How to use the angularfire2.AngularFireModule.initializeApp function in angularfire2

apiKey: 'YOUR_API_KEY',
  authDomain: 'YOUR_DOMAIN',
  databaseURL: 'YOUR_DATABASE_URL',
  storageBucket: 'YOUR_STORAGE',
  messagingSenderId: "YOUR_MSGINGID"
};

@NgModule({
  declarations: [
    MyApp,
    HomePage
  ],
  imports: [
    BrowserModule,
    HttpModule,
    AngularFireModule.initializeApp(firebaseConfig),
    AngularFireDatabaseModule, // imports firebase/database, only needed for database features
    AngularFireAuthModule, // imports firebase/auth, only needed for auth features
    IonicModule.forRoot(MyApp)
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage
  ],
  providers: [
    PictureUtils,
    Camera,
    { provide: ErrorHandler, useClass: IonicErrorHandler }
  ]
})
export class AppModule { }

FooterComponent,
    PinsComponent,
    PinItemComponent,
    PinDetailComponent,
    ModalComponent,
    PinEditComponent,
    PinCommentComponent,
    PinCommentNewComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    ReactiveFormsModule,
    HttpModule,
    AppRoutes,
    AngularFireModule.initializeApp(firebaseConfig, {
      provider: AuthProviders.Google,
      method: AuthMethods.Popup
    }),
    RouterModule.forRoot(routes),
    StoreModule.provideStore(reducer, {
      router: {
        path: window.location.pathname + window.location.search
      }
    }),
    // StoreDevtoolsModule.instrumentOnlyWithExtension(),
    RouterStoreModule.connectRouter(),
    EffectsModule.run(UserAuthEffects),
    EffectsModule.run(PinEffects),
    EffectsModule.run(CommentEffects),
    EffectsModule.run(NotificationEffects),
    MasonryModule,

import { LoginComponent } from './storefront-components/login/login.component';

// services
import { GlobalService } from './services/global.service';
import { WindowRefService } from "./services/window-ref.service";
import { LocalCartService } from "./services/localcart.service";

// directives
import { StopPropagationDirective } from './directives/stop-propagation.directive';

firebase.initializeApp(environment.firebase);

@NgModule({
  imports: [
    BrowserModule,
    AngularFireModule.initializeApp(environment.firebase, 'firebase-cms'),
    AngularFireDatabaseModule,
    AngularFireAuthModule,
    BrowserAnimationsModule,
    FormsModule,
    AppRoutingModule,
    MaterialComponentsModule,
    SharedModule,
  ],
  declarations: [
    AppComponent,
    CartComponent,
    CartIconComponent,
    CheckoutShippingComponent,
    CheckoutBillingComponent,
    CheckoutPaymentComponent,
    CheckoutReviewComponent,

import { NgModule } from '@angular/core';
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule } from 'angularfire2/database';
import { AngularFireAuthModule } from 'angularfire2/auth';

const config = {
  apiKey: process.env.FIREBASE_APIKEY,
  authDomain: process.env.FIREBASE_AUTHDOMAIN,
  databaseURL: process.env.FIREBASE_DATABASEURL,
  storageBucket: process.env.FIREBASE_STORAGE
};

@NgModule({
  imports: [
    AngularFireModule.initializeApp(config),
    AngularFireDatabaseModule,
    AngularFireAuthModule
  ]
})
export default class AppFirebaseModule {}

import { afConfig, afAuthConfig } from './firebase.credential';

import { SharedModule } from '../shared/shared.module';

import { SocialAuthComponent } from './social-auth/social-auth.component';
import { AuthService } from './auth.service';

import { NavbarComponent } from './navbar.component';

import { NavbarRoutingModule, routedComponents } from './routing.module';

@NgModule({
  imports: [
    SharedModule,
    NavbarRoutingModule,
    AngularFireModule.initializeApp(afConfig, afAuthConfig)
  ],
  declarations: [
    routedComponents
  ],
  exports: [
    SocialAuthComponent,
    NavbarComponent
  ],
  providers: [ 
    AuthService
  ]
})
export class NavbarModule { }

beforeEach(() => {
    TestBed.configureTestingModule({
      imports: [
        AngularFireModule.initializeApp(COMMON_CONFIG, FIREBASE_APP_NAME),
        AngularFireDatabaseModule
      ]
    });
    inject([FirebaseApp, AngularFireDatabase], (app_: FirebaseApp, _db: AngularFireDatabase) => {
      app = app_;
      db = _db;
      app.database().goOnline();
      createRef = (path: string) => { app.database().goOnline(); return app.database().ref(path); };
    })();
  });

authDomain: 'https://angularfire2-offline.firebaseio.com',
  databaseURL: 'https://angularfire2-offline.firebaseio.com',
  storageBucket: 'gs://angularfire2-offline.appspot.com'
};

@NgModule({
  declarations: [
    MyApp,
    AboutPage,
    ContactPage,
    HomePage,
    TabsPage
  ],
  imports: [
    AngularFireDatabaseModule,
    AngularFireModule.initializeApp(firebaseConfig),
    AngularFireOfflineModule,
    BrowserModule,
    IonicModule.forRoot(MyApp)
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    AboutPage,
    ContactPage,
    HomePage,
    TabsPage
  ],
  providers: [
    StatusBar,
    SplashScreen,
    {provide: ErrorHandler, useClass: IonicErrorHandler}

import { MyApp } from './app.component';
import { HomePage } from '../pages/home/home';

import { environment } from '../environment';
import { GoogleCloudVisionServiceProvider } from '../providers/google-cloud-vision-service/google-cloud-vision-service';

@NgModule({
  declarations: [
    MyApp,
    HomePage
  ],
  imports: [
    BrowserModule,
    HttpModule,
    IonicModule.forRoot(MyApp),
    AngularFireModule.initializeApp(environment.firebaseConfig),
    AngularFireDatabaseModule,
    AngularFireAuthModule
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    HomePage
  ],
  providers: [
    StatusBar,
    SplashScreen,
    Camera,
    {provide: ErrorHandler, useClass: IonicErrorHandler},
    GoogleCloudVisionServiceProvider
  ]
})

MyApp,
    IntroSlidesPage,
    LoginPage,
    RegisterPage,
    ForgotPassPage,
    ProductsPage,
    ProductDetailsPage,
    CartPage,
    OrdersPage,
    BillingPage,
    LogoutPage
  ],
  imports: [
    BrowserModule,
    IonicModule.forRoot(MyApp),
    AngularFireModule.initializeApp({         //<----ENTER FIREBASE CREDENTIAL HERE
      apiKey: "",
      authDomain: "",
      databaseURL: "",
      projectId: "",
      storageBucket: "",
      messagingSenderId: ""
    }),                                       
    AngularFireDatabaseModule,                
    AngularFireAuthModule                     
  ],
  bootstrap: [IonicApp],
  entryComponents: [
    MyApp,
    IntroSlidesPage,
    LoginPage,
    RegisterPage,