How to inject service from another module into nestjs modules

This tutorial explains how to inject Service from one mon=dule to another module in the NestJS application with an example.

In another way, how to share and export a service and import it into another module.

How to Inject Service from one module to another module

For example, I created EmployeeModule and DepartmentModule.

Create Employee Module, Controller, and Service.

First, Create an EmployeeModule using the below command

A:\work\nestjs-hello-world>nest generate module employee
CREATE src/employee/employee.module.ts (85 bytes)
UPDATE src/app.module.ts (326 bytes)

The module is created as follows

import { Module } from "@nestjs/common";
import { EmployeeModule } from "./employee/employee.module";

@Module({
  imports: [EmployeeModule],
  controllers: [],
  providers: [],
})
export class AppModule {}

Next, Create an EmployeeController using the below command

A:\work\nestjs-hello-world>nest generate co Employee
CREATE src/employee/employee.controller.ts (105 bytes)
CREATE src/employee/employee.controller.spec.ts (506 bytes)
UPDATE src/employee/employee.module.ts (182 bytes)

a controller and test spec file created as given below.

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

@Controller("employee")
export class EmployeeController {}

Also, updates the controller section in employee.module.ts

import { Module } from "@nestjs/common";
import { EmployeeController } from "./employee.controller";

@Module({
  controllers: [EmployeeController],
})
export class EmployeeModule {}

Next, Create an EmployeeService using the below command

A:\work\nestjs-hello-world>nest generate service Employee
CREATE src/employee/employee.service.ts (92 bytes)
CREATE src/employee/employee.service.spec.ts (474 bytes)
UPDATE src/employee/employee.module.ts (268 bytes)

service and spec file created

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

@Injectable()
export class EmployeeService {}

Also, updated this service file in the Module file(employee.module.ts)

import { Module } from "@nestjs/common";
import { EmployeeController } from "./employee.controller";
import { EmployeeService } from "./employee.service";

@Module({
  controllers: [EmployeeController],
  providers: [EmployeeService],
})
export class EmployeeModule {}

Let’s add some dummy method, that returns a string in Employee Service.

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

@Injectable()
export class EmployeeService {

    public getEmployee(): String{
        return "Employee object"
    }

}

Create Department Module, Controller, and service

First, create department a module

A:\work\nestjs-hello-world>nest g module department
CREATE src/department/department.module.ts (87 bytes)

Next, create department a controller

A:\work\nestjs-hello-world>nest g controller department
CREATE src/department/department.controller.ts (109 bytes)
CREATE src/department/department.controller.spec.ts (520 bytes)
UPDATE src/department/department.module.ts (190 bytes)

Next, create department a service

A:\work\nestjs-hello-world>nest g service department
CREATE src/department/department.service.ts (94 bytes)
CREATE src/department/department.service.spec.ts (488 bytes)
UPDATE src/department/department.module.ts (282 bytes)

Created Employee and Department modules.

Now, Let’s do EmployeeService from EmployeeModule injected into DepartmentModule.

The first step is -Make EmployeeService exportable in the Employee module added exports: [EmployeeService] to the @module section of EmployeeModule. It means, EmployeeService is declared as exported and can be ready to access in other modules. employee.module.ts:

import { Module } from "@nestjs/common";
import { EmployeeController } from "./employee.controller";
import { EmployeeService } from "./employee.service";

@Module({
  controllers: [EmployeeController],
  providers: [EmployeeService],
  exports: [EmployeeService],
})
export class EmployeeModule {}

Next Step, EmployeeService is declared in EmployeeModule, so import EmployeeModule into DepartmentModule. added imports: [EmployeeModule] to DepartmentModule.

department.module.ts:

import { Module } from "@nestjs/common";
import { EmployeeModule } from "src/employee/employee.module";
import { EmployeeService } from "src/employee/employee.service";
import { DepartmentController } from "./department.controller";
import { DepartmentService } from "./department.service";

@Module({
  imports: [EmployeeModule],
  controllers: [DepartmentController],
  providers: [DepartmentService],
})
export class DepartmentModule {}

Now, you are ready to use EmployeeService in department modules and controller code.

EmployeeService is injected into the constructor. use service class inside controller methods.

import { Controller, Get } from "@nestjs/common";
import { EmployeeService } from "src/employee/employee.service";

@Controller("department")
export class DepartmentController {
  constructor(private employeeService: EmployeeService) {}

  @Get()
  getEmployeeDepartment(): string {
    return this.employeeService.getEmployee();
  }
}

Conclusion

If you want to use Service in another module First export Service Next, Import the service module into another module

How to inject service from another module into nestjs modules

#How to Inject Service from one module to another module

#Conclusion

How to Inject Service from one module to another module

Conclusion