app.module

import { NgModule, LOCALE_ID} from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { LocaleService } from './locale.service';

@NgModule({
  imports:      [BrowserModule],
  declarations: [AppComponent],
  bootstrap:    [AppComponent],
  providers: [
    LocaleService,
    {
      provide: LOCALE_ID,
      deps: [LocaleService],
      useFactory: ($locale: LocaleService) => $locale.get()
    }]
})
export class AppModule { }