Problem in Nested Arrays in Mongoose and NodeJS

Question

I have this complex category schema which contains an array of subcategories and each subcategory has an array of books..

Could someone help me make a proper POST request for this category schema where I want the request body to look like that schema to contain a category nested in it an array of subcategories nested in each subcategory an array of books with Mongoose and NodeJS. This is the schema :-

{
    "categoryName": "engineering",
    "subcategories": [
        {
            "subcategoryName": "chemical enginnering",
            "books": [
                {
                    "bookName": "",
                    "author": "",
                    "ratings": [3, 4, 5, 3],
                    "feedbcks": ["awesome book", "very amazing book"],
                    "price": 222
                }
            ]
        },
        {
            "subcategoryName": "mechanical engineering",
            "books": [
                {
                    "bookName": "",
                    "author": "",
                    "ratings": [3, 4, 5, 3],
                    "feedbcks": ["awesome book", "very amazing book"],
                    "price": 222
                }
            ]
        }
    ]
}

I tried this code but doesn't make it

const category = new Category({
    categoryName: req.body.categoryName,
    subcategories: [
      new SubCategory({
        subCategoryName: req.body.subCategoryName,
        books: [
          new Book({
            bookName: req.body.bookName,
            price: req.body.price,
            ratings: req.body.ratings,
            feedbacks: req.body.feedbacks,
            author: req.body.author
          })
        ]
      })
    ]
  });

  try {
    const savedCategory = await category.save();
    res.send(savedCategory);
  } catch (error) {
    res.send(error.message);
  }

Jakub A Suplicki · Accepted Answer · 2020-08-08 02:04:35Z

1

I believe that your schema could look like this (subdocuments):

const Category = new Schema({
    categoryName: String,
    subcategories: [{
        subcategoryName: String,
        books: [{
            bookName: String,
            author: String,
            ratings: Array,
            feedbacks: Array,
            price: Number
        }]
    }]
})

or

const Book = new Schema({
    bookName: String,
    author: String,
    ratings: Array,
    feedbacks: Array,
    price: Number
})

const Subcategory = new Schema({
    subcategoryName: String,
    books: [Book]  
})

const Category = new Schema({
    categoryName: String,
    subcategories: [Subcategory]
})

To save it, I think you could just pass the entire data object into your Model:

const category = {
    "categoryName": "engineering",
    "subcategories": [
        {
            "subcategoryName": "chemical enginnering",
            "books": [
                {
                    "bookName": "",
                    "author": "",
                    "ratings": [3, 4, 5, 3],
                    "feedbacks": ["awesome book", "very amazing book"],
                    "price": 222
                }
            ]
        },
        {
            "subcategoryName": "mechanical engineering",
            "books": [
                {
                    "bookName": "",
                    "author": "",
                    "ratings": [3, 4, 5, 3],
                    "feedbacks": ["awesome book", "very amazing book"],
                    "price": 222
                }
            ]
        }
    ]
}


const newCategory = new Category(category);
try {
    const savedCategory = await newCategory.save();
    res.send(savedCategory);
} catch (error) {
    res.send(error.message);
}

Of course, it means you will need to create this kind of object first in order to pass it, I used your data as an example. You can sort either in your front-end or back-end, whatever makes more sense to you.

Alternatively, you could create the Category first:

const newCategory = new Category({ categoryName: req.body.categoryName })

then add remaining elements (with arrays you could use loop to push elements dynamically):

const newCategory.subcategories = [{
    "subcategoryName": "chemical enginnering",
    "books": [
        {
            "bookName": "",
            "author": "",
            "ratings": [3, 4, 5, 3],
            "feedbacks": ["awesome book", "very amazing book"],
            "price": 222
        }
    ]
},
{
    "subcategoryName": "mechanical engineering",
    "books": [
        {
            "bookName": "",
            "author": "",
            "ratings": [3, 4, 5, 3],
            "feedbacks": ["awesome book", "very amazing book"],
            "price": 222
        }
    ]
}]

etc.

It really all depends on how your data is structured and how you pass it from your frontend but I think you got the idea.

Note that you got spelling in your sample data, please change 'feedbcks' to 'feedbacks'.

answered Aug 8, 2020 at 2:04

Jakub A Suplicki

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3 Comments

OmarYehiaDev Over a year ago

I got the idea but how to send it in a POST request using Postman?

Jakub A Suplicki Over a year ago

You can post data in body -> raw -> application/json, for example. Feel free to read more about how to use Postman: medium.com/@thejasonfile/…

OmarYehiaDev Over a year ago

Thank you for help

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