In the world of web development, user authentication plays a crucial role in securing applications and providing a personalized experience to users. One effective approach to implement authentication in Angular applications is by using Ngrx in combination with Firebase Google OAuth. In this article, we will dive deep into how to build a Redux-style authentication system that allows you to leverage the power of state management with Ngrx and the convenience of Firebase for user authentication.

Understanding Ngrx and Firebase

What is Ngrx?

Ngrx is a state management library for Angular that enables developers to build applications with a predictable state. It is inspired by the Redux pattern, making it a popular choice for managing complex state in Angular applications. Ngrx helps in organizing application state, handling side effects, and maintaining the unidirectional flow of data.

What is Firebase Google OAuth?

Firebase Authentication is a service that can authenticate users using only client-side code. It supports various authentication methods, including email and password, phone authentication, and Google sign-in. Google OAuth lets users sign in to your application using their Google credentials, which simplifies the authentication process.

Why Combine Ngrx with Firebase?

Using Ngrx with Firebase allows developers to manage authentication state centrally, providing a clean architecture for the state of your application. This approach ensures that any changes to the authentication state are reflected throughout the app, creating a seamless user experience.

Step-by-Step Guide to Implement Authentication

Step 1: Setting Up Angular with Ngrx and Firebase

To begin, you need to set up your Angular application with Ngrx and Firebase. If you haven’t done so, follow these steps:

1. Create a New Angular Project:

   ng new my-angular-auth-app

2. Install Ngrx and Firebase:

   ng add @ngrx/store @ngrx/effects firebase @angular/fire

3. Configure Firebase:

• Go to the Firebase Console and create a new project.
• In the project settings, add a web app and copy the Firebase configuration object.

Step 2: Authenticating Users with Firebase

Next, you will integrate Firebase to handle Google authentication. Create an authentication service that utilizes Firebase:

import { Injectable } from '@angular/core';
import firebase from 'firebase/app';
import 'firebase/auth';

@Injectable({ providedIn: 'root' })
export class AuthService {
  constructor() {
    // Initialize Firebase
    if (!firebase.apps.length) {
      firebase.initializeApp(firebaseConfig);
    }
  }

  loginWithGoogle() {
    const provider = new firebase.auth.GoogleAuthProvider();
    return firebase.auth().signInWithPopup(provider);
  }

  logout() {
    return firebase.auth().signOut();
  }
}

Step 3: Creating Authentication State with Ngrx

Next, you will create Ngrx actions, reducers, and effects to handle authentication state. 1. Define Actions:

import { createAction, props } from '@ngrx/store';

export const login = createAction('[Auth] Login', props<{ user: any }>());
export const logout = createAction('[Auth] Logout');

2. Create a Reducer:

import { createReducer, on } from '@ngrx/store';
import { login, logout } from './auth.actions';

export interface AuthState {
  user: any;
}

export const initialState: AuthState = {
  user: null,
};

export const authReducer = createReducer(
  initialState,
  on(login, (state, { user }) => ({ ...state, user })),
  on(logout, (state) => ({ ...state, user: null })),
);

3. Create Effects for Side Effects:

import { Injectable } from '@angular/core';
import { Actions, ofType, createEffect } from '@ngrx/effects';
import { AuthService } from './auth.service';
import { login, logout } from './auth.actions';
import { map, switchMap } from 'rxjs/operators';

@Injectable()
export class AuthEffects {
  constructor(private actions$: Actions, private authService: AuthService) { }

  login$ = createEffect(() => this.actions$.pipe(
    ofType(login),
    switchMap(() => this.authService.loginWithGoogle().then(user => map((user) => login({ user }))));
  ));

  logout$ = createEffect(() => this.actions$.pipe(
    ofType(logout),
    switchMap(() => this.authService.logout()),
  ));
}

Step 4: Connecting Everything in Your Application

1. Set up Store and Effects Modules in your app module:

import { StoreModule } from '@ngrx/store';
import { EffectsModule } from '@ngrx/effects';
import { authReducer } from './auth.reducer';
import { AuthEffects } from './auth.effects';

@NgModule({
  imports: [
    StoreModule.forRoot({ auth: authReducer }),
    EffectsModule.forRoot([AuthEffects]),
  ],
})
export class AppModule { }

2. Create Components for User Login and Session Management: Utilize the AuthService in your Angular component to manage user login and logout actions.

Step 5: Testing Your Implementation

Make sure to test your application thoroughly to confirm that the authentication flow works seamlessly. Log in with Google, check the state management, and ensure your component reflects the authentication state.

Conclusion

Building a Redux-style authentication system using Ngrx and Firebase Google OAuth not only helps in maintaining the state efficiently but also enhances user experience by simplifying the authentication process. By structuring your Angular application with Ngrx, you gain benefits like better scalability and easier debugging.

With this guide, you should have a solid foundation for creating a robust authentication system in your Angular applications. As you become more familiar with the concepts, you can customize and extend the functionalities to meet your specific requirements.

Ready to take your Angular skills to the next level? Start implementing these strategies and improve your app’s user experience today!