": [
            {
             
                "_id": "60b0bdd5cd7bd635ecf07cd5",
                "subject_name": "CSS",
               
            },
            {
               
                "_id": "60b0bdd5cd7bd635ecf07cd7",
                "subject_name": "Jquery",
              
            }
        ],
        "_id": "60b0e3f3012b2b272432e9f9",
        "course_name": "Data Science",
        "createdAt": "2021-05-28T12:37:07.103Z"
    }

How to get specific data from array

Does this answer your question? [Populating only specific fields in mongoose](https://stackoverflow.com/questions/53589758/populating-only-specific-fields-in-mongoose) — turivishal, May 28 '21 at 13:11
i'm getting error :-Invalid select: select only takes 1 argument — Mohd Sabban, May 28 '21 at 13:23
i think you used second argument in select, you need to add second argument in populate, check again that question. — turivishal, May 28 '21 at 13:25

score 1 · Answer 1 · answered Mar 29 '22 at 11:39

U can use

router.get('/get-course/:status', async (req, res) => {
  try {
    const data = await COURSE.find({})
      .select("-subject_ids.disabled -subject_ids.createdAt -subject_ids.updatedAt -subject_ids.__v")
      .exec()

    res.json(data);
  } catch (error) {
    res.status(404).json({ err: 1, message: error.message, error });
  }
});

The

 .select("-parentArray.child")

excludes the child property of all elements in the Array.

score 0 · Answer 2 · answered May 28 '21 at 13:10

Try this

router.get('/get-course/:status', async (req, res) => {
  try {
    const data = await COURSE.find({})
      .populate('subject_ids')
      .select({ 
        updatedAt: 0, 
        __v: 0,
        subject_ids.disabled: 0,
        subject_ids.createdAt: 0
        subject_ids.updatedAt: 0
        subject_ids.__v: 0
      })
      .exec();
    res.json(data);
  } catch (error) {
    res.status(404).json({ err: 1, message: error.message, error });
  }
});

I already tried this also like .select({ updatedAt: 0, __v: 0, 'subject_ids.disabled': 0 }) — Mohd Sabban, May 28 '21 at 13:15

score 0 · Answer 3 · answered May 28 '21 at 13:40

0

Try this:

populate('subject_ids','subject_name').exec()

answered May 28 '21 at 13:40

Ravi Gajera

169
6

Mongoose select specific fields from array

3 Answers3