Firebase App

/**
 * Provides Firebase App instance using standalone API
 * @param fn - Function that returns initialized Firebase app
 * @returns Environment providers for dependency injection
 */
export function provideFirebaseApp(
  fn: () => FirebaseApp
): EnvironmentProviders;

/**
 * Initialize Firebase app with configuration
 * @param options - Firebase configuration object
 * @param name - Optional app name for multiple apps
 * @returns Initialized Firebase app instance
 */
export function initializeApp(
  options: FirebaseOptions,
  name?: string
): FirebaseApp;

/**
 * Firebase App NgModule for traditional module-based setup
 */
export class FirebaseAppModule {
  /**
   * Configure Firebase App for root module
   * @param options - Firebase configuration object
   * @param name - Optional app name
   * @returns ModuleWithProviders for root module
   */
  static forRoot(
    options: FirebaseOptions,
    name?: string
  ): ModuleWithProviders<FirebaseAppModule>;
}

/**
 * Injectable service providing access to Firebase App instance
 */
export class FirebaseApp extends FirebaseApp {
  readonly name: string;
  readonly options: FirebaseOptions;
}

/**
 * Collection of all Firebase App instances
 */
export class FirebaseApps extends Array<FirebaseApp> {}

/**
 * Observable stream of Firebase App instances
 */
export const firebaseApp$: Observable<FirebaseApp>;

/**
 * Injection token for provided Firebase App instances
 */
export const PROVIDED_FIREBASE_APPS: InjectionToken<FirebaseApp[]>;

/**
 * Get Firebase app instance by name
 * @param name - App name, defaults to '[DEFAULT]'
 * @returns Firebase app instance
 */
export function getApp(name?: string): FirebaseApp;

/**
 * Get all initialized Firebase apps
 * @returns Array of all Firebase app instances
 */
export function getApps(): FirebaseApp[];

/**
 * Delete Firebase app instance
 * @param app - Firebase app to delete
 * @returns Promise that resolves when app is deleted
 */
export function deleteApp(app: FirebaseApp): Promise<void>;

/**
 * Firebase configuration options
 */
interface FirebaseOptions {
  /** Firebase API key */
  apiKey?: string;
  /** Authentication domain */
  authDomain?: string;
  /** Database URL for Realtime Database */
  databaseURL?: string;
  /** Firebase project ID */
  projectId?: string;
  /** Cloud Storage bucket */
  storageBucket?: string;
  /** Cloud Messaging sender ID */
  messagingSenderId?: string;
  /** Firebase app ID */
  appId?: string;
  /** Google Analytics measurement ID */
  measurementId?: string;
}

/**
 * Firebase app instance interface
 */
interface FirebaseApp {
  /** App name */
  readonly name: string;
  /** App configuration options */
  readonly options: FirebaseOptions;
}

/**
 * Module with providers type for NgModule configuration
 */
interface ModuleWithProviders<T> {
  ngModule: Type<T>;
  providers?: Provider[];
}

/**
 * Environment providers type for standalone API
 */
type EnvironmentProviders = Provider[];

import { bootstrapApplication } from '@angular/platform-browser';
import { provideFirebaseApp, initializeApp } from '@angular/fire/app';

const firebaseConfig = {
  apiKey: "your-api-key",
  authDomain: "your-project.firebaseapp.com",
  projectId: "your-project-id",
  storageBucket: "your-project.appspot.com",
  messagingSenderId: "123456789",
  appId: "your-app-id"
};

bootstrapApplication(AppComponent, {
  providers: [
    provideFirebaseApp(() => initializeApp(firebaseConfig)),
    // Other providers...
  ],
});

import { provideFirebaseApp, initializeApp } from '@angular/fire/app';

bootstrapApplication(AppComponent, {
  providers: [
    // Default app
    provideFirebaseApp(() => initializeApp(primaryConfig)),
    // Secondary app
    provideFirebaseApp(() => initializeApp(secondaryConfig, "secondary")),
  ],
});

import { Component, inject } from '@angular/core';
import { FirebaseApp } from '@angular/fire/app';

@Component({
  selector: 'app-example',
  template: `<p>App Name: {{ app.name }}</p>`,
})
export class ExampleComponent {
  app = inject(FirebaseApp);

  ngOnInit() {
    console.log('Firebase app initialized:', this.app.name);
    console.log('Project ID:', this.app.options.projectId);
  }
}

import { NgModule } from '@angular/core';
import { FirebaseAppModule, initializeApp } from '@angular/fire/app';

const firebaseConfig = {
  // Your config
};

@NgModule({
  imports: [
    FirebaseAppModule.forRoot(firebaseConfig),
  ],
  // Other module configuration...
})
export class AppModule {}