Philosophy

Models are objects that aim to manage a single document in a collection, it also provides multiple ways of creating, updating, deleting and fetching documents as utilities.

What is a model?

A model basically is a class that represents a document in a collection, this helps us to manage the document in a more object oriented way.

Why not dealing with documents directly?

Because when your application grows, you'd need to do more complex operations over documents, let's take an example, when we save a new model it automatically creates a new unique id for that document, and we can access that id using the id property, you would need to do this manually each time you create a new document, and this is just a simple example, there are many other things that you'd need to do manually if you don't use models.

Creating a model

To create a model, you need to extend the Model class and define the collection property.

src/models/user.ts

import { Model } from "@mongez/monpulse";

export class User extends Model {
    /**
    * The collection name
    */
    public static collection = "users";
}

This is the bare minimum to create a model, but we can do more, we'll see that as long as we go.

How to use a model?

When creating a new model instance, you optionally pass an object of the data that will be saved (created).

src/app.ts

import { User } from "./models/user";

const user = new User({
    name: "Hasan Zohdy",
    email: "hassanzohdy@gmail.com",
    isActive: true,
});

This only creates an instance of the model, but the data is not saved yet, now let's see how to save the data.

Saving a model instance

To save a model instance, you need to call the save method.

src/app.ts

import { User } from "./models/user";

async function main() {
    const user = new User({
        name: "Hasan Zohdy",
        email: "hassanzohdy@gmail.com",
        isActive: true,
    });

    await user.save();
}

Once the model is successfully saved, a new id is assigned to the model instance.

Accessing Document ids

By default, MongoDB generates _id for each document, and it's a unique identifier for each document in the collection, we can access the document id using the _id property.

src/app.ts

import { User } from "./models/user";

async function main() {
    const user = new User({
        name: "Hasan Zohdy",
        email: "hassanzohdy@gmail.com",
        isActive: true,
    });

    await user.save();

    const _id = user._id;

    console.log(_id); // ObjectId("5f9b2b3b3f3b9a0b3c3b9a0b")
}

This is good, but honestly i prefer ids as numbers, so we can use the good benefit of the auto generated id.

src/models/user.ts

import { User } from "./models/user";

async function main() {
    const user = new User({
        name: "Hasan Zohdy",
        email: "hassanzohdy@gmail.com",
        isActive: true,
    });

    await user.save();

    const id = user.id;

    console.log(id); // 1424151
}

Any generated id is randomly generated by default, later we'll see how to generate ids in a sequential way on all models or on a specific model.