Basic Usage

note

Check out this example project if you need help.

You can check out the example project for more details.

We will be creating a CatsModule, a Cat database model, a CatsService, and a CatsController.

Connecting to the MongoDB database

First, we will connect to the mongo database using TypegooseModule.forRoot. We will import the CatsModule that we will create shortly.

If you want to have more connections to different databases read about how to do that here.

app.module.ts

import { Module } from "@nestjs/common";

import { TypegooseModule } from "nestjs-typegoose";

import { CatsModule } from "./cat.module.ts";

@Module({

imports: [

TypegooseModule.forRoot("mongodb://localhost:27017/nest", {

useNewUrlParser: true

}),

CatsModule

]

})

export class ApplicationModule {}

Here we are connecting to mongodb://localhost:27017/nest. To learn more about MongoDB URI's see the official mongodb article.

Creating a Database Model

We now need to create a database model that describes the data we want to store. In this case, it will be cats with names. Read more about typegoose here.

cat.model.ts

import { prop } from "@typegoose/typegoose";

export class Cat {

@prop({ required: true })

name: string;

}

Creating the service

We need to create a service to handle the business logic of creating, reading, updating, and deleting (CRUD) entires, or cats, in the database.

cats.service.ts

import { Injectable } from "@nestjs/common";

import { InjectModel } from "nestjs-typegoose";

import { Cat } from "./cat.model";

import { ReturnModelType } from "@typegoose/typegoose";

@Injectable()

export class CatsService {

constructor(

@InjectModel(Cat) private readonly catModel: ReturnModelType<typeof Cat>

) {}

async create(createCatDto: { name: string }): Promise<Cat> {

const createdCat = new this.catModel(createCatDto);

return await createdCat.save();

}

async findAll(): Promise<Cat[] | null> {

return await this.catModel.find().exec();

}

}

Connecting with the API

Now we have the service created we need to connect this with the actual API calls. The CatsController will receive GET and POST requests on the URL /cats and will get and create cats respectively.

cats.controller.ts

import { Controller, Get, Post, Body } from "@nestjs/common";

import { CatsService } from "./cats.service";

import { Cat } from "./cats.model.ts";

@Controller("cats")

export class CatsController {

constructor(private readonly catsService: CatsService) {}

@Get()

async getCats(): Promise<Cat[] | null> {

return await this.catsService.findAll();

}

@Post()

async create(@Body() cat: Cat): Promise<Cat> {

return await this.catsService.create(cat);

}

}

Providing the model for our services

We have to make sure we provide the needed models to our service with TypegooseModule.forFeature for the InjectModel to work. This helps prevents unauthorized access to other models.

cat.module.ts

import { Module } from "@nestjs/common";

import { TypegooseModule } from "nestjs-typegoose";

import { Cat } from "./cat.model";

import { CatsController } from "./cats.controller";

import { CatsService } from "./cats.service";

@Module({

imports: [TypegooseModule.forFeature([Cat])],

controllers: [CatsController],

providers: [CatsService]

})

export class CatsModule {}

That's it, you have created a simple working api with nestjs-typegoose!