Angular Cli Generate a Service and Include the Provider in One Step

Angular 6+ Singleton Services

The recommended approach for a singleton service for Angular 6 and beyond is :

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root',
})
export class UserService {
}

In fact the CLI --module switch doesn't even exist any more for registering a service at the app level because it doesn't need to modify app.module.ts anymore.

This will create the above code, without needing to specify a module.

ng g s services/user

So if you don't want your service to be a singleton you must remove the providedIn code yourself - and then add it manually to providers for a component or lazy loaded module. Doesn't look like there is currently a switch to not generate the providedIn: 'root' part so you need to manually remove it.

Specify paths

--app
  --one
    one.module.ts
    --services

  --two
    two.module.ts
    --services

Create Service with new folder in module ONE

ng g service one/services/myNewServiceFolderName/serviceOne --module one/one

--one
  one.module.ts // service imported and added to providers.
  --services
    --myNewServiceFolderName
      serviceOne.service.ts
      serviceOne.service.spec.ts

slight change in syntax from the accepted answer for Angular 5 and angular-cli 1.7.0

ng g service backendApi --module=app.module

Looks like in Angular v11 and higher, we don't have option "s" anymore:

ng g service services/backendApi

or like that:

ng g service services/backendApi --flat --skipTests=true

Add a service to the Angular 4 app using Angular CLI

An Angular 2 service is simply a javascript function along with it's associated properties and methods, that can be included (via dependency injection) into Angular 2 components.

To add a new Angular 4 service to the app, use the command ng g service serviceName. On creation of the service, the Angular CLI shows an error:

To solve this, we need to provide the service reference to the src\app\app.module.ts inside providers input of @NgModule method.

Initially, the default code in the service is:

import { Injectable } from '@angular/core';

@Injectable()
export class ServiceNameService {

  constructor() { }

}

A service has to have a few public methods.

In Angular 5.12 and latest Angular CLI, do

ng generate service my-service -m app.module

ng generate service userService

//shorthand for creating service
ng g s serviceName

** When you fire this command it will automatically registered inside providers array. **

providers: [
    UserService
]

In Command prompt go to project folder and execute following:

ng g s servicename

run the below code in Terminal

makesure You are inside your project folder in terminal

ng g s servicename --module=app.module