Nest JS: Create a new Provider / Service

Creating a new Service / Provider in the nest JS app. How to create a Service / Provider in nest JS?

Providers in Nest JS also known as services are basically responsible for executing the business logic. In the Nest JS Service we use @Injectable decorator for the purpose of dependency injection.

Creating a new Service in Nest JS – ( Manual way )

For example, here we are creating a service for the auth functionality of our app.

In the src folder create folder named auth

Inside the auth folder we can create the module file : auth.service.ts

auth.service.ts

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

@Injectable({})
export class AuthService {}

Adding the provider to the module

app.module.ts

import { Module } from '@nestjs/common'
import { AuthController } from './auth.controller';
import { AuthService } from './auth.service';
@Module({
    controllers: [AuthController],
    providers: [AuthService]
    
})
export class AuthModule { }

Dependency injection: Connecting Provider to the controller

auth.controller.ts

import { Controller, Post } from "@nestjs/common";
import { AuthService } from "./auth.service";

@Controller('auth')
export class AuthController{
    constructor(private authService: AuthService) {}
    @Post('signup')
    signup() {
        return this.authService.signup()
    }
    @Post('login')
    login() {
        return this.authService.login()
    }
}

auth.service.ts

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

@Injectable({})
export class AuthService {
    signup(){
        return { msg: 'I have signed up!'};
    }

    login(){
        return { msg: 'I have logged in..!'};
    }
}

Result: