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

@Injectable()

export class LoggerServiceService {

  constructor() { }

  log(message: string) {

    console.log(message);

  }

}

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

import { LoggerServiceService } from './logger-service.service';

@Injectable()

export class ProductServiceService {

  constructor(private logger: LoggerServiceService) { }

  getProduct(): Product {

    this.logger.log("iPhone7");

    return new Product(, "iPhone7");

  }

}

export class Product {

  constructor(

    public id: number,

    public title: string

  ) { }

}

import { BrowserModule } from '@angular/platform-browser';

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

import { AppComponent } from './app.component';

import { Product1Component } from './product1/product1.component';

import { ProductServiceService } from './shared/product-service.service';

import { Product2Component } from './product2/product2.component';

import { LoggerServiceService } from './shared/logger-service.service';

@NgModule({

  declarations: [

    AppComponent,

    Product1Component,

    Product2Component

  ],

  imports: [

    BrowserModule

  ],

  providers: [ProductServiceService,LoggerServiceService],

  bootstrap: [AppComponent]

})

export class AppModule { }