what does module exports = mongoose model do in NodeJs

Question

I am coming sort of front-end React world and have mostly used statements like import and exports.

I know there are numerous article highlighting How we can use import and export in nodeJS and I also know that this might not have anything to do with import and export.

Either way, I was starting to learn Backend (NodeJs) along with mongoDB.

I am using express framework and package name mongoose.

Inside, models, we were creating a schema as simple as this

const mongoose = require('mongoose')

const bookSchema = new mongoose.Schema({
    name: String,
    genre: String, 
    authorID: String
})


module.exports = mongoose.model("Books", bookSchema)

While I understand what we are doing above, creating a schema above and exporting, I am unable to comprehend the export statement

module.exports = mongoose.model("Books", bookSchema)

Like, I understand it does export mongoose schema but what does mongoose.model do/mean? like behind the scenes?

Answer 1

According to the documentation

Models are fancy constructors compiled from Schema definitions. An instance of a model is called a document. Models are responsible for creating and reading documents from the underlying MongoDB database.

---

Schema are the description of the data. Model kind of represent your collection. You can have multiple Model having the same Schema. To create new documents, or to get documents from database, you need to use Model.

---

To use the model as you described it :

a.js

// ...

module.exports = mongoose.model('Books', bookSchema)

b.js

import Books from 'a.js';

// We create a new document and then save it in database    
const book = new Books({
  name: 'Harry potter',
  genre: 'drama',
  authorID: 'JK',
});

// Save is asynchronous and can fail
await book.save();