mongoose model, array of strings, array of objects structure

Question

I am trying to design my database model and i dont have clue how to fit array of strings and array of objects into it. My current model is:

const mongoose = require("mongoose");
const Schema = mongoose.Schema;

const schema = new Schema({
    email: { type: String, unique: true, required: true },
    hash: { type: String, required: true },
    createdDate: { type: Date, default: Date.now },
    settings: {
        favorites: { /* ??? */ },
        cart: { /* ??? */ },
        states: {
            favorites: { type: Boolean, default: true },
            search: { type: Boolean, default: false },
            category: { type: Schema.Types.Mixed, default: false }
        }
    }
});

schema.set("toJSON", { virtuals: true });

module.exports = mongoose.model("User", schema);

favorites data structure is ['234', '564', '213', '782']

cart example data structure is:

[
    { quantity: 5, marketId: '234' },
    { quantity: 2, marketId: '564' },
    { quantity: 7, marketId: '213' },
    { quantity: 3, marketId: '782' }
]

How can i add this as configuration to the mongoose model?

Answer 1

This can help people facing the issue withArray of Objects in Mongoose Schema:

• To ensure error-proof handling of arrays of objects in Mongoose schemas, define each field with its appropriate type and default value.
• Here we took a blog post with an array of comments. Define the comments array with a default empty array and specify the type for each field within the comments array.

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const blogPostSchema = new Schema({
  title: { type: String, required: true },
  content: { type: String, required: true },
  comments: {
    type: [{
      user: { type: Schema.Types.ObjectId, ref: 'User' },
      text: { type: String, required: true },
      createdAt: { type: Date, default: Date.now }
    }],
    default: []
  }
});

const BlogPost = mongoose.model('BlogPost', blogPostSchema);

module.exports = BlogPost;

This setup ensures that even if the comments array is not provided during document creation, it defaults to an empty array, and each comment object follows the defined structure.

Answer 2

Favorites must be an array of String like this: favorites: [String]

For the cart array we have two main options:

1. We can define the cart as an array of subdocuments.

const schema = new Schema({
  email: { type: String, unique: true, required: true },
  hash: { type: String, required: true },
  createdDate: { type: Date, default: Date.now },
  settings: {
    favorites: [String],
    cart: [
      {
        quantity: Number,
        marketId: String
      }
    ],
    states: {
      favorites: { type: Boolean, default: true },
      search: { type: Boolean, default: false },
      category: { type: Schema.Types.Mixed, default: false }
    }
  }
});

2. Or we can declare cart as an array of schema types.

const schema = new Schema({
  email: { type: String, unique: true, required: true },
  hash: { type: String, required: true },
  createdDate: { type: Date, default: Date.now },
  settings: {
    favorites: [String],
    cart: [
      new Schema({
        quantity: Number,
        marketId: String
      })
    ],
    states: {
      favorites: { type: Boolean, default: true },
      search: { type: Boolean, default: false },
      category: { type: Schema.Types.Mixed, default: false }
    }
  }
});

For both of them, when you create a document, it will look like this, note that mongoose added _id field in the card items.

{
    "settings": {
        "states": {
            "favorites": true,
            "search": false,
            "category": false
        },
        "favorites": [
            "234",
            "564",
            "213",
            "782"
        ],
        "cart": [
            {
                "_id": "5e6cd0bd53feb32d50699b79",
                "quantity": 5,
                "marketId": "234"
            },
            {
                "_id": "5e6cd0bd53feb32d50699b78",
                "quantity": 2,
                "marketId": "564"
            },
            {
                "_id": "5e6cd0bd53feb32d50699b77",
                "quantity": 7,
                "marketId": "213"
            },
            {
                "_id": "5e6cd0bd53feb32d50699b76",
                "quantity": 3,
                "marketId": "782"
            }
        ]
    },
    "_id": "5e6cd0bd53feb32d50699b75",
    "email": "abc@def.net",
    "hash": "hash...",
    "createdDate": "2020-03-14T12:40:29.969Z",
    "__v": 0,
    "id": "5e6cd0bd53feb32d50699b75"
}

If you don't want _id fields in cart array, you can add _id: false option the cart schema like this:

    cart: [
      new Schema(
        {
          quantity: Number,
          marketId: String
        },
        { _id: false }
      )
    ],

Here are some useful docs:

Arrays

Subdocuments